ChemicalThermodynamics
Unit 14Chemical
ThermodynamicsDr Jorge L AlonsoMiami-Dade College ndash Kendall Campus
Miami FL
Textbook Reference bullChapter 15 (sec12-17)bullModule 3 (sec VIII-XII)
CHM 1046 General Chemistry and Qualitative Analysis
ChemicalThermodynamics
First Law of Thermodynamics
bull The law of conservation of energy energy cannot be created nor destroyed (James Joule in 1843 )
E = q + ww = PV
E = q + PVE = q + RT
Esys + Esurr = 0
Esys = -Esurr
bull Therefore the total energy of the universe is a constant
bull Energy can however be converted from one form to another or transferred from a system to the surroundings or vice versa
ChemicalThermodynamics
Second Law of Thermodynamics
Do all processes that loose energy occur
spontaneously (by themselves without
external influence)
First Law of ThermodynamicsStoneE1
E2
E = E2 ndash E1
Spontaneity
+ Work
- (work + heat)
ChemicalThermodynamics
Spontaneous Processesbull can proceed without any outside intervention
Spontaneity
Processes that are spontaneous in one direction
are nonspontaneous
in the reverse direction
ChemicalThermodynamics
Spontaneous Processesbull Processes that are spontaneous at one temperature
may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous
Is the spontaneity of
melting ice dependent on
anything
Spontaneous T gt 0ordmC
Spontaneous T lt 0ordmC
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
First Law of Thermodynamics
bull The law of conservation of energy energy cannot be created nor destroyed (James Joule in 1843 )
E = q + ww = PV
E = q + PVE = q + RT
Esys + Esurr = 0
Esys = -Esurr
bull Therefore the total energy of the universe is a constant
bull Energy can however be converted from one form to another or transferred from a system to the surroundings or vice versa
ChemicalThermodynamics
Second Law of Thermodynamics
Do all processes that loose energy occur
spontaneously (by themselves without
external influence)
First Law of ThermodynamicsStoneE1
E2
E = E2 ndash E1
Spontaneity
+ Work
- (work + heat)
ChemicalThermodynamics
Spontaneous Processesbull can proceed without any outside intervention
Spontaneity
Processes that are spontaneous in one direction
are nonspontaneous
in the reverse direction
ChemicalThermodynamics
Spontaneous Processesbull Processes that are spontaneous at one temperature
may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous
Is the spontaneity of
melting ice dependent on
anything
Spontaneous T gt 0ordmC
Spontaneous T lt 0ordmC
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Second Law of Thermodynamics
Do all processes that loose energy occur
spontaneously (by themselves without
external influence)
First Law of ThermodynamicsStoneE1
E2
E = E2 ndash E1
Spontaneity
+ Work
- (work + heat)
ChemicalThermodynamics
Spontaneous Processesbull can proceed without any outside intervention
Spontaneity
Processes that are spontaneous in one direction
are nonspontaneous
in the reverse direction
ChemicalThermodynamics
Spontaneous Processesbull Processes that are spontaneous at one temperature
may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous
Is the spontaneity of
melting ice dependent on
anything
Spontaneous T gt 0ordmC
Spontaneous T lt 0ordmC
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Spontaneous Processesbull can proceed without any outside intervention
Spontaneity
Processes that are spontaneous in one direction
are nonspontaneous
in the reverse direction
ChemicalThermodynamics
Spontaneous Processesbull Processes that are spontaneous at one temperature
may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous
Is the spontaneity of
melting ice dependent on
anything
Spontaneous T gt 0ordmC
Spontaneous T lt 0ordmC
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Spontaneous Processesbull Processes that are spontaneous at one temperature
may be nonspontaneous at other temperaturesbull Above 0C it is spontaneous for ice to meltbull Below 0C the reverse process is spontaneous
Is the spontaneity of
melting ice dependent on
anything
Spontaneous T gt 0ordmC
Spontaneous T lt 0ordmC
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Spontaneity
Thermodynamics vs Kinetics
C diamond C graphite
vs Speed
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Stone
+ Work
Irreversible Processes
bull Heat energy is lost to dissipation and that energy will not be recoverable if the process is reversed
bull Irreversible processes cannot be undone by exactly reversing the change to the system
bull Spontaneous processes are irreversible
In a reversible process the system changes in such a way that the system and surroundings can be put back in their original states by exactly reversing the process
E1
E2
- (work + heat)
Reversible Processes
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy (S)
bull Entropy (S) is a term coined by Rudolph Clausius in the 1850rsquos Clausius chose S in honor of Sadi Carnot (who gave the first successful theoretical account of heat engines now known as the Carnot cycle thereby laying the foundations of the second law of thermodynamics)
bull Clausius was convinced of the significance of the ratio of heat delivered and the temperature at which it is delivered
qTEntropy (S) =
Entropy is a measure of the energy that becomes dissipated and unavailable (friction molecular motion = heat)
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy (S)bull Entropy can be thought of
as a measure of the randomness (disorder) of a system
bull It is related to the various modes of motion in molecules
EntropyWaterBoiling
bull Like total energy E and enthalpy H entropy is a state function
bull Therefore S = Sfinal Sinitial Solid
Liquid
GasENTROPY
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Second Law of Thermodynamics
bull the entropy of the universe increases for spontaneous (irreversible) processes
bull the entropy of the universe does not change for reversible processes
Suniv = Ssystem + Ssurroundings gt 0
Suniv = Ssystem + Ssurroundings = 0
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Second Law of Thermodynamics
All spontaneous processes cause the entropy of the universe to increase
ENTROPIC DOOMENTROPIC DOOM
So what is our fate as a result of the second law operating in our Universe
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy on the Molecular Scalebull Molecules exhibit several types of motion (Kinetic energies)
Translational Movement of a molecule from one place to another Vibrational Periodic motion of atoms within a molecule Rotational Rotation of the molecule on about an axis or rotation about
bonds
bull Boltzmann envisioned the motions of a sample of molecules at a particular instant in time This would be akin to taking a snapshot of all the
molecules He referred to this sampling as a microstate (W) of the
thermodynamic systembull Entropy is helliphellip
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy on the Molecular Scale
bull The number of microstates (W) and therefore the entropy (S) tends to increase with increases in which variableshellip
Temperature (T)
Volume (V)
The number of independently moving molecules ()
S = k ln Whellipwhere k is the Boltzmann constant 138 1023 JK
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy Changes
CaCl2 (s) Ca 2+(aq) + 2Cl-(aq)
H2O
H2O (l) H2O(g)Heat
2 H2O (l) 2 H2 (g) + O2(g)Electricity
16 CO2(g) + 18 H2O(g)2 C8H18 (l) + 25 O2 (g)
gas= 34-25 = +92 = 45 C8H18
bull In which of the following does Entropy increase amp WHYhelliphellipGases are formed from liquids and solids
Liquids or solutions are formed from solids
The number of gas molecules (or moles) increasesEntropySolutionsKMnO4(aq)
EntropyampPhaseOfMatter
bull Entropy increases with the freedom of motion of molecules
S(g) gt S(l) gt S(s)
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Third Law of Thermodynamics
The entropy (S) of a pure crystalline substance at absolute zero (-273degC) is 0
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Standard Entropiesbull Standard entropies tend to increase with increasing
molar mass
bull Larger and more complex molecules have greater entropies (greater ways to execute molecular motions)
EntropyampMolecuarSize EntropyampTempC7H15 500 K S=921JnK vs 200 K
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Absolute Entropy (S)
- 237degC (0 K) S = 0
Standard Entropy (S˚)
25degC (298 K) S =
dT298
0 TC
T
TCS
K 298T
0T
TTC
TTmc
T
q S
Calculate the sum of all the infinitesimally small changes in entropy as T varies from T=0 T= 298 by taking its Integral
Standard Entropies (298 K) from Absolute Entropies (0K)
Sdeg
Temp (K)
Solid Liquid Gas
Hdegfus
Hdegvap
q = mcT
q = mcT
q = mcT
298
S
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy Changes in the System
where n and m are the coefficients in the balanced chemical equation
oreactants
oproducts
o298 SmSnS
Sdegsyst = Sdegrxn T
Entropy changes for a reaction (= system) can be estimated in a manner analogous to that by which H is estimated
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Problem Calculate the standard entropy changes for the following reaction at 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g)
Sdeg = nSdeg(prod) - mSdeg(react)
Sdeg = - 1983 J
2(1925) ndash [(1915)+3(1306)]
Entropy Changes in the System
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
oreactants
oproducts
o298 S S S
Thermodynamic Changes in Systems (Chem Reactions)
Appendix 1 (CHM 1046 Module) notice Sdeg is in J not kJ
Grxn = Gf (products) Gf (reactants)
Hrxn = Hf (products) - Hf (reactants)
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy Changes in the Surroundings
bull Heat (q) that flows into or out of the system changes the entropy of the surroundings
Ssurr prop - (qsys)bull For an isothermal process
Ssurr= (qsys)T
bull At constant pressure qsys is simply H for the system
System
q
q
q
q
q
Ssurr= Hsys
TSurroundings
What in a chemical reaction causes entropy changes in the surroundings
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy Change in the Universe
K 298
1000 692( kJ) Jxmol kJ
Problem Calculate the Suniv for the synthesis of ammonia 25oC
N2 (g) + 3 H2 (g) 2 NH3 (g) Hdegrxn = - 926 kJmol
Ssurr =-Hsys
T
Ssurr = 311 JKmol
Suniv = Ssyst or rxn + Ssurr
nS(prod) - mS(react)
Sdegsyst = - 199 JKmiddotmol
2(1925) ndash [(1915)+3(1306)]
Suniv = - 1983 JKmiddotmol + 311 JKmol
Suniv = 113 JKmol
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Entropy Change in the Universe
bull ThenSuniv = Ssyst + Hsystem
T
Suniv = Ssyst or rxn + Ssurr
Ssurr =-Hsys
Tbull Since
TSuniv = Hsyst TSsyst
TSuniv is defined as the Gibbs (free) Energy G
TSuniv = TSsyst + Hsyst
J Willard Gibbs USA 1839-1903
Multiplying both sides by T
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
bull When Suniv is positive G is negative
bull When G is negative the process is spontaneous
Gibbs Free Energy (G)
Gibbs Energy (-TΔS) measures the useful or process-initiating work obtainable from an isothermal isobaric thermodynamic system Technically the Gibbs free energy is the maximum amount of non-expansion work which can be extracted from a closed system or this maximum can be attained only in a completely reversible process
Guniv = Hsys TSsysTSuniv =
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Free Energy Changes
At temperatures other than 25degC
Gdeg = H TS
How does G change with temperature
bull There are two parts to the free energy equation Hmdash the enthalpy term TS mdash the entropy term
bull The temperature dependence of free energy then comes from the entropy term
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Gdeg = H TS
Spontaneous all T
NonSpontaneous all T
Spontaneous high TSpontaneous low T
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Spontaneity Enthalpy amp Entropy
Entropy Driven Reactions
Entropy amp Enthalpy Driven Reaction
Enthalpy Driven Reaction
Na2CO3(s) + HCl(aq) NaCl(aq) + CO2 (g)
2 H2(g) + O2 (g) 2 H2O(g)
NH4NO3(s) NH4+
(aq) + NO3-(aq)
n = 2-3 = -1
S = +H = +
G = H( TS)
EntropySyst+SurrFormationOfWater
(-TS)
(-TS)
(+TS)H = - S = -
H = - S = +
Enthalpy EntropyH2O
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ProblemsGdeg = HT(S)
(-763)
ndash (-804)
+41
(3549)
ndash (2219)
+1330
Gdeg = H TS = (1313kJ) T(133kJ)
T = 987
TiCl4(l) TiCl4(g)
(-T)Reactant
Product
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Standard Free Energy Changes
Analogous to standard enthalpies of formation are standard free energies of formation G
f
G = nG(products) mGf (reactants)f
where n and m are the stoichiometric coefficients
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Standard Free Energy Changes
12 CO2(g) + 6 H2O(g)2 C6H6 (l) + 15 O2 (g)
Grxn = nG(prod) mG(react)f
Calculate the standard free energy changes for the above reaction 25 degC
f
[12(-394) + 6(-229)] ndash [2(125) + 15 (0)]
ndash [2 C6H6 (l) + 15 O2(g)][12 CO2(g) + 6 H2O(g)]
Grxn = - 6352 Jmol K
Standard Molar Gibbs Energy of Formation (Gdegf)
CO2 (g) -394
H2O (g) -229
C6H6 (l) 125
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
Fourth Law of Thermodynamics EmergenceComplex emergent systems spontaneously (-G) arise when energy flows through a collection of many interacting particles resulting in new patterns of complex behaviors that are much more than the sum of the individual parts (+S)
The formation of these complex patterns in emergent systems is more efficient in the dissipation of energy (-H) thus speeds up the increase of entropy in the universe
G = H -TSA precise definition of emergence and a useful mathematical formulation of this phenomenon remains elusive
C f [n i E(t)]Examples cells forming living organisms stars forming galaxies neurons forming conscious brain
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2002 B
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2003 A
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 A
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2004 B
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2005 A
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2006 (B)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
2007 (A)
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics
ChemicalThermodynamics