IB Chemistry on Stoichiometry, Ionic Equation and Balancing Chemical Equation
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Chemical formula • Represent chemical compound • Show elements present in compound
Name compound
Chemical Formula
Name of each element
Sulphuric acid H2SO4 2 Hydrogen, 1 Sulphur, 4 Oxygen
Ammonia NH3 1 Nitrogen, 3 Hydrogen
Hydrogen Chloride HCI 1 Hydrogen, 1 Chlorine
Nitric Acid HNO3 1 Hydrogen, 1 Nitrogen, 3 Oxygen
Empirical formula • Represent simplest whole number ratio of atoms of the elements • Formula obtain by experiment
Molecular formula • Represent actual number atoms of elements that combine to form compound
Structural formula • Represent arrangement of atoms in a compound
Chemical Compound Ethene
C1H1
C2H2
Video tutorial on Molecular/empirical formula
Khan Academy
Chemical Reaction
Word equation
CaCO3 (s) + 2HCI(aq) → CaCI2(aq) + CO2(g) + H2O(l)
Physical states + symbols (s) – solid (I) - liqud (g) – gas (aq) – aqueous ∆ - heating ppt – precipitate/solid ↔ - reversible
Calcium + hydrochloric → Calcium + carbon + water carbonate acid chloride dioxide
Reaction Stoichiometry • Quantitative relationship bet quantities of reactants/ products • Used to determine quantities/amt in (mass, moles, volume) • Predicts amt reactants react and amt products formed • Chemical reaction react in definite ratios
Chemical equation
Molecular equation
1CaCO3(s) + 2HCI(aq) → 1CaCI2(aq) + 1CO2(g) + 1H2O(l)
Reactants – Left side Products – Right side
Conservation Mass Total Mass reactants = Total Mass products
Mole Ratio (stoichiometric ratio) Coefficient in front of reactants/products - moles
1 : 2 → 1 : 1 : 2
Video on conservation mass
Before After
Chemical reaction • Matter is neither created nor destroyed • Undergoes physical and chemical change. • LAW of conservation of mass.
Chemical Reaction
Word equation
Chemical equation
Molecular equation
Reactants – Left side Products – Right side
Conservation Mass Total Mass reactants = Total Mass products
Mole Ratio (stoichiometric ratio) Coefficient in front of reactants/products - moles
Lead + Potassium → Lead + Potassium Nitrate iodide iodide nitrate
1Pb(NO3)2(aq) + 2KI(aq) → 1PbI2(s) + 2KNO3(aq)
1Pb(NO3)2(aq) + 2KI(aq) → 1PbI2(s) + 2KNO3(aq)
Mass of reactants (PbNO3 + KI) = 15.82
Mass of products (PbI3 + KNO3) = 15.82
After Before
Video on conservation mass 1 : 2 → 1 : 2
2H2 + 2I2 → 4HI 3NO2 + 3NO2 → 3N2O4
4g H2 508g I2 512g HI 150g NO2 300g N2O4
Simulation on conservation mass/balancing equation
Click to view animation
+
2 moles H2 2 moles I2 4 moles HI
Simulation on Chembalancer
150g NO2
3 moles NO2 3 moles NO2 3 moles N2O4
+ + +
Cations/Metals/+ve ions
Gp 1 Gp 2 Gp 3 Transition metals ions ( variable oxidation states)
Oxidation state
+1
Oxidation
state
+2
Oxidation state
+3
Sc +3
Ti +2 +3
V +2 +3
Cr +2 +3 +6
Mn +2 +3 +6 +7
Fe +2 +3
Co +2 +3
Ni +2
Cu +1 +2
Zn +2
Li 1+ Be2+ Sc 3+ Ti 2+
Ti 3+
V 2+
V 3+
Cr 2+
C r3+
Cr6+
Mn 2+
Mn 3+
Mn 6+
Mn 7+
Fe 2+
Fe 3+
Co2+
Co 3+
Ni2+ Cu1+
Cu2+
Zn2+
Na 1+ Mg2+ Al 3+
K 1+ Ca2+
Anion/Non metal
Gp 5 Gp 6 Gp 7
Oxidation state
Oxidation state
Oxidation state
-3 -2 -1
N3- O2- F-1
P3- S2- CI-1
Br-1
I-1
Metal/Cations/+ve ions
Non Metal/ Anions/ -ve ions
Ionic Compound
Li2O MgCI2 Al2O3 FeO Iron(II) oxide
NiO Nickel(II) oxide
CuO Copper(II) oxide
Li3N Mg3N2 AlN Fe3N2
Iron(II) nitride Ni3N2
Nickel(II) nitride Cu3N2
Copper(II) nitride
Oxidation state/Charge ion → Li1+ O2-
Formula compound Li
2 O
1
Video on polyatomic ions
Writing Chemical Formula
Step 1 : Write Oxidation state/charge
Step 2 : Balance it, (electrically neutral)
by cross multiply – as subscript
Polyatomic ions
Group of non-metals bonded together
Oxidation state
Oxidation state
Oxidation state
-1/+1 -2 -3
(OH)-1
Hydroxide (SO4)2-
Sulphate (PO4)3-
Phosphate
(CN)-1
Cyanide (SO3)2-
Sulphite
(SCN)-1
Thiocyanate (CO3)2-
Carbonate
(NO3)-1
Nitrate (S2O3)2-
Thiosulphate
(NO2)-1
Nitrite (Cr2O7)2-
Dichromate
(NH4)+1
Ammonium
Polyatomic ions
Li2(CO3) Mg(CO3) Al2(CO3)3 Fe(CO3) Ni(CO3) Cu(CO3)
Li(OH) Mg(OH)2 Al(OH)3 Fe(OH)2 Ni(OH)2 Cu(OH)2
Li2(SO4) Mg(SO4) Al2(SO4)3 FeSO4 Ni(SO4) Cu(SO4) Video on polyatomic ions
Ionic Compound
Writing Chemical Formula
Metal/Cations/+ve ions
Cations/Metals/+ve ions
Gp 1 Gp 2 Gp3 Transition metals ions ( variable oxidation states)
Oxidation state
+1
Oxidation state
+2
Oxidation state
+3
Sc +3
Ti +2 +3
V +2 +3
Cr +2 +3 +6
Mn +2 +3 +6 +7
Fe +2 +3
Co +2 +3
Ni +2
Cu +1 +2
Li 1+ Be2+ Sc 3+ Ti 2+
Ti 3+
V 2+
V 3+
Cr 2+
C r3+
Cr6+
Mn 2+
Mn 3+
Mn 6+
Mn 7+
Fe 2+
Fe 3+
Co2+
Co3+
Ni2+ Cu1+
Cu2+
Na 1+ Mg2+ Al 3+
K 1+ Ca2+
Oxidation state/Charge ion→ Li1+ (CO3)2-
Formula compound Li
2 (CO
3)1
Step 1 : Write Oxidation state/charge ion
Step 2 : Balance it, (electrically neutral)
by cross multiply – as subscript
Acids Alkali Metal Hydroxide
Metal oxides Salts Gas
HCI Hydrochloric acid
KOH Potassium hydroxide
CuO Copper(II) oxide
CaCO3
Calcium carbonate CO
Carbon monoxide
HNO3
Nitric acid NaOH
Sodium hydroxide MgO
Magnesium oxide Na2CO3
Sodium carbonate CO2
Carbon dioxide
H2SO3
Sulphurous acid Ca(OH)2
Calcium Hydroxide ZnO
Zinc oxide NaHCO3
Sodium bicarbonate SO2
Sulphur dioxide
HCOOH Methanoic acid
NH3
Ammonia Na2O
Sodium oxide KNO3
Potassium nitrate SO3
Sulphur trioxide
CH3COOH Ethanoic acid
Mg(OH)2
Magnesium hydroxide Al2O3
Aluminium oxide Pb(NO3)2
Lead (II) Nitrate NO2
Nitrogen dioxide
H3PO4
Phosphoric acid Cu(OH)2
Copper (II) hydroxide Fe2O3
Iron(III) oxide NaNO3
Sodium nitrate CH4
Methane
H2CO3
Carbonic acid Al(OH)3
Aluminium hydroxide K2S
Potassium sulphide PbI2
Lead (II) nitrate H2S
Hydrogen sulphide
HNO2
Nitrous acid Fe(OH)2
Iron (II) hydroxide PbS
Lead(II) sulphide AgCI
Silver chloride O2
Oxygen
HF Hydrofluoric acid
Fe(OH)3
Iron (III) hydroxide ZnS
Zinc sulphide MgSO4
Magnesium sulphate N2
Nitrogen
HCIO Hypochlorous acid
Zn(OH)2
Zinc hydroxide AI2S3
Aluminium sulphide Na2S2O3
Sodium thiosulphate CI2
Chlorine
Chemical Formula for common chemicals
Naming chemical compound Writing chemical formula Writing chemical formula
VIDEO TUTORIALS
Chemical Equation
Chemical Reaction/Change
Complete ionic equation
Molecular equation
Net ionic equation
1Pb(NO3)2(aq) + 2NaCI(aq) → 1PbCI2(s) + 2NaNO3(aq)
1Pb2+(aq) + 2NO3
-(aq) + 2Na+
(aq) + 2CI-(aq) → 1PbCI2(s) + 2Na+
(aq) + 2NO3-(aq)
Molecular equation
Complete ionic
equation
Net ionic equation
unchanged
1Pb2+(aq) + 2CI-
(aq) → 1PbCI2(s)
1Pb2+(aq) + 2NO3
-(aq) + 2Na+
(aq) + 2CI-(aq) → 1PbCI2(s )+ 2Na+
(aq) + 2NO3-(aq)
Break
aq → ions
Break
aq → ions
Break
aq → ions
Cancel out Cancel out
Video on ionic equation
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
• Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
Chemical Equation
Chemical Reaction/Change
Complete ionic equation
Molecular equation
Net ionic equation
Molecular equation
Complete ionic
equation
Net ionic equation
unchanged Break
aq → ions
Break
aq → ions Break
aq → ions
Cancel out Cancel out
Na2CO3(aq) + 2HNO3(aq) → 2NaNO3(aq) + H2O(l) + CO2(g)
2Na+(aq) + CO3
2-(aq) + 2H+
(aq) + 2NO3-(aq) → 2Na+
(aq) + 2NO3-(aq) + H2O(l) + CO2 (g)
CO32-
(aq) + 2H+(aq) → H2O(l) + CO2(g)
2Na+(aq) + CO3
2-(aq) + 2H+
(aq) + 2NO3-(aq) → 2Na+
(aq) + 2NO3-(aq) + H2O(l) + CO2 (g)
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
Click here for extra notes Click for here questions and answers to ionic equation Great link to simulation on stoichiometry. Click here.
Chemical Equation
Chemical Reaction/Change
Complete ionic equation
Molecular equation
Net ionic equation
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
Molecular equation
Complete ionic
equation
Net ionic equation
unchanged Break
aq → ions
Break
aq → ions
Break
aq → ions
Cancel out Cancel out
2 Na3PO4(aq) + 3CaCI2(aq) → 6NaCI(aq) + Ca3(PO4)2(s)
6Na+(aq) + 2PO4
3-(aq) + 3Ca2
(aq) + 6CI-(aq) → 6Na+
(aq) + 6CI-(aq) + Ca3(PO4)2(s)
2PO43-
(aq) + 3Ca2+(aq) → Ca3(PO4)2(s)
6Na+(aq) + 2PO4
3-(aq) + 3Ca2
(aq) + 6CI-(aq) → 6Na+
(aq) + 6CI-(aq) + Ca3(PO4)2(s)
Click here for extra notes Click for here questions and answers to ionic equation Great link to simulation on stoichiometry. Click here.
Molecular equation
Complete ionic
equation
Net ionic equation
Cancel out Cancel out
Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
Zn(s) + Cu2+(aq) + SO4
2- (aq) → Zn2+
(aq) + SO42-
(aq) + Cu(s)
Zn (s) + Cu2+(aq) → Zn2+
(aq) + Cu(s)
Zn(s) + Cu2+(aq) + SO4
2- (aq) → Zn2+
(aq) + SO42-
(aq) + Cu(s)
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
Mg(s) + 2H+(aq) + 2Cl-
(aq) → Mg2+(aq) + 2Cl-
(aq) + H2(g)
Mg(s) + 2H+(aq) + 2Cl-
(aq) → Mg2+(aq) + 2Cl-
(aq) + H2(g)
Mg(s) + 2H+(aq) → Mg2+
(aq) + H2(g)
Molecular equation
Complete ionic
equation
Net ionic equation
Cancel out Cancel out
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
• Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
Ionic Equation
Molecular equation
Complete ionic
equation
Net ionic equation
Cancel out Cancel out
Molecular equation
Complete ionic
equation
Net ionic equation
K2SO4(aq) + BaCl2 (aq) → BaSO4(s) + 2KCl(aq)
2K+(aq) + SO4
2-(aq) + Ba2+
(aq) + 2Cl-(aq) → BaSO4(s) + 2K+
(aq) + 2Cl-(aq)
2K+(aq) + SO4
2-(aq) + Ba2+
(aq) + 2Cl-(aq) → BaSO4(s) + 2K+
(aq) + 2Cl-(aq)
SO42-
(aq) + Ba2+(aq) → BaSO4 (s)
2Na+(aq) + 2OH-
(aq) + 2H+(aq) + SO4
2-(aq) → 2Na+
(aq) + SO42-
(aq) + 2H2O(l)
2NaOH(aq) + H2SO4 (aq) → Na2SO4(aq) + 2H2O(l)
2Na+(aq) + 2OH-
(aq) + 2H+(aq) + SO4
2-(aq) → 2Na+
(aq) + SO42-
(aq) + 2H2O(l)
2OH-(aq) + 2H+
(aq) → 2H2O(l)
OH-(aq) + H+
(aq) → H2O(l)
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
Cancel out Cancel out
Ionic Equation
Molecular equation
Complete ionic
equation
Net ionic equation
Cancel out Cancel out
Molecular equation
Complete ionic
equation
Net ionic equation
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
• Spectators ions- don’t participate in rxn • Cancel out ions from both sides of eqn • Only ions involved in rxn
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
•Break down electrolytes, (aq) → ions • Leave solid, liquid, gas unchanged
3(NH4)2CO3(aq) + 2Al(NO3)3(aq) → 6NH4NO3(aq) + Al2(CO3)3(s)
6NH4+
(aq) + 3CO32-
(aq) + 2Al3+(aq) + 6NO3
-(aq) → 6NH4
+(aq) + 6NO3
-(aq) + Al2(CO3)3(s)
6NH4+
(aq) + 3CO32-
(aq) + 2Al3+(aq) + 6NO3
-(aq) → 6NH4
+(aq) + 6NO3
-(aq) + Al2(CO3)3(s)
3CO32-
(aq) + 2Al3+(aq) → Al2(CO3)3(s)
CaCl2 (aq) + Na2CO3(aq) → 2 NaCl(aq) + CaCO3(s)
Ca2+(aq)+ 2 Cl- (aq) + 2 Na+ (aq)+ CO3
2- (aq) -> 2 Na+(aq) + 2Cl-
(aq) + CaCO3 (s)
Ca2+(aq)+ 2Cl-
(aq) + 2Na+(aq)+ CO3
2-(aq) → 2Na+
(aq) + 2Cl-(aq) + CaCO3 (s)
Ca2+(aq) + CO3
2-(aq) → CaCO3 (s)
Ionic Equation
Cancel out Cancel out
1Pb(NO3)2(s) + 2KI(aq) → 1PbI2(s) + 2KNO3 (aq)
Balanced Chemical equation
Coefficient • Mole proportion/ratio •(reactant) → (product) 1 : 2 → 1 : 2
Concept Map
Chemical Reaction
Chemical Equation
Molecular Equation
Complete Ionic Equation
Net Ionic Equation
1Pb2+(aq) + 2NO3
-(aq) + 2K+
(aq) + 2I-(aq) → 1PbI2(s) + 2K+
(aq) + 2 NO3-(aq)
1Pb2+(aq) + 2CI-
(aq) → 1PbCI2(s)
Chemical Change
leads to
represented by
1Pb(NO3)2(s) + 2KI(aq) → 1PbI2(s) + 2KNO3 (aq)
Stoichiometry • Quantitative relationship bet quantities of reactants/products • Determine quantities/amt in (mass, moles, volume) • Predicts amt reactants react and amt products formed • Chemical rxn reacts in definite ratios
Video on concept map above Simulation on stoichiometry Simulation on chembalancer
Exercise
Write balanced equation for the following reactions 1. Reaction of sulphur dioxide and oxygen to form sulphur trioxide 2SO2(g) + O2(g) → 2SO3(g)
2. Neutralization between potassium hydroxide and sulphuric acid to form potassium sulphate and water 2KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2H2O(I)
3. Combustion of ethane (C2H6) in air to form carbon dioxide and water 2C2H6(g) + 7O2(g ) → 4CO2(g) + 6H2O(I)
4. Displacement reaction between zinc metal and copper(II) sulphate solution to form copper metal and zinc sulphate Zn(s) + CuSO4(aq) → Cu(s) + ZnSO4(aq)
5. Decomposition of zinc carbonate to form zinc oxide and carbon dioxide when heated ZnCO3(s) → ZnO(s) + CO2(g)
6. Ammonia reacting with oxygen to form nitrogen monoxide and water. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(I)
7. Manganese(IV) oxide reacting with hydrochloric acid to form manganese(II) chloride solution, chlorine and water MnO2(s) + 4HCI(aq) → MnCI2(aq) + CI2(g) + 2H2O(I)
8. Neutralization between aqueous ammonia with hydrochloric acid to form ammonium chloride and water. NH4OH(aq) + HCI(aq) → NH4CI(aq) + H2O(I)
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