1011ExamPrepWorksheet.doc Chapter 19.1 Balancing Redox Equations Chapter 19.1 Multiple Choice 1) What is the oxidation number of phosphorus in (NH 4 )H 3 P 2 O 7 ? a) +7 b) +6 c) +5 d) +4 e) +3 Chapter 19.1 Longer answer 1) Balance the following redox reaction in basic solution. SO 4 2− (aq) + I − (aq) → I 2 (aq) + H 2 S(aq) 2) Consider the following reaction: As 2 O 3 (s) + MnO 4 - (aq) → H 3 AsO 4 (aq) + Mn 2+ (aq) a) Identify the oxidation number of As in As 2 O 3 . b) Which species is being reduced? c) Balance the above reaction in acidic solution. 3) Balance the following redox skeleton equation in basic solution: Fe 2+ (aq) + Cr 2 O 7 2- (aq) → Fe 3+ (aq) + Cr 3+ (aq) Chapter 9 Ionic and Covalent Bonding Chapter 9 Multiple Choice 1) The nitrogen–hydrogen bond in a molecule of ammonia is an example of what type of bond? a) ionic bond b) non-polar covalent bond c) polar covalent bond d) hydrogen bond e) none of the above 2) A triple bond is generally composed of a) three π bonds b) two π bonds and one σ bond c) one π bond and two σ bonds d) three σ bonds e) none of the above describes a triple bond. 3) Xenon atoms in a compound like XeF 4 can be shown to have sp 3 d 2 hybrid orbitals. How many of these sp 3 d 2 hybrid orbitals are there associated with Xe? a) 2 b) 4 c) 6 d) 8 Chapter 10 Molecular Geometry Chapter 10 Multiple Choice 1) Which of the following statements is FALSE for sp 3 hybridized orbitals? a) They are formed from the combination of one s orbital and three p orbitals. b) There are four sp 3 orbitals. c) When an element has sp 3 hybridization it can form 4 single bonds with other atoms. d) The angle between bonds in a molecule whose central atom has sp 3 hybridization is 90 o . e) sp 3 hybridization gives water its bent geometry - 1 -
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1011ExamPrepWorksheet.doc
Chapter 19.1 Balancing Redox Equations Chapter 19.1 Multiple Choice 1) What is the oxidation number of phosphorus in (NH4)H3P2O7?
a) +7 b) +6 c) +5 d) +4 e) +3
Chapter 19.1 Longer answer 1) Balance the following redox reaction in basic solution.
SO42−(aq) + I−(aq) → I2(aq) + H2S(aq)
2) Consider the following reaction:
As2O3 (s) + MnO4- (aq) → H3AsO4 (aq) + Mn2+ (aq)
a) Identify the oxidation number of As in As2O3.
b) Which species is being reduced?
c) Balance the above reaction in acidic solution.
3) Balance the following redox skeleton equation in basic solution:
Fe2+ (aq) + Cr2O72- (aq) → Fe3+ (aq) + Cr3+ (aq)
Chapter 9 Ionic and Covalent Bonding Chapter 9 Multiple Choice 1) The nitrogen–hydrogen bond in a molecule of ammonia is an example of what
type of bond?
a) ionic bond b) non-polar covalent bond c) polar covalent bond
d) hydrogen bond e) none of the above
2) A triple bond is generally composed of
a) three π bonds b) two π bonds and one σ bond
c) one π bond and two σ bonds d) three σ bonds
e) none of the above describes a triple bond.
3) Xenon atoms in a compound like XeF4 can be shown to have sp3d2 hybrid
orbitals. How many of these sp3d2 hybrid orbitals are there associated with Xe?
a) 2 b) 4 c) 6 d) 8
Chapter 10 Molecular Geometry Chapter 10 Multiple Choice 1) Which of the following statements is FALSE for sp3 hybridized orbitals?
a) They are formed from the combination of one s orbital and three p orbitals.
b) There are four sp3 orbitals.
c) When an element has sp3 hybridization it can form 4 single bonds with
other atoms.
d) The angle between bonds in a molecule whose central atom has sp3
hybridization is 90o.
e) sp3 hybridization gives water its bent geometry
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1011ExamPrepWorksheet.doc
Chapter 10 Shorter Answer 1) The molecule methyl cyanoacrylate, shown below, is used to make polymers.
Specify the type of hybridization of the carbon atoms labeled X, Y and Z.
H2C C
C
N
O
OCH3
ZX
Y
2) Write the two electron-dot resonance structures for the molecule SeO2.
3) What is the hybridization of N in the molecule F-N=N-F?
4) Briefly, but completely, explain or define hybrid orbitals.
Chapter 11 States of Matter Chapter 11 Multiple choice 1) Which of the following is a covalent network solid?
a) Diamond b) Calcium c) Calcium chloride
d) Iodine e) Sucrose
2) Krypton has a higher melting point than argon because it has
a) Hydrogen bonding b) Ionic bonds
c) A permanent dipole moment d) Stronger dispersion forces
e) A greater ionization energy
3) Which statement is most true about an ionic solid?
a) It is soft and has a low melting point.
b) It is hard and has a low melting point.
c) It is soft and has a high melting point.
d) It is hard and has a high melting point.
4) A crystalline solid of unknown origin melts to form a liquid that conducts an
electrical current. The solid also has a high melting point and shatters when
struck by a hammer. The solid is most likely to be
a) an ionic solid. b) a covalent network sold.
c) a molecular solid. d) a metallic solid.
5) Which of the intermolecular forces is the most important contributor to the high
melting point of water?
a) dipole-dipole forces b) dispersion forces
c) hydrogen bonding d) ion-dipole forces
6) In which substance would the London dispersion forces be weakest?
a) Ne b) Ar c) Kr d) Xe
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1011ExamPrepWorksheet.doc
7) Which of the listed intermolecular forces is most likely to be the strongest?
a) dipole-dipole forces
b) hydrogen bonds
c) London dispersion forces
d) all three listed forces will have relatively the same strength
8) Of the following four molecules, which molecules would we expect to be polar?
CF4 PF3 H2O HF
a) All of these molecules are polar.
b) All of the molecules are polar except for CF4.
c) Only PF3 and H2O are polar.
d) None of these molecules are polar.
Chapter 11 Shorter Answer 1) The strongest intermolecular force that occurs between two NH3 molecules is
(ion-dipole, dipole-dipole, London dispersion, hydrogen bonding). Choose the
correct phrase in brackets and briefly explain your answer.
2) What is the difference between dipole-dipole forces and London dispersion
forces?
3) Identify the likely kind of intermolecular forces present in each of the following:
methanol, CH3OH
hydrogen chloride, HCl
chloromethane, CH3Cl
oxygen, O2
4) Place the following compounds, methyl alcohol, CH3OH, oxygen, O2, and
hydrogen chloride, HCl, in order of increasing melting point.
5) Draw three possible Lewis dot structures for OCN-. Be sure to show the formal
charges for each structure. Circle the best possible Lewis dot structure of the
three.
6) Define molecular solid.
7) Briefly, but completely, explain or define covalent network solid.
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1011ExamPrepWorksheet.doc
Chapter 11 Longer Answer 1) Complete the following table:
Species
OF2
PBr5
IF4
−
Lewis electron dot structure
Sketch of the 3- dimensional
shape
Name of the
molecular shape
Approximate bond angles
2) Below is a list of four molecules.
a) For each molecule list ALL possible intermolecular forces that occur between
two of the same molecules.
H2S [34 g·mol-1] CH3OH [32 g·mol-1]
C2H6 [30 g·mol-1] Ne [20 g·mol-1]
b) Based on your answers in part a), rank the molecules in order of lowest boiling
point to highest boiling point.
c) Draw the Lewis dot structure for H2S and name both the electron distribution
shape and the molecular geometry.
Chapter 13 Rates of Reaction Chapter 13 Multiple choice 1) What are the units of the rate constant for the following rate law?
Rate = k[A]2[B]1[C]0
a) L ⋅mol ⋅s2 -2 -1 b) L⋅mol-1⋅s-1 c) L2⋅mol-2⋅s-2
d) L3⋅mol-3⋅s-1 e) mol3⋅L-3⋅s-1
2) The rate of a reaction is measured in mol⋅L-1⋅s-1. What are the units for the rate
constant if this reaction is a termolecular reaction?
a) s-1 b) mol2⋅L-2⋅s-1 c) L⋅mol-1⋅s-1
d) L2⋅mol-2⋅s-2 e) L2⋅mol-2⋅s-2
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1011ExamPrepWorksheet.doc
3) For a reaction that follows the rate law, rate = k[A][B]2, what will happen to the
rate of reaction if the concentration of A is increased by a factor of three and the
concentration of B is increased by a factor of 2?
a) increases by a factor of 3 b) increases by a factor of 4
c) increases by a factor of 6 d) increases by a factor of 12
4) The rate law for the reaction: 2 NO2 + O3 → N2O5 + O2 is rate = k[NO2][O3].
Which of the following mechanisms is consistent with this rate law?
a) 2 NO2 → N2O4 fast
N2O4 + O3 → N2O5 + O2 slow
b) NO2 + O3 → NO5 fast
2 NO5 → N2O5 + 5/2 O2 slow
c) NO2 + O3→ NO3 + O2 slow
NO3 + NO2 → N2O5 fast
d) 2 NO2→ N2O2 + O2 slow
N2O2 + O3 → N2O5 fast
5) The units for a first order rate constant are:
a) mol⋅L-1⋅s-1 b) L⋅mol-1⋅s-1 c) s-1 d) L2⋅mol-2⋅s-1
6) Ozone decomposes to oxygen according to the equation: 2 O3(g) → 3 O2(g). If
the rate at which O2 appears is 6.0 x 10-5 mol⋅s-1 at a particular instant, what is
the-rate of disappearance of O3 at the same instant?
a) 6.0 x 10-5 mol/s b) 4.0 x 10-5 mol⋅s-1 c) 9.0 x 10-5 mol⋅s-1
d) 12 x10-5 mol⋅s-1
7) Which of the following statements about a catalyst are true?
a) A catalyst changes the position of equilibrium in a reaction
b) a catalyst increases the temperature of a reaction
c) a catalyst is consumed in a chemical reaction
d) a catalyst provides a lower energy pathway for a reaction
8) What factor affects the rate of a chemical reaction?
a) activation energy b) net energy c) potential energy d) rate limiting energy
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1011ExamPrepWorksheet.doc
9) Which of the following four statements are TRUE about reaction mechanisms?
I ) A rate law can be written from the molecularity of the slowest
elementary step
II ) A final rate law can include intermediates
III) The rate of reaction is dependent on the fastest step in the mechanism
IV) A mechanism can never be proven to be the correct pathway for a
reaction
a) I, II, III b) II, IV c) I, III d) I, IV
10) The decomposition of dinitrogen pentaoxide is described by the chemical
equation: 2 N2O5 (g) → 4 NO (g) + O2 (g). If the rate of appearance of O2 is
1.20 mol⋅L-1⋅min-1 at a particular moment, what is the rate of disappearance of
N2O5 at that same moment?
a) 4.80 mol⋅L-1⋅min-1 b) 1.20 mol⋅L-1⋅min-1 c) 2.40 mol⋅L-1⋅min-1
d) -1.20 mol⋅L-1⋅min-1
11) “Instantaneous rate” is defined as the
a) change in concentration per unit time
b) equation showing how the rate depends on the concentration of each reactant
c) rate of reaction at a particular time
d) rate of reaction during a particular time interval
12) What factor affects the rate of a chemical reaction?
a) collision frequency
b) fraction of molecules with sufficient energy
c) orientation of molecules in the collision
d) all of the above
13) The decomposition of ozone in the stratosphere can occur by the following two-
step mechanism:
Br + O3 → BrO + O2
BrO + O → Br + O2
Which statement is true for the mechanism?
a) BrO is a catalyst; Br is a reaction intermediate.
b) BrO is a reaction intermediate; Br is a reaction intermediate.
c) BrO is a reaction intermediate; Br is a catalyst.
d) BrO is a catalyst; Br is a catalyst.
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1011ExamPrepWorksheet.doc
14) The pre-exponential factor, A, in the Arrhenius equation, k = A e-(Ea/RT), can be
broken down into the:
a) collision frequency z and the fraction of collisions of sufficient energy f. b) steric factor p and the fraction of collisions of sufficient energy f. c) collision frequency z and the steric factor p.
d) collision frequency z, the steric factor p, and the fraction of collisions of
sufficient energy f. 15) A given reaction forms A as a product. If in the time interval between 300
seconds and 400 seconds ∆[A] / ∆ t = 3.7 x 10-5 mol⋅L-1⋅s-1, then which statement
is most true for the time interval between 700 and 800 seconds?
a) ∆[A] / ∆ t < 3.7 x 10-5 mol⋅L-1⋅s-1
b) ∆[A] / ∆ t = 3.7 x 10-5 mol⋅L-1⋅s-1
c) ∆[A] / ∆ t > 3.7 x 10-5 mol⋅L-1⋅s-1
d) ∆[A] / ∆ t = 0.0 mol⋅L-1⋅s-1
16) Which statement is true about the orders of a reaction?
a) The order with respect to a given reactant is always the same as the
stoichiometric coefficient in the balanced equation.
b) The overall order of the reaction can be found by multiplying the orders with
respect to each reactant.
c) The orders with respect to the reactants must be determined experimentally.
d) The orders must be positive integers.
17) Increasing the temperature of a chemical reaction by ten degrees Celcius
approximately doubles the rate of the reaction. This is primarily because:
a) more collisions occur with sufficient energy to reach the transition state.
b) the number of collisions between molecules doubles.
c) the activation energy increases.
d) the activation energy decreases.
18) Which statement is most true about reaction intermediates and catalysts?
a) Both are consumed in an early elementary step and are reformed in a later
elementary step.
b) Both are formed in an early elementary step and are consumed in a later
elementary step.
c) Catalysts are formed in early elementary steps and are consumed in later steps.
Reaction intermediates are consumed in early steps and are reformed in later
steps.
d) Reaction intermediates are formed in early elementary steps and are consumed
in later steps. Catalysts are consumed in early steps and are reformed in later
steps.
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1011ExamPrepWorksheet.doc
19) A mechanism for a naturally occurring reaction that destroys ozone is
Step 1: O3 (g) + HO (g) → HO2 (g) + O2 (g)
Step 2: HO2 (g) + O (g) → HO (g) + O2 (g)
Which species is a catalyst and what type of catalysis is occurring?
a) HO, homogeneous b) HO, heterogeneous
c) HO2, homogeneous d) HO2, heterogeneous
20) Which of the following things can be done to guarantee an increase in the rate of
a reaction?
a) increasing the temperature.
b) increasing the concentration of a reactant.
c) neither a) or b) will guarantee an increase in the rate of a reaction.
d) both a) and b) will guarantee an increase in the rate of a reaction.
21) Which of the following statements would be correct regarding the following
reaction?
2 H2 (g) + O2 (g) → 2 H2O (g)
a) The rate of H2 disappearance is twice the rate of O2 disappearance.
b) The rate of H2O appearance is equal to the rate of O2 disappearance.
c) The rate of H2O disappearance is twice the rate of O2 appearance.
d) The rate of O2 disappearance is twice the rate of H2 disappearance.