Question 1

For the chemical reaction A $\rarr$ C, a plot of 1/[A]t versus time was found to give a straight line with a positive slope. What is the order of reaction?

Accepted Answer

A) zeroth 
B) first 
C) second 
D) Such a plot cannot reveal the order of the reaction. 
A) zeroth 
B) first 
C) second 
D) Such a plot cannot reveal the order of the reaction.

Question 2

Complete the following statement: A catalyst

Accepted Answer

A) increases the activation energy. 
B) alters the reaction mechanism. 
C) increases the average kinetic energy of the reactants. 
D) increases the concentration of reactants. 
E) increases the collision frequency of reactant molecules. 
A) increases the activation energy. 
B) alters the reaction mechanism. 
C) increases the average kinetic energy of the reactants. 
D) increases the concentration of reactants. 
E) increases the collision frequency of reactant molecules.

Question 3

What is the rate law that corresponds to the data shown for the reaction 2A + B $\rarr$ C?

Accepted Answer

Rate = k[B

Question 4

The activation energy for the reaction O + O3 $\rarr$ 2O2 is 25 kJ/mol, and the enthalpy change is $\Delta$H = -388 kJ/mol. What is the activation energy for the decomposition of O2 by the reverse reaction?

Accepted Answer

A) 413 kJ 
B) 388 kJ 
C) 363 kJ 
D) 50 kJ 
E) 25 kJ 
A) 413 kJ 
B) 388 kJ 
C) 363 kJ 
D) 50 kJ 
E) 25 kJ

Question 5

At 700 K, the rate constant for the following reaction is 6.2 *10-4 min-1.   How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

Accepted Answer

A) 1,120 min 
B) 360 min 
C) 3710 min 
D) 1.4 * 10-4 min 
E) 280 min 
A) 1,120 min 
B) 360 min 
C) 3710 min 
D) 1.4 * 10-4 min 
E) 280 min

Question 6

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B $\rarr$ products?

Accepted Answer

A) increasing the concentration of A 
B) increasing the concentration of B 
C) increasing the temperature 
D) measuring k again after the reaction has run for a while 
A) increasing the concentration of A 
B) increasing the concentration of B 
C) increasing the temperature 
D) measuring k again after the reaction has run for a while

Question 7

The following reaction in aqueous solution was found to be first order in [OH-], first order in [C2H5Br], and inverse first order in Br-.
C2H5Br + OH-  $\rarr$ C2H5OH + Br- 
 Which one of the following mechanisms is consistent with the observed reaction order?

Accepted Answer

A) C2H5Br $\rarr$ C2H5+ + Br- - fast C2H5+ + OH- $\rarr$ C2H5OH slow 
B) C2H5Br +H2O $\rarr$C2H5OH + H+ + Br-  slow H+ + OH- $\rarr$ H2O fast 
C) C2H5Br $\rarr$C2H5+ + Br- slow C2H5+ + OH- $\rarr$C2H5OH fast 
D) C2H5Br $\rarr$ C2H5+ + Br-  slow OH- + Br-  $\rarr$ HOBr fast
HOBr + C2H5+ $\rarr$ C2H5OH + Br- fast 
A) C2H5Br $\rarr$ C2H5+ + Br- - fast C2H5+ + OH- $\rarr$ C2H5OH slow 
B) C2H5Br +H2O $\rarr$C2H5OH + H+ + Br-  slow H+ + OH- $\rarr$ H2O fast 
C) C2H5Br $\rarr$C2H5+ + Br- slow C2H5+ + OH- $\rarr$C2H5OH fast 
D) C2H5Br $\rarr$ C2H5+ + Br-  slow OH- + Br-  $\rarr$ HOBr fast
HOBr + C2H5+ $\rarr$ C2H5OH + Br- fast

Question 8

At a particular temperature the first-order gas-phase reaction 2N2O5 $\rarr$2N2O4 + O2 has a half-life for the disappearance of dinitrogen pentoxide of 3240 s. If 1.00 atm of N2O5 is introduced into an evacuated 5.00 L flask, what will be the total pressure of the gases in the flask after 1.50 hours?

Accepted Answer

A) 0.685 atm 
B) 1.00 atm 
C) 0.315 atm 
D) 1.68 atm 
E) 1.34 atm 
A) 0.685 atm 
B) 1.00 atm 
C) 0.315 atm 
D) 1.68 atm 
E) 1.34 atm

Question 9

The thermal decomposition of acetaldehyde, CH3CHO $\rarr$CH4 + CO, is a second-order reaction. The following data were obtained at 518°C.   Calculate the rate constant for the decomposition of acetaldehyde from the above data.

Accepted Answer

A) 2.2 * 10-3/s 
B) 0.70 mmHg/s 
C) 2.2 * 10-3/mmHg·s 
D) 6.7 * 10-6/mmHg·s 
E) 5.2 * 10-5/mmHg·s 
A) 2.2 * 10-3/s 
B) 0.70 mmHg/s 
C) 2.2 * 10-3/mmHg·s 
D) 6.7 * 10-6/mmHg·s 
E) 5.2 * 10-5/mmHg·s

Question 10

For the reaction represented below, the experimental rate law is given by rate = k [(CH3)3CCl]. (CH3)3CCl(aq)+ OH- $\rarr$(CH3)3COH(aq)+ Cl- 
 If some solid sodium hydroxide were added to a solution in which [(CH3)3CCl] = 0.01 M and
[NaOH] = 0.10 M, which of the following would be true? (Assume the temperature and volume remain constant.)

Accepted Answer

A) Both the reaction rate and k would increase. 
B) Both the reaction rate and k would decrease. 
C) Both the reaction rate and k would remain the same. 
D) The reaction rate would increase but k would remain the same. 
E) The reaction rate would decrease but k would remain the same. 
A) Both the reaction rate and k would increase. 
B) Both the reaction rate and k would decrease. 
C) Both the reaction rate and k would remain the same. 
D) The reaction rate would increase but k would remain the same. 
E) The reaction rate would decrease but k would remain the same.

Question 11

Nitrogen pentoxide decomposes by a first-order process yielding N2O4 and oxygen.
2N2O5 $\rarr$ 2N2O4 + O2
 At a given temperature, the half-life of N2O5 is 0.90 hr. What is the first-order rate constant for N2O5 decomposition?

Accepted Answer

0.77 hr<su

Question 12

Which of the following statements is false?

Accepted Answer

A) A catalyst increases the rate of the forward reaction, but does not alter the reverse rate. 
B) A catalyst alters the mechanism of reaction. 
C) A catalyst alters the activation energy. 
D) A catalyst may be altered in the reaction, but is always regenerated. 
E) A catalyst increases the rate of reaction, but is not consumed. 
A) A catalyst increases the rate of the forward reaction, but does not alter the reverse rate. 
B) A catalyst alters the mechanism of reaction. 
C) A catalyst alters the activation energy. 
D) A catalyst may be altered in the reaction, but is always regenerated. 
E) A catalyst increases the rate of reaction, but is not consumed.

Question 13

For the following exothermic reaction, the rate law at 298 K is rate = k [H2][I2].
H2(g)+ I2(g)$\rarr$ 2HI(g)
Predict the effect of each of the following changes on the initial rate of the reaction:
a. Addition of hydrogen gas at constant temperature and volume
b. Increase in volume of the reaction vessel at constant temperature
c. Addition of a catalyst
d. Increase in temperature

Accepted Answer

a. The initial rate increases.

Question 14

At 30°C, by how much is a reaction's activation energy decreased by the addition of a catalyst if the catalyst triples the reaction rate?

Accepted Answer

A) 2.77 kJ/mol 
B) 274 J/mol 
C) 2.70 J/mol 
D) 119 J/mol 
E) 1.20 kJ/mol 
A) 2.77 kJ/mol 
B) 274 J/mol 
C) 2.70 J/mol 
D) 119 J/mol 
E) 1.20 kJ/mol

For the chemical reaction A $\rarr$ C, a plot of 1/[A]_t versus time was found to give a straight line with a positive slope. What is the order of reaction?

Complete the following statement: A catalyst

What is the rate law that corresponds to the data shown for the reaction 2A + B $\rarr$ C? $What is the rate law that corresponds to the data shown for the reaction 2A + B \rarr C?$

The activation energy for the reaction O + O₃ $\rarr$ 2O₂ is 25 kJ/mol, and the enthalpy change is $\Delta$ H = -388 kJ/mol. What is the activation energy for the decomposition of O₂ by the reverse reaction?

At 700 K, the rate constant for the following reaction is 6.2 *10^-4 min^-1. How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B $\rarr$ products?

The following reaction in aqueous solution was found to be first order in [OH^-], first order in [C₂H₅Br], and inverse first order in Br^-. C₂H₅Br + OH^- $\rarr$ C₂H₅OH + Br^- Which one of the following mechanisms is consistent with the observed reaction order?

Nitrogen pentoxide decomposes by a first-order process yielding N₂O₄ and oxygen. 2N₂O₅ $\rarr$ 2N₂O₄ + O₂ At a given temperature, the half-life of N₂O₅ is 0.90 hr. What is the first-order rate constant for N₂O₅ decomposition?

Which of the following statements is false?

At 30°C, by how much is a reaction's activation energy decreased by the addition of a catalyst if the catalyst triples the reaction rate?

Introduction

Atoms, Molecules, and Ions

Stoichiometry

Reactions in Aqueous Solution

Gases

Energy Relationships in Chemical Reactions

The Electronic Structure of Atoms

The Periodic Table

Chemical Bonding I: the Covalent Bond

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Introduction to Organic Chemistry

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Thermodynamics

Redox Reactions and Electrochemistry

The Chemistry of Coordination Compounds

Nuclear Chemistry

Organic Polymerssynthetic and Natural

Filters

Exam 14: Chemical Kinetics

For the chemical reaction A →\rarr→ C, a plot of 1/[A]t versus time was found to give a straight line with a positive slope. What is the order of reaction?

Complete the following statement: A catalyst

What is the rate law that corresponds to the data shown for the reaction 2A + B →\rarr→ C?

The activation energy for the reaction O + O3 →\rarr→ 2O2 is 25 kJ/mol, and the enthalpy change is Δ\DeltaΔ H = -388 kJ/mol. What is the activation energy for the decomposition of O2 by the reverse reaction?

At 700 K, the rate constant for the following reaction is 6.2 *10-4 min-1. How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B →\rarr→ products?

The following reaction in aqueous solution was found to be first order in [OH-], first order in [C2H5Br], and inverse first order in Br-. C2H5Br + OH- →\rarr→ C2H5OH + Br- Which one of the following mechanisms is consistent with the observed reaction order?

The thermal decomposition of acetaldehyde, CH3CHO →\rarr→ CH4 + CO, is a second-order reaction. The following data were obtained at 518°C. Calculate the rate constant for the decomposition of acetaldehyde from the above data.

Nitrogen pentoxide decomposes by a first-order process yielding N2O4 and oxygen. 2N2O5 →\rarr→ 2N2O4 + O2 At a given temperature, the half-life of N2O5 is 0.90 hr. What is the first-order rate constant for N2O5 decomposition?

Which of the following statements is false?

At 30°C, by how much is a reaction's activation energy decreased by the addition of a catalyst if the catalyst triples the reaction rate?

Introduction

Atoms, Molecules, and Ions

Stoichiometry

Reactions in Aqueous Solution

Gases

Energy Relationships in Chemical Reactions

The Electronic Structure of Atoms

The Periodic Table

Chemical Bonding I: the Covalent Bond

Chemical Bonding Ii: Molecular Geometry and Hybridization of Atomic Orbitals

Introduction to Organic Chemistry

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Thermodynamics

Redox Reactions and Electrochemistry

The Chemistry of Coordination Compounds

Nuclear Chemistry

Organic Polymerssynthetic and Natural

Filters

For the chemical reaction A $\rarr$ C, a plot of 1/[A]_t versus time was found to give a straight line with a positive slope. What is the order of reaction?

What is the rate law that corresponds to the data shown for the reaction 2A + B $\rarr$ C? $What is the rate law that corresponds to the data shown for the reaction 2A + B \rarr C?$

The activation energy for the reaction O + O₃ $\rarr$ 2O₂ is 25 kJ/mol, and the enthalpy change is $\Delta$ H = -388 kJ/mol. What is the activation energy for the decomposition of O₂ by the reverse reaction?

At 700 K, the rate constant for the following reaction is 6.2 *10^-4 min^-1. How many minutes are required for 20% of a sample of cyclopropane to isomerize to propene?

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B $\rarr$ products?

The following reaction in aqueous solution was found to be first order in [OH^-], first order in [C₂H₅Br], and inverse first order in Br^-. C₂H₅Br + OH^- $\rarr$ C₂H₅OH + Br^- Which one of the following mechanisms is consistent with the observed reaction order?

Nitrogen pentoxide decomposes by a first-order process yielding N₂O₄ and oxygen. 2N₂O₅ $\rarr$ 2N₂O₄ + O₂ At a given temperature, the half-life of N₂O₅ is 0.90 hr. What is the first-order rate constant for N₂O₅ decomposition?