Question 1

The graphs below all refer to the same reaction. What is the order of this reaction?

Accepted Answer

A) zeroth order 
B) first order 
C) second order 
D) unable to predict

Question 2

The rate constant for the first-order decomposition of C₄H₈ at 500°C is 9.2 * 10^-3 s^-1. How long will it take for 10.0% of a 0.100 M sample of C₄H₈ to decompose at 500°C?

Accepted Answer

The answer of The rate constant for the first-order decomposition...

Question 3

The Arrhenius equation is k = Ae-Ea/RT. The slope of a plot of ln k vs. 1/T is equal to

Accepted Answer

A) -k. 
B) k. 
C) Ea. 
D) -Ea /R. 
E) A.

Question 4

Sucrose, C₁₂H₂₂O₁₁, reacts slowly with water in the presence of an acid to form two other sugars, glucose and fructose, both of which have the same molecular formulas, but different structures. C₁₂H₂₂O₁₁ + H₂O $\rarr$ C₆H₁₂O₆ (glucose)+ C₆H₁₂O₆ (fructose) The reaction is first order and has a rate constant of 6.2 * 10^-5 /s at 35°C when the H⁺ concentration is 0.10 M. Suppose that the initial concentration of sucrose in the solution is 0.40 M. How many minutes will it take for the sucrose concentration to drop to 0.30 M?

Accepted Answer

The answer of Sucrose, C₁₂H₂₂O₁₁, reacts slowly with water in...

Question 5

In the reaction, 2N2O $\rarr$ 2N2 + O2, oxygen and nitrogen gases are formed at the same rate (mol/L·s).

Accepted Answer

A) True 
 B)False

Question 6

For the following reaction, $\Delta$P(C6H14)/$\Delta$t was found to be -6.2 * 10-3 atm/s. C6H14(g)$\rarr$ C6H6(g)+ 4H2(g)
Determine $\Delta$P(H2)/$\Delta$t for this reaction at the same time.

Accepted Answer

A) 6.2 * 10-3 atm/s 
B) 1.6 * 10-3 atm/s 
C) 2.5 * 10-2 atm/s 
D) -1.6 * 10-3 atm/s 
E) -2.5 * 10-2 atm/s

Question 7

For the chemical reaction system described by the diagram below, which statement is true?  If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is Ea for the reverse reaction?

Accepted Answer

A) 120 kJ/mol 
B) 70 kJ/mol 
C) 95 kJ/mol 
D) 25 kJ/mol 
E) -70 kJ/mol

Question 8

The isomerization of cyclopropane to propene follows first-order kinetics.  At 700 K, the rate constant for this reaction is 6.2 * 10-4 min-1. How many minutes are required for 10.0% of a sample of cyclopropane to isomerize to propene?

Accepted Answer

A) 16,100 min 
B) 170 min 
C) 3,710 min 
D) 1.43 * 10-3 min 
E) 1,120 min

Question 9

The reaction 2NO2(g)$\rarr$2NO(g)+ O2(g)is suspected to be second order in NO2. Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

Accepted Answer

A) a plot of [NO2]-1 vs. t 
B) a plot of ln [NO2] vs. t 
C) a plot of [NO2] vs. t 
D) a plot of ln [NO2]-1 vs. t 
E) a plot of [NO2]2 vs. t

Question 10

When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,

Accepted Answer

A) the average kinetic energy of molecules increases. 
B) the frequency of molecular collisions increases. 
C) the rate constant increases. 
D) the activation energy increases. 
E) the order of reaction increases.

Question 11

At a certain temperature, the data below were collected for the reaction below. 2ICl + H₂ $\rarr$I₂ + 2HCl. Determine the rate constant for the reaction.

Accepted Answer

The answer of At a certain temperature, the data below...

Question 12

The thermal decomposition of acetaldehyde, CH3CHO $\rarr$ CH4 + CO, is a second-order reaction. The following data were obtained at 518°C.  Based on the data given, what is the half-life for the disappearance of acetaldehyde?

Accepted Answer

A) 1.5 * 105 s 
B) 410 s 
C) 5.4 * 107 s 
D) 520 s 
E) 305 s

Question 13

A first-order reaction has a rate constant of 7.5 * 10-3 /s. The time required for the reaction to be 60% complete is

Accepted Answer

A) 3.8 * 10-3 s. 
B) 6.9 * 10-3 s. 
C) 68 s. 
D) 120 s. 
E) 130 s.

Question 14

Aspirin, C₉H₈O₄, slowly decomposes at room temperature by reacting with water in the atmosphere to produce acetic acid, HC₂H₃O₂, and 2-hydroxybenzoic acid, C₇H₆O₃ (this is why old bottles of aspirin often smell like vinegar): C₉H₈O₄ + H₂O $\rarr$HC₂H₃O₂ + C₇H₆O₃ Concentration and rate data for this reaction are given below. Write the rate law for this reaction and calculate k (be sure to include the correct units).

Accepted Answer

The answer of Aspirin, C₉H₈O₄, slowly decomposes at room temperature...

Question 15

A rate constant will have the units mol · L-1 · s-1 when the reaction is overall

Accepted Answer

A) zero order. 
B) first order. 
C) second order. 
D) third order. 
E) fourth order.

Question 16

A nuclear stress test utilizes a gamma-emitting radioisotope such as thallium-201 to follow the flow of blood through the heart - first at rest, and then under stress. The first-order rate constant for the decay of thallium-201 is 9.5 x 10^-3 hr^-1. Calculate how long it takes for the amount of thallium-201 to fall to 5.0% of its original value.

Accepted Answer

The answer of A nuclear stress test utilizes a gamma-emitting...

Question 17

For the chemical reaction system described by the diagram below, which statement is true?

Accepted Answer

A) The forward reaction is endothermic. 
B) The activation energy for the forward reaction is greater than the activation energy for the reverse reaction. 
C) At equilibrium, the activation energy for the forward reaction is equal to the activation energy for the reverse reaction. 
D) The activation energy for the reverse reaction is greater than the activation energy for the forward reaction. 
E) The reverse reaction is exothermic.

Question 18

A rate constant with the units L2 · mol-2 · s-1 is consistent with a

Accepted Answer

A) zero-order reaction. 
B) first-order reaction. 
C) second-order reaction. 
D) third-order reaction. 
E) fourth-order reaction.

Question 19

What is the slope of an Arrhenius plot for the following reaction? 2NOCl $\rarr$ 2NO + Cl2

Accepted Answer

A) 8.18 * 10-2 K 
B) 5.06 * 10-2 K 
C) -1.22 * 104 K 
D) -1.96 * 104 K 
E) not enough information to calculate the slope

Question 20

Appropriate units for a first-order rate constant are

Accepted Answer

A) M/s. 
B) 1/M·s. 
C) 1/s. 
D) 1/M2·s.

Exam 14: Chemical Kinetics

The graphs below all refer to the same reaction. What is the order of this reaction?

The rate constant for the first-order decomposition of C₄H₈ at 500°C is 9.2 * 10^-3 s^-1. How long will it take for 10.0% of a 0.100 M sample of C₄H₈ to decompose at 500°C?

The Arrhenius equation is k = Ae^-Ea/RT. The slope of a plot of ln k vs. 1/T is equal to

In the reaction, 2N₂O $\rarr$ 2N₂ + O₂, oxygen and nitrogen gases are formed at the same rate (mol/L·s).

For the following reaction, $\Delta$ P(C₆H₁₄) / $\Delta$ t was found to be -6.2 * 10^-3 atm/s. C₆H₁₄(g) $\rarr$ C₆H₆(g) + 4H₂(g) Determine $\Delta$ P(H₂) / $\Delta$ t for this reaction at the same time.

For the chemical reaction system described by the diagram below, which statement is true? If the E_a for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is E_a for the reverse reaction?

The isomerization of cyclopropane to propene follows first-order kinetics. At 700 K, the rate constant for this reaction is 6.2 * 10^-4min^-1. How many minutes are required for 10.0% of a sample of cyclopropane to isomerize to propene?

The reaction 2NO₂(g) $\rarr$ 2NO(g) + O₂(g) is suspected to be second order in NO₂. Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,

A first-order reaction has a rate constant of 7.5 * 10^-3/s. The time required for the reaction to be 60% complete is

A rate constant will have the units mol · L^-1 · s^-1 when the reaction is overall

For the chemical reaction system described by the diagram below, which statement is true?

A rate constant with the units L² · mol^-2 · s^-1 is consistent with a

Appropriate units for a first-order rate constant are

Exam 14: Chemical Kinetics

The graphs below all refer to the same reaction. What is the order of this reaction?

The rate constant for the first-order decomposition of C4H8 at 500°C is 9.2 * 10-3 s-1. How long will it take for 10.0% of a 0.100 M sample of C4H8 to decompose at 500°C?

The Arrhenius equation is k = Ae-Ea/RT. The slope of a plot of ln k vs. 1/T is equal to

In the reaction, 2N2O →\rarr→ 2N2 + O2, oxygen and nitrogen gases are formed at the same rate (mol/L·s).

For the following reaction, Δ\DeltaΔ P(C6H14) / Δ\DeltaΔ t was found to be -6.2 * 10-3 atm/s. C6H14(g) →\rarr→ C6H6(g) + 4H2(g) Determine Δ\DeltaΔ P(H2) / Δ\DeltaΔ t for this reaction at the same time.

For the chemical reaction system described by the diagram below, which statement is true? If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is Ea for the reverse reaction?

The isomerization of cyclopropane to propene follows first-order kinetics. At 700 K, the rate constant for this reaction is 6.2 * 10-4 min-1. How many minutes are required for 10.0% of a sample of cyclopropane to isomerize to propene?

The reaction 2NO2(g) →\rarr→ 2NO(g) + O2(g) is suspected to be second order in NO2. Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,

At a certain temperature, the data below were collected for the reaction below. 2ICl + H2 →\rarr→ I2 + 2HCl. Determine the rate constant for the reaction.

The thermal decomposition of acetaldehyde, CH3CHO →\rarr→ CH4 + CO, is a second-order reaction. The following data were obtained at 518°C. Based on the data given, what is the half-life for the disappearance of acetaldehyde?

A first-order reaction has a rate constant of 7.5 * 10-3 /s. The time required for the reaction to be 60% complete is

A rate constant will have the units mol · L-1 · s-1 when the reaction is overall

For the chemical reaction system described by the diagram below, which statement is true?

A rate constant with the units L2 · mol-2 · s-1 is consistent with a

What is the slope of an Arrhenius plot for the following reaction? 2NOCl →\rarr→ 2NO + Cl2

Appropriate units for a first-order rate constant are

The rate constant for the first-order decomposition of C₄H₈ at 500°C is 9.2 * 10^-3 s^-1. How long will it take for 10.0% of a 0.100 M sample of C₄H₈ to decompose at 500°C?

The Arrhenius equation is k = Ae^-Ea/RT. The slope of a plot of ln k vs. 1/T is equal to

In the reaction, 2N₂O $\rarr$ 2N₂ + O₂, oxygen and nitrogen gases are formed at the same rate (mol/L·s).

For the following reaction, $\Delta$ P(C₆H₁₄) / $\Delta$ t was found to be -6.2 * 10^-3 atm/s. C₆H₁₄(g) $\rarr$ C₆H₆(g) + 4H₂(g) Determine $\Delta$ P(H₂) / $\Delta$ t for this reaction at the same time.

For the chemical reaction system described by the diagram below, which statement is true? If the E_a for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is E_a for the reverse reaction?

The isomerization of cyclopropane to propene follows first-order kinetics. At 700 K, the rate constant for this reaction is 6.2 * 10^-4min^-1. How many minutes are required for 10.0% of a sample of cyclopropane to isomerize to propene?

The reaction 2NO₂(g) $\rarr$ 2NO(g) + O₂(g) is suspected to be second order in NO₂. Which of the following kinetic plots would be the most useful to confirm whether or not the reaction is second order?

A first-order reaction has a rate constant of 7.5 * 10^-3/s. The time required for the reaction to be 60% complete is

A rate constant will have the units mol · L^-1 · s^-1 when the reaction is overall

A rate constant with the units L² · mol^-2 · s^-1 is consistent with a