Question 1

A student is analyzing the decomposition of hydrogen peroxide ($\mathrm{H_2O_2}$) and collects concentration data over time. The student plots $[\mathrm{H_2O_2}]$ vs. time and $\ln[\mathrm{H_2O_2}]$ vs. time. The $\ln[\mathrm{H_2O_2}]$ vs. time plot is linear. What is the order of the reaction with respect to $\mathrm{H_2O_2}$?

Accepted Answer

First order

Question 2

Given the linear equation from the $\ln[\mathrm{H_2O_2}]$ vs. time plot: $y = -0.0358x + 0.1058$, what is the rate constant $k$ for the reaction?

Accepted Answer

$k = 0.0358\ \mathrm{min}^{-1}$

Question 3

For a first-order reaction, which integrated rate law equation correctly relates concentration and time?

Accepted Answer

$\ln[A]_t = -kt + \ln[A]_0$

Question 4

A reaction has a rate law: $	ext{rate} = k[A][B]^2$. If the concentration of $B$ is doubled while $A$ remains constant, by what factor does the rate increase?

Accepted Answer

4

Question 5

Which of the following is the correct expression for the half-life of a first-order reaction?

Accepted Answer

$t_{1/2} = \frac{0.693}{k}$

Question 6

A student observes that the rate of a reaction doubles when the temperature is increased by 10°C. Which concept best explains this observation?

Accepted Answer

Arrhenius Equation

Question 7

If the rate law for a reaction is $	ext{rate} = k[A]^2$, what are the units of the rate constant $k$?

Accepted Answer

$\mathrm{L\ mol^{-1}\ s^{-1}}$

Question 8

A reaction is monitored and the following data is collected: $[A]$ decreases from 0.50 M to 0.25 M in 20 minutes. If the reaction is first order, what is the rate constant $k$?

Accepted Answer

$k = 0.0347\ \mathrm{min}^{-1}$

Question 9

Which graph would be linear for a second-order reaction with respect to $A$?

Accepted Answer

$\frac{1}{[A]}$ vs. time

Question 10

A reaction has the following rate law: $	ext{rate} = k[A]^0[B]^1$. Which statement is true about the effect of changing $[A]$?

Accepted Answer

Changing $[A]$ has no effect on the rate

Question 11

In a medical scenario, a drug is eliminated from the bloodstream by a first-order process. If the initial concentration is 0.80 mg/L and the half-life is 15 hours, what will the concentration be after 30 hours?

Accepted Answer

0.20 mg/L

Question 12

Which of the following best describes the effect of a catalyst on a chemical reaction?

Accepted Answer

It lowers the activation energy

Question 13

A student is given the following data for a reaction: $[A]$ (M): 0.10, 0.20, 0.40; Initial Rate ($\mathrm{mol\ L^{-1}\ s^{-1}}$): 0.05, 0.10, 0.20. What is the order of the reaction with respect to $A$?

Accepted Answer

First order

Question 14

For a reaction with the rate law $	ext{rate} = k[A][B]$, what is the overall order of the reaction?

Accepted Answer

Second order

Question 15

Which of the following statements about reaction mechanisms is correct?

Accepted Answer

The slowest step determines the overall rate

Question 16

A reaction is zero order in $A$. If $[A]$ starts at 0.50 M and decreases to 0.20 M in 6 minutes, what is the rate constant $k$?

Accepted Answer

$k = 0.05\ \mathrm{M\ min^{-1}}$

Question 17

Which of the following is NOT a valid method for determining reaction order experimentally?

Accepted Answer

Assuming the order from the balanced chemical equation

Question 18

A reaction has a rate law $	ext{rate} = k[A]^2[B]$. If $[A]$ is halved and $[B]$ is doubled, how does the rate change?

Accepted Answer

It is halved

Question 19

Which of the following best describes the relationship between activation energy and reaction rate?

Accepted Answer

Lower activation energy leads to a faster reaction

Chemical Kinetics: Rate Laws, Data Analysis, and Reaction Mechanisms

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