Question 1

Which of the following best describes the main focus of chemical kinetics?

Accepted Answer

The study of how rates of chemical reactions are affected by various factors.

Question 2

Ectothermic animals, such as lizards, become lethargic in cold weather because:

Accepted Answer

Their body temperature drops, slowing down chemical reactions.

Question 3

Which of the following is the correct general form of a rate law for the reaction $A + B ightarrow 	ext{products}$?

Accepted Answer

$	ext{Rate} = k[A]^n[B]^m$

Question 4

For the reaction $2NO_2(g) ightarrow 2NO(g) + O_2(g)$, if the rate law is $	ext{Rate} = k[NO_2]^2$, what is the order of the reaction?

Accepted Answer

Second order

Question 5

If doubling the concentration of reactant A quadruples the rate of the reaction, what is the order of the reaction with respect to A?

Accepted Answer

Second order

Question 6

Which experimental method is commonly used to measure the concentration of colored reactants or products over time in a reaction?

Accepted Answer

Spectrophotometry

Question 7

Given the reaction $BrO_3^-(aq) + 5Br^-(aq) + 6H^+(aq) ightarrow 3Br_2(l) + 3H_2O(l)$, if the rate law is $	ext{Rate} = k[BrO_3^-][Br^-][H^+]^2$, what is the overall order of the reaction?

Accepted Answer

Fourth order

Question 8

Which of the following statements about the rate constant $k$ is TRUE?

Accepted Answer

It depends only on temperature and the presence of a catalyst.

Question 9

For a first-order reaction, which of the following plots will yield a straight line?

Accepted Answer

$\ln[A]$ vs. time

Question 10

The half-life $t_{1/2}$ for a first-order reaction is given by which equation?

Accepted Answer

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

Question 11

The Arrhenius equation relates the rate constant $k$ to temperature $T$ and activation energy $E_a$. Which is the correct form of the Arrhenius equation?

Accepted Answer

$k = Ae^{-E_a/RT}$

Question 12

In a reaction mechanism, what is the rate-determining step?

Accepted Answer

The slowest step with the highest activation energy.

Question 13

Which of the following best describes a catalyst in a chemical reaction?

Accepted Answer

A substance that provides an alternative pathway with lower activation energy and is regenerated at the end.

Question 14

For a zero-order reaction, which of the following is true about the rate?

Accepted Answer

It is constant and independent of reactant concentration.

Question 15

Which factor does NOT affect the rate constant $k$ in the Arrhenius equation?

Accepted Answer

Concentration of reactants

Question 16

In the context of reaction mechanisms, what is an intermediate?

Accepted Answer

A product that is formed and consumed during the mechanism but does not appear in the overall reaction.

Question 17

If the rate law for a reaction is $	ext{Rate} = k[A]^0$, what will happen to the rate if the concentration of A is doubled?

Accepted Answer

The rate will remain unchanged.

Question 18

Which plot would you use to determine the activation energy $E_a$ from experimental data using the Arrhenius equation?

Accepted Answer

$\ln(k)$ vs. $1/T$

Question 19

Enzymes are biological catalysts. Which statement best describes how enzymes increase reaction rates?

Accepted Answer

By lowering the activation energy through specific orientation of substrates.

Question 20

A reaction is found to be first order in [A] and second order in [B]. If the concentration of A is doubled and B is tripled, by what factor does the rate increase?

Accepted Answer

12

Chemical Kinetics: Study Notes

Study Guide - Practice Questions

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