Q: A student measures the rate of disappearance of ozone in the reaction $$2O_3(g) \rightarrow 3O_2(g) as$$ $$1.00 \times 10$$^{-5}$$ atm/s. What is the rate of appearance of O_2$?

$$1.50 \times 10$$^{-5}$$ atm/s

Q: Which of the following is the correct rate law for the reaction $$BrO_3^-(aq) + 5Br^-(aq) + 6H^+(aq$$) \rightarrow $$Br_2(aq) + 3H_2O(l$$)$$ if it is zero order in $$BrO_3$$^-$$, second order in $$Br^-$$, and first order in $$H^+$$?

$$\text{rate} = k[Br^-]^2[H^+]$$

Question 1

Which of the following statements best describes the difference between chemical kinetics and chemical thermodynamics?

Accepted Answer

Thermodynamics studies the energy changes and feasibility of a reaction, while kinetics studies the speed and mechanism of the reaction.

Question 2

A reaction has a high activation energy. What can you infer about the rate of this reaction under standard conditions?

Accepted Answer

The reaction rate will be slow unless a catalyst is present or temperature is increased.

Question 3

For the reaction $$2NO_2(g) ightarrow 2NO(g) + O_2$(g)$$, the rate law is experimentally determined to be $$	ext{rate} = k[NO_2$]^2. $$What is the order of the reaction?

Accepted Answer

Second order

Question 4

Which of the following will NOT increase the rate of a chemical reaction?

Accepted Answer

Decreasing the surface area of a solid reactant

Question 5

Consider the reaction $$aA + bB ightarrow cC + dD. $$The rate expression is $$	ext{rate} = k[A]^m[B]^n. $$Which statement is TRUE about the exponents $$m$$ and $$n$$?

Accepted Answer

They must be determined experimentally and may differ from $$a$$ and $$b.$$

Question 6

A student measures the rate of disappearance of ozone in the reaction $$2O_3(g) ightarrow 3O_2(g) as$$ $$1.00 	imes 10$$^{-5}$$ atm/s. What is the rate of appearance of O_2$?

Accepted Answer

$$1.50 	imes 10$$^{-5}$$ atm/s

Question 7

Which of the following is the correct rate law for the reaction $$BrO_3^-(aq) + 5Br^-(aq) + 6H^+(aq$$) \rightarrow $$Br_2(aq) + 3H_2O(l$$)$$ if it is zero order in $$BrO_3$$^-$$, second order in $$Br^-$$, and first order in $$H^+$$?

Accepted Answer

$$	ext{rate} = k[Br^-]^2[H^+]$$

Question 8

The decomposition of $$N_2O is $$first order in $$N_2O. If$$ $$k = 0.105\ s$$^{-1}$$ and $$[N_2O] = 0.20\ M$$, what is the reaction rate?

Accepted Answer

$$0.021\ M/s$$

Question 9

Which graph would be linear for a first order reaction when plotting concentration data over time?

Accepted Answer

$$\ln[A] vs$$. $$t$$

Question 10

For a first order reaction, what is the formula for the half-life ($$t_{1/2}$$)?

Accepted Answer

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

Question 11

A second order reaction has a rate constant $$k = 0.0796\ M$$^{-1}$$s^{-1}$$ and initial concentration $$[NO] = 0.0125\ M. $$What is $$[NO]$$ after $$5$ minutes?

Accepted Answer

$$0.0112\ M$$

Question 12

Which of the following best explains why reaction rates typically decrease as a reaction proceeds?

Accepted Answer

The concentration of reactants decreases, leading to fewer effective collisions.

Question 13

If the rate law for a reaction is $$	ext{rate} = k[A]^2$$, what will happen to the rate if $$[A] is $$doubled?

Accepted Answer

The rate will quadruple.

Question 14

Which of the following is TRUE about the rate constant $$k in a $$rate law?

Accepted Answer

Its units depend on the overall order of the reaction.

Question 15

A glow stick glows brighter in hot water than in cold water. Which factor is responsible for this observation?

Accepted Answer

Increased temperature increases reaction rate

Question 16

Which statement about catalysts is correct?

Accepted Answer

Catalysts provide an alternative pathway with lower activation energy.

Question 17

For a zero order reaction, which integrated rate law correctly relates concentration and time?

Accepted Answer

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

Question 18

A reaction is performed at 25°C and is 46% complete after 68 minutes. What is the rate constant $$k (in$$ $$min^{-1}) $$for this first order reaction?

Accepted Answer

$$0.011\ $$min^{-1}$$

Question 19

Which of the following is a correct statement about the equilibrium constant $$K$$?

Accepted Answer

It is the ratio of product concentrations to reactant concentrations at equilibrium.

Core Questions and Concepts in General Chemistry II (CHM 116)

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