Q: For the reaction $2\text{SO}_2(g) + \text{O}_2(g) \rightarrow 2\text{SO}_3(g)$, what is the correct relationship between the rates of disappearance of SO$_2$ and O$_2$ and the rate of appearance of SO$_3$?

$\text{Rate}_{\text{SO}_2} = 2 \times \text{Rate}_{\text{O}_2}$

Question 1

Which of the following best describes the effect of increasing the concentration of reactants on the rate of a chemical reaction, according to collision theory?

Accepted Answer

It increases the number of collisions, thus speeding up the reaction.

Question 2

For the reaction $2	ext{SO}_2(g) + 	ext{O}_2(g) ightarrow 2	ext{SO}_3(g)$, what is the correct relationship between the rates of disappearance of SO$_2$ and O$_2$ and the rate of appearance of SO$_3$?

Accepted Answer

$	ext{Rate}_{	ext{SO}_2} = 2 	imes 	ext{Rate}_{	ext{O}_2}$

Question 3

A reaction is found to be first order in reactant A and second order in reactant B. Which of the following is the correct rate law for this reaction?

Accepted Answer

$	ext{Rate} = k[A][B]^2$

Question 4

Which graphical method would you use to determine if a reaction is first order with respect to a reactant?

Accepted Answer

Plot $\ln[R]$ vs. time and look for a straight line.

Question 5

The half-life for a first-order reaction is given by which equation?

Accepted Answer

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

Question 6

Which of the following statements about catalysts is TRUE?

Accepted Answer

A catalyst provides a different pathway with lower activation energy.

Question 7

Given the Arrhenius equation $k = Ae^{-E_a/(RT)}$, what happens to the rate constant $k$ as temperature increases?

Accepted Answer

The rate constant $k$ increases.

Question 8

For the equilibrium reaction $	ext{N}_2(g) + 3	ext{H}_2(g) ightleftharpoons 2	ext{NH}_3(g)$, if the equilibrium constant $K_c = 3.5 	imes 10^8$, what does this indicate about the equilibrium position?

Accepted Answer

The reaction is product-favored at equilibrium.

Question 9

If the reaction quotient $Q$ for a system is less than the equilibrium constant $K$, which direction will the reaction proceed?

Accepted Answer

The reaction will proceed in the forward direction.

Question 10

Which of the following changes will NOT affect the value of the equilibrium constant $K$ for a reaction?

Accepted Answer

Adding a catalyst.

Question 11

According to Le Chatelier’s Principle, what happens to the equilibrium position of a gas-phase reaction if the volume of the container is decreased?

Accepted Answer

The equilibrium shifts toward the side with fewer molecules of gas.

Question 12

Which of the following is a correct expression for the equilibrium constant $K_c$ for the reaction $	ext{S}(s) + 	ext{O}_2(g) ightleftharpoons 	ext{SO}_2(g)$?

Accepted Answer

$K_c = \frac{[SO_2]}{[O_2]}$

Question 13

Which of the following is a Brønsted–Lowry acid?

Accepted Answer

A substance that donates a proton (H+).

Question 14

What is the pH of a 0.1 M solution of HCl?

Accepted Answer

pH = 1.0

Question 15

Which of the following salts will produce a basic solution when dissolved in water?

Accepted Answer

NaCH3COO

Question 16

For a weak acid HA, the acid dissociation constant $K_a$ is given by which expression?

Accepted Answer

$K_a = \frac{[H_3O^+][A^-]}{[HA]}$

Question 17

If the $K_a$ for acetic acid is $1.8 	imes 10^{-5}$ at 25°C, what is the $K_b$ for its conjugate base?

Accepted Answer

$K_b = \frac{K_w}{K_a}$

Question 18

Which of the following statements about polyprotic acids is TRUE?

Accepted Answer

Each successive ionization constant ($K_a$) is smaller than the previous one.

Question 19

For the reaction $	ext{H}_2	ext{CO}_3 (aq) + 	ext{H}_2	ext{O} (l) ightleftharpoons 	ext{H}_3	ext{O}^+ (aq) + 	ext{HCO}_3^- (aq)$, if the initial concentration of $	ext{H}_2	ext{CO}_3$ is 0.10 M and $K_a = 4.2 	imes 10^{-7}$, what is the approximate equilibrium concentration of $	ext{H}_3	ext{O}^+$?

Accepted Answer

2.0 	imes 10^{-4} M

Unit 2: Chemical Kinetics, Equilibrium, and Acids/Bases – Mini-Textbook Study Guide

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