Question 1

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

Accepted Answer

A catalyst lowers the activation energy, allowing the reaction to proceed faster.

Question 2

Given the following equilibrium: $$\mathrm{N_2O_4(g) \rightleftharpoons 2NO_2(g)}$$, which change will shift the equilibrium toward the formation of $$\mathrm{NO_2$}$$?

Accepted Answer

Increasing the temperature

Question 3

A student dissolves $$0.10$$ mol of $$\mathrm{NaCl} in$$ $$1.0 L of $$water. Which of the following best describes the resulting solution?

Accepted Answer

It is an unsaturated solution.

Question 4

Which of the following compounds has the highest solubility in water at $$25^\circC $$according to the provided solubility table?

Accepted Answer

NaNO$$_3$$

Question 5

If $$35.7 g of$$ $$\mathrm{NaCl} is $$dissolved in $$100 g of $$water at $$25^\circC$$, what type of solution is formed?

Accepted Answer

Saturated

Question 6

Which of the following best explains why $$\mathrm{$$NaNO_3$$} is $$more soluble in water than $$\mathrm{NaCl} at$$ $$25^\circC$$?

Accepted Answer

The lattice energy of $$\mathrm{$$NaNO_3$$} is $$lower than that of $$\mathrm{NaCl}.$$

Question 7

A solution contains $$50 g of$$ $$\mathrm{$$KNO_3$$} in$$ $$100 g of $$water at $$25^\circC. $$According to the solubility table, is this solution saturated, unsaturated, or supersaturated?

Accepted Answer

Unsaturated

Question 8

Which of the following is the correct expression for the equilibrium constant $$K_c$$ for the reaction $$\mathrm{N_2O_4(g) \rightleftharpoons 2NO_2(g)}$$?

Accepted Answer

$$K_c = \dfrac{[NO_2$]^2}{[N_2O_4]}$$

Question 9

If the equilibrium concentration of $$\mathrm{NO_2$} is$$ $$0.20 M $$and $$\mathrm{N_2O_4} is$$ $$0.10 M$$, what is the value of $$K_c$$ for the reaction $$\mathrm{N_2O_4(g) \rightleftharpoons 2NO_2(g)}$$?

Accepted Answer

$$K_c = 0.40$$

Question 10

A chemist wants to increase the rate of a reaction without affecting the equilibrium position. Which method should they use?

Accepted Answer

Add a catalyst

Question 11

Which of the following best describes a saturated solution?

Accepted Answer

A solution in which the rate of dissolution equals the rate of precipitation.

Question 12

If $$36 g of$$ $$\mathrm{KCl} is $$dissolved in $$100 g of $$water at $$25^\circC$$, what is the status of the solution according to the solubility table?

Accepted Answer

Saturated

Question 13

Which of the following changes will NOT affect the position of equilibrium for a chemical reaction?

Accepted Answer

Adding a catalyst

Question 14

A solution at $$25^\circC $$contains $$40 g of$$ $$\mathrm{$$NaNO_3$$} in$$ $$100 g of $$water. What is the best description of this solution?

Accepted Answer

Supersaturated

Question 15

Which of the following statements is true regarding the effect of temperature on the solubility of most solid salts in water?

Accepted Answer

Solubility increases as temperature increases.

Question 16

A student prepares a solution by dissolving $$30 g of$$ $$\mathrm{KCl} in$$ $$100 g of $$water at $$25^\circC. $$According to the solubility table, what type of solution is this?

Accepted Answer

Unsaturated

Question 17

Which of the following is a correct statement about dynamic equilibrium in a chemical system?

Accepted Answer

The rates of the forward and reverse reactions are equal.

Question 18

If the equilibrium constant $$K_c$$ for a reaction is much greater than $$1$$, what does this indicate about the reaction at equilibrium?

Accepted Answer

Products are favored at equilibrium.

Question 19

A solution contains $$40 g of$$ $$\mathrm{NaCl} in$$ $$100 g of $$water at $$25^\circC. $$According to the solubility table, what is the status of this solution?

Accepted Answer

Supersaturated

Question 20

Which of the following best describes the effect of increasing pressure on the equilibrium of a reaction involving gases?

Accepted Answer

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

Study Notes: Atomic Structure, Isotopes, and Atomic Mass Calculations

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