KINETICS/EQUILIBRIUM/HEAT

Base your answer to the following question on the table below, which represents the production of 50 milliliters of CO₂ in the reaction of HCl with NaHCO₃. Five trials were performed under different conditions as shown. (The same mass of NaHCO₃ was used in each trial.) Which two trials could be used to measure the effect of surface area?

• trials A and B

• trials A and C

• trials A and D

• trials B and D

Base your answer to the following question on the potential energy diagram below, which represents the reaction: A + B → C + energy

Which number will change with the addition of a catalyst to the system?

• 1

• 2

• 3

• 4

Entropy is a measure of

• the disorder of a system

• accuracy

• precision

• the attraction of a nucleus for an electron

Given the equation representing a reaction at equilibrium: N₂(g) + 3H₂(g) ↔ 2NH₃(g). What occurs when the concentration of H₂(g) is increased?

• A) The equilibrium shifts to the left, and the concentration of N₂(g) decreases.

• B) The equilibrium shifts to the left, and the concentration of N₂(g) increases.

• C) The equilibrium shifts to the right, and the concentration of N₂ (g) decreases.

• D) The equilibrium shifts to the right, and the concentration of N₂(g) increases.

At 101.3 kPa and 298 K, what is the total amount of heat released when one mole of aluminum oxide, Al₂O₃(s), is formed from its elements?

• A) 393.5 kJ

• B) 837.8 kJ

• C) 1676 kJ

• D) 3351 kJ

Systems in nature tend to undergo changes toward:

• A) lower energy and lower entropy

• B) lower energy and higher entropy

• C) higher energy and lower entropy

• D) higher energy and higher entropy

Given the reaction at equilibrium: 2 SO₂(g) + O₂(g) ↔ 2 SO₃(g) + heat. Which change will shift the equilibrium to the right?

• A) increasing the pressure

• B) decreasing the amount of SO2(g)

• C) decreasing the amount of O2(g)

• D) increasing the temperature

Given the equation representing a system at equilibrium in a sealed, rigid container: 2HI(g) ↔ H₂(g) + I₂(g) + energy. Increasing the temperature of the system causes the concentration of:

• A) H2 to remain constant

• B) HI to remain constant

• C) HI to increase

• D) H2 to increase

Which mathematical expression represents the heat of reaction for a chemical change?

• A) (PE of the products) + (PE of the reactants)

• B) (PE of the products) + (PE of the reactants)

• C) (PE of the products) × (PE of the reactants)

• D) (PE of the products) - (PE of the reactants)

Given the balanced equation representing a reaction: CH₄(g) + 2O₂(g) → 2H₂O(g) + CO₂(g) + heat. Which statement is true about energy in this reaction?

• A) The reaction is endothermic because it absorbs heat.

• B) The reaction is exothermic because it absorbs heat.

• C) The reaction is exothermic because it releases heat.

• D) The reaction is endothermic because it releases heat.