10-minute Quiz : Chapter 41

Consider the equilibrium mixture with a purple colour shown in the diagram. What would be observed when water is added to the mixture?

• A. The mixture remains purple as water is colourless.
• B. The mixture becomes less purple as the concentration of all coloured species decreases.
• C. The mixture turns blue as the system produces more CoCl₄²⁻(aq).
• D. The mixture turns pink as the system produces more Co(H₂O)₆²⁺(aq).

Which of the following reactions would be favoured by increasing the pressure at constant temperature?

• A. N₂(g) + O₂(g) ⇌ 2NO(g)
• B. 2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
• C. PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)
• D. H₂(g) + I₂(g) ⇌ 2HI(g)

Direction: Questions 3 and 4 refer to the reversible reaction shown in the diagram.

At a given moment, a fixed-volume closed vessel maintained at 445°C contains 2.0 M of HI(g), 0.50 M of H₂(g) and 0.10 M of I₂(g). What is the reaction quotient of the reaction at that moment?

• A. 0.0125
• B. 0.025
• C. 2
• D. 4

Direction: Questions 3 and 4 refer to the reversible reaction shown in the diagram.

Which of the statements correctly describes the shift in the equilibrium position of the reaction at that moment?

• A
• B
• C
• D

The dissociation of dinitrogen tetraoxide into nitrogen dioxide can be represented by the following equation:

N₂O₄(g) ⇌ 2NO₂(g)　　ΔH = +58 kJ mol⁻¹

Which of the following statements correctly describes and explains the volume change of the gaseous mixture mentioned above when its temperature is increased at a constant pressure?

• A. The volume will decrease. This is because the equilibrium position shifts to the left, leading to the consumption of some gas.
• B. The volume will increase. This is because the equilibrium position shifts to the right, leading to the formation of some gas. Moreover, gas expands because of the heat.
• C. The volume will remain more or less the same because the thermal expansion of gas can counteract the gas consumption caused by the shift of the equilibrium position to the left.
• D. The volume will decrease because the thermal expansion of gas cannot completely counteract the gas consumption caused by the shift of the equilibrium position to the left.

Consider the following equilibrium system:

C₂H₅OH(l) + Br⁻(aq) ⇌ C₂H₅Br(l) + OH⁻(aq)

Which of the following changes can cause the equilibrium position of the system to shift to the right?

• A. Exposing the system to light
• B. Adding an alkali to the system
• C. Adding an acid to the system
• D. Adding C₂H₅Br(l) to the system

Consider the following equilibrium system:

2ICl(g) ⇌ I₂(g) + Cl₂(g)

Which of the following changes could increase the yield of Cl₂(g)?

(1) Removing some I₂(g) from the system

(2) Adding some ICl(g) to the system

(3) Removing some Cl₂(g) from the system

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Methanol can be synthesized industrially by converting a gaseous mixture of carbon monoxide and hydrogen in the presence of a copper-based catalyst at 250°C and 50–100 atm.

CO(g) + 2H₂(g) ⇌ CH₃OH(g)　　ΔH = −90 kJ mol⁻¹

Which of the following statements concerning the above conversion is correct?

• A. Using a catalyst in the conversion can increase the yield of methanol.
• B. Operating the conversion at a lower pressure can increase the rate of formation of methanol.
• C. Operating the conversion at a lower temperature can increase the yield of methanol.
• D. Operating the conversion at a lower temperature can increase the rate of formation of methanol.

Consider the following gaseous chemical equilibrium that carried out in a closed container under certain conditions:

X₂(g) + Y₂(g) ⇌ Z₂(g)　　ΔH < 0

Which of the following changes can increase the equilibrium number of moles of X₂(g)?

(1) Increasing the temperature of the system at a constant pressure

(2) Decreasing the pressure of the system at a constant temperature

(3) Removing some Z₂(g) from the system

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)