Which changes produce the greatest increase in the percentage conversion of methane?

CH₄(g) + H₂O (g) $\rightleftharpoons$ CO (g) + 3H₂(g)

C

$\frac{1}{2}$Cl₂(g) + $\frac{1}{2}{\text{I}}_2$(g) $\rightleftharpoons$ $\text{I}$Cl (g)    K_c = 454

What is the K_c value for the reaction below?

2 $\text{I}$Cl (g) $\rightleftharpoons$ Cl₂(g) + ${\text{I}}_{\text{2}}$(g)

A.  $2\times 454$

B.  $\frac{1}{2\times 454}$

C.  ${454}^2$

D.  $\frac{1}{{454}^2}$

D

Question 18 was identified as being mathematically challenging. However, as all answers were shown as calculations rather than as final answers, this does not seem a reasonable complaint.

What will happen if the pressure is increased in the following reaction mixture at equilibrium?

CO₂ (g) + H₂O (l) $\rightleftharpoons$ H⁺ (aq) + HCO₃⁻ (aq)

A. The equilibrium will shift to the right and pH will decrease.

B. The equilibrium will shift to the right and pH will increase.

C. The equilibrium will shift to the left and pH will increase.

D. The equilibrium will shift to the left and pH will decrease.

A

What effect does a catalyst have on the position of equilibrium and the value of the equilibrium constant, K_c, for an exothermic reaction?

C

Consider the equilibrium between N₂O₄(g) and NO₂(g).

N₂O₄(g) $\rightleftharpoons$ 2NO₂(g)          ΔH = +58 kJ$$mol⁻¹

Which changes shift the position of equilibrium to the right?

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

A

The equilibrium 2H₂ (g) + N₂(g) $\rightleftharpoons$ N₂H₄(g) has an equilibrium constant, K, at 150 °C. 

What is the equilibrium constant at 150 °C, for the reverse reaction?

N₂H₄(g) $\rightleftharpoons$ 2H₂ (g) + N₂(g)

A.  K

B.  K⁻¹

C.  −K

D.  2K

B

Consider the reaction:

2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g)

The values of K_c at different temperatures are:

Which statement is correct at higher temperature?

A.   The forward reaction is favoured.

B.   The reverse reaction is favoured.

C.   The rate of the reverse reaction is greater than the rate of the forward reaction.

D.   The concentration of both reactants and products increase.

A

What happens when the temperature of the following equilibrium system is increased? 

CO(g) + 2H₂(g)  CH₃OH(g)         ΔH^θ = -91kJ

A

Which factor does not affect the position of equilibrium in this reaction?

2NO₂(g) $\rightleftharpoons$ N₂O₄(g)     ΔH = −58 kJ mol⁻¹

A.     Change in volume of the container

B.     Change in temperature

C.     Addition of a catalyst

D.     Change in pressure

C

What is the equilibrium constant expression, K_c, for the following reaction?

2NH₃(g) + 2O₂(g) $\rightleftharpoons$ N₂O(g) + 3H₂O(g)

A.     $\frac{3\left[{\text{H}}_2\text{O}\right]\left[{\text{N}}_2\text{O}\right]}{2\left[\text{N}{\text{H}}_3\right]2\left[{\text{O}}_2\right]}$

B.     $\frac{{\left[\text{N}{\text{H}}_3\right]}^2{\left[{\text{O}}_2\right]}^2}{\left[{\text{N}}_2\text{O}\right]{\left[{\text{H}}_2\text{O}\right]}^3}$

C.     $\frac{2\left[\text{N}{\text{H}}_3\right]2\left[{\text{O}}_2\right]}{3\left[{\text{H}}_2\text{O}\right]\left[{\text{N}}_2\text{O}\right]}$

D.     $\frac{\left[{\text{N}}_2\text{O}\right]{\left[{\text{H}}_2\text{O}\right]}^3}{{\left[\text{N}{\text{H}}_3\right]}^2{\left[{\text{O}}_2\right]}^2}$

D

What is correct when temperature increases in this reaction at equilibrium?

$2\mathrm{NOCl} \left(\mathrm{g}\right)\rightleftharpoons 2\mathrm{NO} \left(\mathrm{g}\right)+{\mathrm{Cl}}_2 \left(\mathrm{g}\right)$    $∆H^{⦵}=+75.5 \mathrm{kJ}$

D

A good majority of candidates understood how position of equilibrium and rate constant of an endothermic reaction are affected by temperature increase.

Which species are acids in the equilibrium below?

CH₃NH₂ + H₂O $\rightleftharpoons$ CH₃NH₃⁺ + OH^–

A.  CH₃NH₂ and H₂O

B.  H₂O and CH₃NH₃⁺

C.  H₂O and OH^–

D.  CH₃NH₂ and CH₃NH₃⁺

B

The equilibrium constant for N₂(g) + 3H₂(g) $\rightleftharpoons$ 2NH₃(g) is K.

What is the equilibrium constant for this equation?

2N₂(g) + 6H₂(g) $\rightleftharpoons$ 4NH₃(g)

A.     K

B.     2K

C.     K²

D.     2K²

C