Question

The reaction of coke and steam at high temperatures produces H2 and CO gases. At 1000 Kelvin, K = 0.75. H2O (g) + C (s) ⇌ H2(g) + CO (g) 1 mol of gas (reactant side) 2 mol gas (product side). If you have steam and carbon in an isolated container at 1000 Kelvin at equilibrium. Which of the following would increase the amount of H2 in the container?

a.) Adding an atmosphere of CO(g).
b.) Adding an atmosphere of N2(g).
c.) Decreasing the volume of the container.
d.) Increasing the volume of the container.

Answer 1

To increase the amount of H2 in a container at equilibrium at 1000 Kelvin for the reaction C(s) + H2O(g) ⇌ H2(g) + CO(g), increasing the volume of the container would be the correct choice.

Step-by-step explanation:

When considering the reaction C(s) + H₂O(g) ⇌ H₂(g) + CO(g) at an equilibrium with K = 0.75 at 1000 Kelvin, adding an atmosphere of CO(g) would shift the reaction to the left, decreasing the amount of H2. Adding N2(g) would have no effect as it is an inert gas and does not participate in the reaction. Decreasing the volume of the container would increase the pressure, shifting the equilibrium to the side with fewer moles of gas, which is the reactant side, thus decreasing the amount of H2. Increasing the volume of the container would decrease pressure, shifting the reaction to the side with the larger number of moles of gas, which is the product side, thereby increasing the amount of H2.

Answer 2

To increase the hydrogen gas (H2) concentration, we need to shift the equilibrium of the reaction to the right. The correct answer is d.) Increasing the volume of the container, which will lower the pressure and shift the equilibrium to the side with more gas moles, thus increasing H2 amount.

Step-by-step explanation:

The reaction in question is the formation of water gas through the reaction of steam with carbon. We are given the equilibrium constant (K) for the reaction at 1000 Kelvin and asked to determine which option would increase the concentration of hydrogen gas (H2) in the container.

The equilibrium constant expression for the reaction C(s) + H2O(g) ⇌ CO(g) + H2(g) is K = [H2][CO]/[H2O], where concentrations of solids are omitted. To increase the amount of H2, we need to shift the equilibrium to the right.

• a.) Adding an atmosphere of CO(g): This will shift the equilibrium to the left per Le Chatelier's principle, decreasing the amount of H2.
• b.) Adding an atmosphere of N2(g): This will have no effect on the equilibrium because N2 does not participate in the reaction.
• c.) Decreasing the volume of the container: This will increase the pressure, shifting the equilibrium to the side with fewer moles of gas, which is the left, thus reducing the amount of H2.
• d.) Increasing the volume of the container: This will decrease pressure, shifting the equilibrium to the side with more moles of gas, which is the right, increasing the amount of H2.

Therefore, the correct answer is d.) Increasing the volume of the container, as it will shift the equilibrium toward the production of more H2.