Question

Water gas, a mixture of H₂ and CO, is an important industrial fuel produced by the reaction of steam with red hot coke, essentially pure carbon.

(a) Write the expression for the equilibrium constant for the reversible reaction

C(s) + H₂O(g) ⇌ CO(g) + H₂(g) ΔΗ - 131.30 kJ

(b) What will happen to the concentration of each reactant and product at equilibrium if more C is added?
(c) What will happen to the concentration of each reactant and product at equilibrium if H2O is removed?
(d) What will happen to the concentration of each reactant and product at equilibrium if CO is added?
(e) What will happen to the concentration of each reactant and product at equilibrium if the temperature of the system is increased?

Answer 1

The equilibrium constant expression for the reaction is K = [CO][H₂] / [C][H₂O]. If more C is added, the concentrations of CO and H₂ will increase, while the concentrations of C and H₂O will decrease. If H₂O is removed, the equilibrium will shift to the left. If CO is added, the equilibrium will shift to the left. If the temperature is increased, the equilibrium will shift in the endothermic direction.

Step-by-step explanation:

(a) The expression for the equilibrium constant for the reversible reaction C(s) + H₂O(g) ⇌ CO(g) + H₂(g) is K = [CO][H₂] / [C][H₂O].

(b) If more C is added, according to Le Chatelier's principle, the equilibrium will shift to the right to relieve the stress. This means that the concentrations of CO and H₂ will increase, while the concentrations of C and H₂O will decrease.

(c) If H₂O is removed, the equilibrium will shift to the left to replace the lost reactant. This means that the concentrations of CO and H₂ will decrease, while the concentrations of C and H₂O will increase.

(d) If CO is added, the equilibrium will shift to the left to relieve the stress. This means that the concentrations of CO and H₂ will decrease, while the concentrations of C and H₂O will increase.

(e) If the temperature of the system is increased, the equilibrium will shift in the endothermic direction to absorb the additional heat. This means that the concentrations of CO and H₂ will increase, while the concentrations of C and H₂O will decrease.

Answer 2

The equilibrium constant for the water gas reaction is written as K = [CO][H2]/[H2O]. According to Le Chatelier's principle, adding more carbon or removing water vapor will drive the reaction to produce more carbon monoxide and hydrogen gas, while adding carbon monoxide or increasing temperature will have the opposite effect.

Step-by-step explanation:

The equilibrium constant expression for the reaction C(s) + H2O(g) ⇌ CO(g) + H2(g) is K = [CO][H2]/[H2O]. The delta H (ΔH) for the reaction is -131.30 kJ, indicating an exothermic process.

• (b) Adding more C (carbon) to the system will drive the reaction towards the right, increasing the concentrations of CO (carbon monoxide) and H2 (hydrogen gas) according to Le Chatelier's principle.
• (c) Removing H2O (water vapor) from the system will also drive the reaction towards the right, increasing the concentrations of CO and H2.
• (d) Adding CO to the system will drive the reaction towards the left, increasing the concentration of water vapor and decreasing the concentration of hydrogen gas.
• (e) Increasing the temperature of the system will favor the endothermic direction of the reaction, which in this case is towards the left since the reaction is exothermic; therefore, the concentrations of CO and H2 will decrease while the concentration of H2O will increase.