For the following equilibria, use Le Châtelier's principle to predict the direction of the reaction when the pressure is increased by decreasing the volume of the equilibrium mixture.
a. C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

Verified step by step guidance

1. Identify the states of matter for each species in the equilibrium reaction: C(s) is a solid, H2O(g) is a gas, CO(g) is a gas, and H2(g) is a gas. Le Châtelier's principle primarily applies to gases when considering pressure changes.
2. Count the number of moles of gas on each side of the equilibrium. On the left side, there is 1 mole of gas (H2O(g)), and on the right side, there are 2 moles of gas (CO(g) and H2(g)).
3. Recall Le Châtelier's principle: When the pressure is increased (by decreasing the volume), the equilibrium will shift in the direction that reduces the total number of gas molecules to counteract the change.
4. Compare the number of gas molecules on each side. Since the left side has fewer gas molecules (1 mole) than the right side (2 moles), the equilibrium will shift toward the side with fewer gas molecules to reduce pressure.
5. Conclude that the reaction will shift to the left (toward the reactants) when the pressure is increased by decreasing the volume of the equilibrium mixture.

Key Concepts

Le Châtelier's Principle

Le Châtelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust itself to counteract that change and restore a new equilibrium. This principle is crucial for predicting how a reaction will respond to changes in concentration, temperature, or pressure.

Equilibrium and Reaction Quotient

In a chemical reaction at equilibrium, the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. The reaction quotient (Q) helps determine the direction in which the reaction will shift when conditions change, allowing us to predict how the system will respond to pressure changes.

Effect of Pressure on Gaseous Reactions

In reactions involving gases, increasing the pressure by decreasing the volume favors the side of the equilibrium with fewer moles of gas. This is because the system will shift to reduce the pressure, thus understanding the mole ratio of gaseous reactants and products is essential for predicting the direction of the shift.