In the context of equilibrium, what is the effect of changing the volume of a gaseous reaction mixture?

In the context of equilibrium, what is the effect of changing the volume of a gaseous reaction mixture?

• A. The reaction always shifts to the left.
• B. The shift depends on the number of moles of gas on each side of the reaction.
• C. Volume does not affect gaseous reactions.
• D. It increases the temperature of the reaction.

Answer: (B)

In the context of a gaseous reaction at equilibrium, altering the volume of the reaction mixture affects the concentration of the gases involved, and this change can influence the position of the equilibrium based on the principles of Le Chatelier's Principle. This principle states that if a dynamic equilibrium is disturbed by changing the conditions, the equilibrium will shift in a direction that counteracts the change. When the volume of a gaseous reaction mixture is decreased, the pressure increases because the same number of gas molecules now occupies a smaller space. According to Le Chatelier's Principle, the system will adjust by shifting the equilibrium toward the side of the reaction that produces fewer moles of gas, thereby reducing the pressure change. Conversely, if the volume is increased, the pressure decreases, prompting a shift to the side that produces more moles of gas. Thus, the direction of the shift indeed depends on the relative number of moles of gas on each side of the reaction. This is why the correct answer emphasizes that the shift depends on the number of moles of gas on each side of the reaction.

In the context of a gaseous reaction at equilibrium, altering the volume of the reaction mixture affects the concentration of the gases involved, and this change can influence the position of the equilibrium based on the principles of Le Chatelier's Principle. This principle states that if a dynamic equilibrium is disturbed by changing the conditions, the equilibrium will shift in a direction that counteracts the change.

When the volume of a gaseous reaction mixture is decreased, the pressure increases because the same number of gas molecules now occupies a smaller space. According to Le Chatelier's Principle, the system will adjust by shifting the equilibrium toward the side of the reaction that produces fewer moles of gas, thereby reducing the pressure change. Conversely, if the volume is increased, the pressure decreases, prompting a shift to the side that produces more moles of gas.

Thus, the direction of the shift indeed depends on the relative number of moles of gas on each side of the reaction. This is why the correct answer emphasizes that the shift depends on the number of moles of gas on each side of the reaction.