Consider the following reaction at equilibrium:
C(s) + H2O(g) CO(g) + H2(g)
Predict which of these stresses which cause the equilibrium system to shift towards the reactant side (to the left). (There may be more than one correct answer - choose ALL of the correct choices.)
a. C is added to the reaction mixture.
b. H2O is condensed and removed from the reaction mixture.
c. CO is added to the reaction mixture.
d. H2 is removed from the reaction mixture.
To determine which stresses will cause the equilibrium system to shift towards the reactant side (to the left), we need to analyze Le Chatelier's principle. Le Chatelier's principle states that when a system at equilibrium is subjected to a change in temperature, pressure, or concentration, it will respond by shifting in the direction that minimizes the effect of the change.
Let's analyze each choice:
a. C is added to the reaction mixture:
Adding more C (carbon) to the reaction mixture will increase the concentration of the reactant on the left side of the equation (C). According to Le Chatelier's principle, to minimize this increase in concentration, the equilibrium system will shift towards the left (reactant side).
b. H2O is condensed and removed from the reaction mixture:
Removing water vapor (H2O) from the reaction mixture will decrease the concentration of the product on the right side of the equation (CO and H2). To counteract this decrease, the equilibrium system will shift towards the left to replenish the lost product. Therefore, the system will shift towards the reactant side.
c. CO is added to the reaction mixture:
Adding more CO (carbon monoxide) to the reaction mixture will increase the concentration of the product on the right side of the equation (CO and H2). To minimize this increase in concentration, the equilibrium system will shift towards the left (reactant side).
d. H2 is removed from the reaction mixture:
Removing hydrogen gas (H2) from the reaction mixture will decrease the concentration of the product on the right side of the equation (CO and H2). To counteract this decrease, the equilibrium system will shift towards the left to replenish the lost product. Therefore, the system will shift towards the reactant side.
Based on this analysis, the correct choices that will cause the equilibrium system to shift towards the reactant side (to the left) are:
a. C is added to the reaction mixture.
b. H2O is condensed and removed from the reaction mixture.
c. CO is added to the reaction mixture.
d. H2 is removed from the reaction mixture.