When the substances in the equation below are at equilibrium at pressure P and temperature T, how can the equilibrium be shifted to favor the products?
CuO(s) + H₂(g)
Cu(s) + H₂O(g)
Change in enthalpy = -2.0 kJ.

Question

When the substances in the equation below are at equilibrium at pressure P and temperature T, how can the equilibrium be shifted to favor the products?
CuO(s) + H₂(g)

Cu(s) + H₂O(g)
Change in enthalpy = -2.0 kJ.

Quizplus · Accepted Answer

According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in temperature, pressure, or concentration, the equilibrium will shift in a way that tends to counteract the change. In this case, since the change in enthalpy is negative, the forward reaction (CuO + H2S → Cu + H2O) is exothermic. Therefore, decreasing the temperature will shift the equilibrium in the direction of the products, because it will favor the endothermic reaction (Cu + H2O → CuO + H2S). Therefore, the best choice is C.

When the Substances in the Equation Below Are at Equilibrium