Use the reaction to answer the question.
N₂ (g) + 3H₂ (g) ⇄ 2NH₃ (g) + energy
A student finds this reaction is already at equilibrium. Which change will happen if the student decreases the temperature?
a) The rate of the reverse reaction will increase, raising the temperature in response.
b) The rate of the forward reaction will increase, lowering the temperature even more.
c) The rate of the reverse reaction will increase, lowering the temperature even more.
d) The rate of the forward reaction will increase, raising the temperature in response.
The answer is c) The rate of the reverse reaction will increase, lowering the temperature even more.
According to Le Chatelier's principle, if a stress is applied to a system at equilibrium, the system will shift in a way that counteracts the stress. In this case, decreasing the temperature is a stress that will cause the system to shift in a way that produces more heat. Since the forward reaction is exothermic (releases heat), the system will shift to the right to produce more heat. This means that the rate of the reverse reaction will increase, which will consume more reactants and produce more products, ultimately lowering the temperature even more.