Suppose you have the following reaction at equilibrium:

Question

N2(g) + 3H2(g) = 2NH3(g), ΔH = −22 kcal/mol

What changes are expected to occur if the temperature of the system was decreased. You may select multiple answers.


The concentration of NH3(g) would decrease

The concentration of NH3(g) would increase

The concentration of N2(g) would decrease

The concentration of H2(g) would decrease

No change in the equilibrium would occur.

The concentration of H2(g) would increase

Answer 1

Le Chatelier's Principle tells us that if we do something to a system at equilibrium that the system will react so as to undo what we did to it. I will rewrite the equation like this,
N2(g) + 3H2(g) ==> 2NH3(g) + heat.

So if we decrease T, it will try to increase T. How can it do that. More N2 and H2 can react to produce more NH3 and heat. So N2 will decrease, H2 will decrease, NH3 will increase, and the system will shift to the right. Pick out the choices that meet this reaction.