Question

Without doing a numerical calculation, determine which of the following will reduce the free energy change for the reaction, that is, make it less positive or more negative, when the temperature is increased. Explain.

a) N₂(g)+3H₂O(G) → 2NH₃(g)

b) HCl(g)+NH₃(g) → NH₄Cl(s)

Answer 1

Increasing the temperature will increase the free energy change for N₂(g) + 3H₂O(G) → 2NH₃(g), while it will decrease the free energy change for HCl(g) + NH₃(g) → NH₄Cl(s).

Step-by-step explanation:

For the first reaction, N₂(g) + 3H₂O(G) → 2NH₃(g), increasing the temperature will increase the free energy change for the reaction. This is because the reaction is exothermic, meaning it releases heat, and according to Le Chatelier's principle, the reaction will shift in the direction that consumes heat. If the temperature is increased, the reaction will shift more towards the reactants, resulting in a less negative or more positive change in free energy.

For the second reaction, HCl(g) + NH₃(g) → NH₄Cl(s), increasing the temperature will decrease the free energy change for the reaction. This is because the reaction is exothermic, but in this case, the reaction involves the formation of a solid NH₄Cl. As the temperature increases, the reaction will shift towards the products to minimize the increase in temperature, resulting in a less positive or more negative change in free energy.