The equilibrium constant changes with a change in temperature, I am confused as to the directions and why Qc is behaving oppositely of what I think it does(adsbygoogle = window.adsbygoogle || []).push({});

For example, my textbook says a temperature increase favors an endothermic reaction (left to right) and a temperature decrease favors the exothermic direction (from right to left). This is ambiguous to me, I am not sure what they mean by favor, if somone can clarify.

Anyway, here is an endothermic reaction

heat + A ⇔ B + C

If you increase the temperature, the heat is treated as a reactant and it shifts from left to right, that is fine

Exothermic:

A + B ⇔ C + heat

decrease the temperature, shouldnt this shift from left to right, since the heat is treated like a concentration and it is taken away, so to make up for it more is going from left to right, yet the book says right to left.

My other concern is how the equilibrium constant changes with temperature. We had a worksheet and its says heating an endothermic equilibrium system increases K. The answer given is true, and I have 2 thoughts on this.

The first is that if you have an endothermic reaction, heating it up increases the number of the reactant side, so the denominator is bigger and K is lower. However, if you increase the temperature, equilibrium would shift to the right so now the numerator is bigger, and therefore K is bigger. I think the second statement is the correct one, but just want to confirm.

It says cooling an exothermic equilibrium increases K. That mens equilibrium shifts to the right (which contradicts my textbook from above) and the numerator is now bigger, so K is bigger.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Temperature and the equilibrium constant

**Physics Forums | Science Articles, Homework Help, Discussion**