## K constant

MorganYun1H
Posts: 59
Joined: Thu Jul 13, 2017 3:00 am

### K constant

How do you know when to use K and Kc because in the homework, there are some problems where the reactants and the products are all gases, but I get it wrong because I used Kc instead of K and vice versa? Also, is it true that the larger K is, the more stable the reaction?

Scott Chin_1E
Posts: 55
Joined: Sat Jul 22, 2017 3:00 am

### Re: K constant

When the problem has has K, it's usually implicit that they are referring to $K_{c}$ or $K_{p}$. You would just have to pay attention to the units in which the initial concentration/pressures are given. If they give the initial numbers with the units M (molarity) you will know that the problem is referring to $K_{c}$ rather than $K_{p}$. If the initial numbers are given with units of pressure (bar, atm, etc.) you know the problem is referring to $K_{p}$ rather than $K_{c}$.