## Calculating K

Tiffany Wu 1K
Posts: 19
Joined: Wed Sep 21, 2016 2:56 pm

### Calculating K

When calculating the equilibrium constant, what do you do if one of the reactants or products are a liquid or solid?

Posts: 21
Joined: Sat Jul 09, 2016 3:00 am

### Re: Calculating K

Liquids and solids are not included when trying to find the equilibrium constant. The molar concentration of a pure solid or liquid will not change in a reaction and therefore are disregarded.

Drake_Everlove_1K
Posts: 19
Joined: Sat Sep 24, 2016 3:02 am

### Re: Calculating K

One of our questions on the quiz seems to want us to do this. Question 8 on Fall 2014 prep says:

Considering NH4HS(s) <--> NH3(g) + H2S(g)

If Kp is 0.11 at 300K, calculate the equilibrium partial pressure of NH3(g) starting from pure NH4HS(s).

Maggie Bui 1H
Posts: 35
Joined: Fri Jul 22, 2016 3:00 am
Been upvoted: 1 time

### Re: Calculating K

Even if there's a solid in the reaction, you can still calculate the Q and K using just the concentrations of the reactants and or products in gas phase.

Chem_Mod
Posts: 18400
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 435 times

### Re: Calculating K

When calculating equilibrium constants, we treat the concentrations of pure liquids and solids as if they were always exactly 1.