Equilibrium Constant

$PV=nRT$

Victoria Luu - 1C
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Equilibrium Constant

Why are solids and liquids not used in calculating the equilibrium constant? Do you only use the concentration when the reactants and products are aqueous, or can you also use it when it is a gas

inlovewithchemistry
Posts: 104
Joined: Fri Sep 28, 2018 12:19 am

Re: Equilibrium Constant

Both gaseous and aqueous reactants and products can be used when calculating K or Q. We cannot use solids or liquids as they do not effect the amount of products or reactants at all, so we keep them at value=1.

Diana Bibireata 1B
Posts: 60
Joined: Fri Sep 28, 2018 12:23 am

Re: Equilibrium Constant

The molar concentrations of solids and liquids do not change in a reaction and therefore are not used to calculate the equilibrium constant. On the other hand, both gases and aqueous solutions are used to calculate the equilibrium constant.

caseygilles 1E
Posts: 73
Joined: Fri Sep 28, 2018 12:18 am

Re: Equilibrium Constant

The concentration of Pure solids and liquids are not used in calculating the equilibrium constant because their concentrations stay constant throughout the reaction. We can see this because their concentrations are calculated by density/ molar mass. The activity ion pure solids and liquids is therefore said to be equal to 1 because the concentrations would be the same in the numerator and denominator.