Understanding Equilibrium Constants With No Denominator

[yougene]

Lets say you have something like
CaSO4 (s) <-----> Ca (aq) + SO4(aq)

The equilibrium constant would then have no denominator. That makes no sense to me!

K would equal [ Ca ][ SO4 ].

Wouldn't that then represent a constant amount of moles no matter how much CaSO4 is present?

Lets say K = 4 in this case
and [ Ca ] = 2 and [ SO4 ] = 2

Because K isn't a fraction, there is no way to reach equilibrium by balancing the reactant and products. K would then suggest the maximum molarity for a given solution, no matter how much solid reactant is in the solution.

That's how I'm interpreting it but it just seems wrong. Can someone clarify for me?

Thanks

 

[chemisttree]

The concentration of CaSO4 in solid CaSO4 is a constant. Multiplying the inverse of that constant by [ Ca ][ SO4 ] gives you your K. Sometimes the constant is not shown (like in solubility products).