Question

The equilibrium constant for the conversion of cis-stilbene to trans-stilbene is Kc = 24.0 at 200 C. If cis-stilbene is placed in an empty container at an initial concentration of 0.850 mol/L. What is the final concentration of trans-stilbene in the container at equilbrium?

A diagram illustrates cis-stilbene on the left and trans stilbene on the right with a reverse arrow <===> between

The answer is 0.816 mol L-1. What is the formula used and maths steps please.

Thanks

Answer 1

Cis ==> Trans

initial:
Cis = 0.850
trans = 0

change:
trans: +x
cis: -x

equilibrium:
cis = 0.850
trans = +x

Kc = 24.0 = (trans)/(cis)
24.0 = (x)/(0.850-x)
solve for x.