Find the equilibrium concentrations of A, B, and C for a=1, b=1, and c=2. Assume that the initial concentrations of A and B are each 1.0 M and that no product is present at the beginning of the reaction.
aA(g)+bB(g)⇌cC(g), Kc = 4.0

Question

Find the equilibrium concentrations of A, B, and C for a=1, b=1, and c=2. Assume that the initial concentrations of A and B are each 1.0 M and that no product is present at the beginning of the reaction.
aA(g)+bB(g)⇌cC(g), Kc = 4.0

alphadxg · Answer

A	B	C
Initial Concentration	1.0M	1.0M	0.0M
Change in Concentration	-x	-x	+2x
Equilibrium Concentration	1-x	1-x	2x

4.0 = C^2/(A)(B)
C=2x, A=B=1-x
4.0=[(2x)^2]/[(1-x)^2]
4(1-x)^2=4x^2
4-4x^2=4x^2
8x^2=4
x^2=4/8=1/2
x=0.707

Equilibrium Concentrations
A: 1-x=1-0.707=0.293 M
B: 1-x=0.293 M
C: x=1.414 M