Question

Consider the following reaction and associated equilibrium constant: aA(g)+bB(g)⇌cC(g), Kc = 3.0 Part A 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. Express your answer using two significant figures. Enter your answers separated by commas. [A], [B], [C] = m M

Answer 1

Reaction: aA(g) + bB(g) <-> cC(g)
Equilibrium Constant (Kc) = 3.0
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.

	A	B	C
Initial Concentration	1.0M	1.0M	0.0M
Change in Concentration	-x	-x	+2x
Equilibrium Concentration	1-x	1-x	2x

3.0=(2x)^2/[(1-x)^2]
3(1-x)^2=4x^2
solving the above equation we get
x=0.464

but the question wants to know the concentrations
1-x = .536

So therefore
[A]=0.536 M = 536 mM

[B]=0.536 M = 536 mM

[C]= 0.928 M = 928 mM