In: Chemistry
The reaction of CH4 is carried out at a different temperature with an initial concentration of [CH4] = 9.9×10−2 M . At equilibrium, the concentration of H2 is 2.0×10−2 M
2CH4(g)⇌C2H2(g)+3H2(g)
whats the equilibrium constant
Set up the ICE chart for the reactions as below:
2 CH4 (g) <====> C2H2 (g) + 3 H2 (g)
initial 9.9*10-2 0 0
change -2x +x +3x
equilibrium (9.9*10-2 – 2x) x 3x
Given the equilibrium concentration of H2 is 2.0*10-2 M, we must have,
3x = 2.0*10-2
===> x = 6.67*10-3
Therefore, [C2H2]eq = 6.67*10-3 M; [CH4] = (9.9*10-2 – 2*6.67*10-3) M = 0.08566 M.
The equilibrium constant is given by
K = [C2H2][H2]3/[CH4]2 = (6.67*10-3)*(2.0*10-2)3/(0.08566)2 = 7.272*10-6 (ans).