I got 1.11 x 10^-6 for K.
Here is my work:
x= 0.004
-2x= -0.008 (change for CH4)
Equilibrium for CH4 is 0.087 - 0.008= 0.079
Change in eq for C2H2 is 0.004 and eq is 0.004 (=x)
Change in eq for H2 is 0.012
Eq for H2 is 0.012
K= [C2H2][H2]^3/[CH4]^2
K= (0.004)(0.012)^3/(0.079)^2
K= 1.11 x 10^-6
The reaction of CH4 in
2CH4(g) ---->/<---- C2H2(g) + 3 H2 (g)
is carried out at a different temperature with an initial concentration of [CH4]=0.087M. At equilibrium, the concentration of H2 is 0.012 M. Find the equilibrium constant at this temperature.
Chemistry - DrBob222, Monday, February 29, 2016 at 10:59am
.........2CH4 ==> C2H2 + 3H2
I ......0.087......0......0
C........-2x.......x......3x
E.....0.087-2x.....x......3x
The problem tells you that 3x = 0.012 which allows you to calculate x and 0.087-2x (as well as 3x). Substitute those values into the Keq expression and evaluate Keq.
That looks ok to me.
To find the equilibrium constant (K) at a given temperature, you need to use the concentrations of the reactants and products at equilibrium. From the information given in the question, we can determine the initial concentration of CH4 is 0.087 M and the concentration of H2 at equilibrium is 0.012 M.
To calculate the equilibrium concentrations, you need to understand the stoichiometry of the reaction. The balanced equation for the reaction is:
2CH4(g) ↔ C2H2(g) + 3H2(g)
Using an ICE table, we can set up the initial, change, and equilibrium concentrations for the reaction.
I ......0.087......0......0
C........-2x.......x......3x
E.....0.087-2x.....x......3x
The -2x, x, and 3x represent the changes in concentration for CH4, C2H2, and H2, respectively. The equilibrium concentrations can be calculated by subtracting the change in concentrations from the initial concentrations.
According to the problem, we are given that the concentration of H2 at equilibrium is 0.012 M, so we can equate 3x to 0.012 and solve for x.
3x = 0.012
x = 0.012/3 = 0.004 M
Now we can substitute the equilibrium concentrations into the equilibrium constant expression to solve for K.
K = [C2H2][H2]^3/[CH4]^2
K = (0.004)(0.012)^3/(0.087-2*0.004)^2
K = 1.11 x 10^-6
Therefore, the equilibrium constant (K) at this temperature is 1.11 x 10^-6.