Question

Consider the following reaction:
CO(g)+2H2(g)⇌CH3OH(g)
A reaction mixture in a 5.15 −L flask at a certain temperature contains 26.6 g CO and 2.36 g H2 . At equilibrium, the flask contains 8.67 g CH3OH .

Calculate the equilibrium constant (Kc) for the reaction at this temperature.        

Answer 1

   CO(g) + 2H2(g) <----> CH3OH(g)

initial concentration of CO = (W/MWT)*(1/V)

                            = (26.6/28)*(1/5.15)

                            = 0.184 M

initial concentration of H2 = (W/MWT)*(1/V)

                            = (2.36/2)*(1/5.15)

                = 0.23 M

at equilibrium,

concentration of CH3OH = (8.67/32)*(1/5.15) = 0.0526 M

concentration of CO = 0.184 - 0.0526 = 0.1314 M

concentration of H2 = 0.23 - 2*0.0526 = 0.1248 M

Kc = [CH3OH]/[H2]^2[CO]

     = 0.0526/(0.1314*0.1248^2)

     = 25.7