Exactly 1.0 mol N2O4 is placed in an empty 1.0-L container and is allowed to reach equilibrium described by the equation N2O4(g) ↔ 2NO2(g) If at equilibrium the N2O4 is 37% dissociated, what is the value of the equilibrium constant, Kc, for the reaction under these conditions?

Respuesta :

Answer : The equilibrium constant [tex]K_c[/tex] for the reaction is, 0.869

Explanation :

First we have to calculate the concentration of [tex]N_2O_4[/tex].

[tex]\text{Concentration of }N_2O_4=\frac{\text{Moles of }N_2O_4}{\text{Volume of solution}}[/tex]

[tex]\text{Concentration of }N_2O_4=\frac{1.0moles}{1.0L}=1.0M[/tex]

The balanced equilibrium reaction is,

                          [tex]N_2O_4(g)\rightleftharpoons 2NO_2(g)[/tex]

Initial conc.        C                 0

At eqm. conc.     [tex](C-C\alpha)[/tex]               [tex](2C\alpha)[/tex]

As we are given,

The percent of dissociation = [tex]\alpha[/tex] = 37 %  = 0.37

Now we have to calculate the equilibrium constant for the reaction.

The expression of equilibrium constant for the reaction will be :

[tex]K_c=\frac{[NO_2]^2}{[N_2O_4]}[/tex]

[tex]K_c=\frac{(2C\alpha)^2}{(C-C\alpha)}[/tex]

Now put all the values in this expression, we get :

[tex]K_c=\frac{(2\times 1.0\times 0.37)^2}{(1.0-1.0\times 0.37)}[/tex]

[tex]K_c=0.869[/tex]

Therefore, the equilibrium constant [tex]K_c[/tex] for the reaction is, 0.869