Nitrogen dioxide, NO2, dimerizes easily to form dinitrogen tetroxide , N2O4 :

Question

2NO2<===>N2O4
a) Calculate Change in reaction G* and K for this equilibrium.
b) Calculate the (e) (the measure of the progress of the reaction) for this equilibrium if 1.00 mol NO2 were present initially and allowed to come to equilibrium with the dimer in a 20.0 l system?

Answer 1

delta Gorxn = (n*DGoproducts)-(DGoreactants), then
delta Go = -RT*lnKp.
I would then convert this to Kc by
Kp = Kc(RT)^{delta n}

I don't know what you mean by (e).
.............2NO2 ==> N2O4
initial......1 mol.....0
change......-2x........x
equil........1-2x.......x

Kc = (N2O4)/(NO2)^2
Don' forget to convert mole to M by moles/L and that is a 20.0 L container.