One kmol of CO2 is heated at a constant pressure

One kmol of CO2 is heated at a constant pressure of 100 kPa to 3000 K.
(a) Calculate the equilibrium composition of CO2 and use the IGE system state TESTcalc to verify your answers.
(b) Use the n-IG system state TESTcalc and calculate the Gibbs function of the mixture (1-x)CO2 + xCO + (x/2)O2 at 100 kPa, 3000 K for x varying from 0 to 1. Show that for x = 0.438, Gibbs function reaches a minimum.