At 25 °C, the equilibrium partial pressures for the following reaction were found to be PA = 8.00 atm, PB = 5.40 atm, PC = 6.90 atm, and PD = 5.90 atm.
A(g) + 2B(g) -----> C(g) + D(g)
What is the standard change in Gibbs free energy of this reaction at 25 degrees Celsius.