I got you. Alright let's start with the Gibbs free energy equation. DeltaG= DeltaH -(T)DeltaS ... Delta H is the heat of formation times 2 since there are two moles! Temperature should be converted to Kelvin so 25 C is 298K. Then delta S is the Sum of Delta S of the mols of products minus sum of Delta S reactants. That gives you 25. Then the 1 x 10-3 is to convert J from the entropy to kJ from the enthalpy. It is hard to type out but I hope that helped!