Calculate the change in the entropy of the surroundings in

Question

Question 1: The standard enthalpies of formation, at 25.00 ^oC, of methanol (CH₄O(l)), water (H₂O(l)), and carbon dioxide (CO₂(g)) are, respectively, -238.7 kJ/mol, -285.8 kJ/mol, and -393.5 kJ/mol. Calculate the change in the entropy of the surroundings (in J/K) upon the combustion of 16.5 g of methanol under a constant pressure of 1.000 atm and a temperature of 25.00 ^oC. N.B. combustion is the reaction of this substance with molecular oxygen to produce water and carbon dioxide. 

Question 2: At 25^oC, the equilibrium constant for the reaction 2 A(aq) ----> B(aq) + C(aq) is 2.17 . If the concentration of B(aq) is 0.394 M and the concentration of C(aq) is 0.534 M, what would be the minimal concentration of A(aq) (in mol/L) required to make the reaction spontaneous? 

Question 3: For the reaction A(aq) + B(aq) <---> C(aq) + D(aq), the equilibrium constant is 24.9 at 25^oC and 36.2 at 50^oC. What is the value of the standard Gibbs free energy change (in kJ) of this reaction at 75^oC?