what is △G for the following reaction at 298 K? 2C6H6(l)+15O2(g)-->12CO2(g)+6H2O

Answer 1

We need more information. You probably have a table for ∆G_f for the reactants and the products. You then sum the products, and the reactants and take the difference. It will basically be

12 x CO2 + 6 x H2O - 2 x C6H6 + 0 because ∆Gf for O2 is zero.

Again, if you have the actual values, resubmit the problem and we'll help you.