1. The problem statement, all variables and given/known data Write the half-reactions and the overall reaction for the oxidation of water by F2. Determine the standard potential and DeltaGr(0). 2. Relevant equations I can manage the half-reaction and the overall reaction should be: 2 H2O + 2 F2 = 4 HF + O2 3. The attempt at a solution OK the Standard potential should be 2,87(F2/F-) - 1,23 = 1,64 V (why is it 2,87-1,64 not opposite?) And the answer for gibbs is: -(4mol)*(96,485 kC/mol)(1,64 V)=-633kJ I know that the standard gibbs reaction is sum of products molar energy - reactants, but how is it calculated above? and maybe there are other ways to calculate standard gibbs energy, would appreciate if anyone mentions them.