Here is an example to do the self test at the end of the photo

Book is atkins edition 11

Physical chemistry

answer is +0.76 V

Evaluating a standard potential from two others Given that the standard potentials of the Cu2+/Cu and. Cu/Cu couples are +0.340V and +0.522V, respectively, evaluate E(Cu2+,Cu+). Collect your thoughts. First, note that reaction Gibbs energies may be added (as in a Hess's law analysis of reaction enthalp. ies). Therefore, you should convert the E values to G values by using eqn 6C.3(FE=,G), add them appropriately, and then convert the overall ,G to the required E by using eqn 6C.3 again. This roundabout procedure is necessary because, as seen below, although the factor F cancels (and should be kept in place until it cancels), the factor v in general does not cancel. The solution The electrode half-reactions are as follows: (a) Cu2+(aq)+2eCu(s) E(a)=+0.340V,soG(a)=2(0.340V)F (b) Cu+(aq)+eCu(s) E(b)=+0.522V,so,G(b)=(0.522V)F The required reaction is (c) Cu2+(aq)+eCu+(aq)E(c)=,G(c)/F Because (c)=(a)(b), the standard Gibbs energy of reaction (c) is G(c)=,G(a)G(b)=(0.680V)F(0.522V)F=(0.158V)F Therefore, E(c)=G(c)/F=+0.158V. Self-test 60.2 Evaluate Et(Fe3t,Fe2+) from E(Feln,Fe) and E(Fe3,Fe)