chemistry electrolysis: Finding Joules?

Question

A voltaic cell is based on the following reaction.
Sn(s) + I2(s) Sn2+(aq) + 2 I-(aq)
Under standard conditions, what is the maximum electrical work, in joules, that the cell can accomplish if 81.5 g of Sn is consumed?

please show me how to solve this...if you could go by step and kind of explain i would absolutly be delighted

Answer 1

You have to get the related standard reduction potentials from rference/s:
I2(s) + 2e- ==> 2 I-(aq), Eo = 0.53V
Sn(2+)(aq) + 2e- ==> Sn(s), Eo = -0.14V
Hence the emf of the reaction given is 0.53V+0.14V = 0.67V
Sn(s) + I2(s) ==> Sn2+(aq) + 2 I-(aq)
which is a two-electron transferring process.

Since the molar mass of Sn is: 118.7 g/mol,
81.5g Sn = 0.6866 mol Sn
Remember 1F = 96485C, which is the charge of 1 mole electrons.
Also remember 1 joule = 1 newton-meter = 1 watt-second
= 1 C*V-second.
The requested maximum electrical work is:
(0.6866 mol)*2*(96485C/mol)*(0.67V) = 88.8 kJ