Suppose that you have a part that requires a tin coating. You’ve calculated that you need to deposit 3.60 g of tin to achieve an adequate coating. If your electrolysis cell (using Sn²⁺) runs at 2.00 A, how long must you operate the cell to obtain the desired coating?

Strategy

This problem again requires that we use the balanced half-reaction to relate moles of electrons and moles of the deposited substance, in this case tin. It differs from the previous example only in terms of what information we are given and what we must solve for. Because we are given a mass of tin required, we can obtain the moles of tin, and that will tell us the moles of electrons required. We then determine the charge of those electrons with the Faraday constant, and we can use our understanding of electricity to get the time needed at the given current.