The passage of a current of 1.500 A for 50.00 minutes deposited 1.476g of copper from Cu(NO3)2 solution. From this information calculate the atomic mass of copper.
The copper in Cu(NO3)2 is Cu2+. So if you add two electrons, you can reduce it to copper metal Cu(s), +0 charge. You get the electrons by passing the current through your solution. Now it's kind of like a moles to mass problem, only you are talking about moles of electrons. (Cu2+) + 2e- ->>> Cu(s) By definition, an Amp is 1 Coulomb per second. So 1.5Amps*(3000 seconds) = 4500 Coulombs of charge you added to the solution. Faradays constant is 96485.309 Columbs per (mole of electrons). So 4500 C / (96485.309 C/mole electrons) = .0466 moles of electrons added. From the stoichiometry, that means you reduced 0.466/2 = 0.0233 moles of copper. Finally, this 0.0233 moles of copper weighed 1.476 grams. So 1.476g/0.0233 moles: 63.294 g/mole Cu! This is a little off of the actual value of 63.546g/mole, so either I rounded somewhere or this wasn't a perfect experiment. This kind of experiment is a coulometric titration.
