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A lead storage battery was discharged to flow 0.4 mol of electrons. Find the change of the mass of cathode. The answer should be 12.8 grams.
Accepted Answer
The change in mass of the cathode can be calculated using Faraday's law of electrolysis, which states that the mass of a substance deposited or dissolved at an electrode is directly proportional to the amount of charge passed through the electrode. The equation for Faraday's law is: m = (M * Q) / (n * F) where: m is the mass of the substance deposited or dissolved (in grams) M is the molar mass of the substance (in grams per mole) Q is the charge passed through the electrode (in coulombs) n is the number of electrons transferred per mole of the substance F is the Faraday constant (96,485 coulombs per mole of electrons). In this case, we have: M = 207.2 g/mol (for lead) Q = 0.4 mol * 96,485 C/mol = 38,594 C n = 2 (for lead) F = 96,485 C/mol Plugging these values into the equation, we get: m = (207.2 g/mol * 38,594 C) / (2 * 96,485 C/mol) = 12.8 g Therefore, the change in mass of the cathode is 12.8 grams.
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