A constant current is passed through a solution containing Cu²⁺(aq)resulting in the deposition of 4.40 g of Cu at the cathode.Assuming a current efficiency of 100%,if this same current is passed through a solution of TcO₄^- for the same amount of time,how many grams of Tc would form at the cathode? A)0.969 g B)1.94 g C)6.78 g D)13.6 g

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Quizplus · Accepted Answer

The molar mass of Cu is 63.55 g/mol, and the molar mass of Tc is 98 g/mol. The number of moles of Cu deposited is 4.40 g / 63.55 g/mol = 0.0693 mol. Since Cu²⁺ requires 2 moles of electrons per mole of Cu, the same number of moles of electrons will deposit Tc from TcO₄^-, which requires 7 moles of electrons per mole of Tc. Therefore, the moles of Tc deposited is 0.0693 mol * (2/7) = 0.0198 mol. The mass of Tc deposited is 0.0198 mol * 98 g/mol = 1.94 g.

A Constant Current Is Passed Through a Solution Containing Cu2+(aq)resulting

A Constant Current Is Passed Through a Solution Containing Cu²⁺(aq)resulting