A current of 9.65 A is passed for 2000 s through a solution of a zinc salt, where each Zn ion gains 2 electrons. What mass of zinc is deposited? (F = 96500 C/mol; molar mass 65 g/mol)
Answer and explanation
Correct answer: B. 6.5 g
- Step 1: Charge Q = It = 9.65 × 2000 = 19300 C, which is 0.2 mol of electrons. Step 2. Moles of metal = 0.2 ÷ 2, so mass = 6.5 g. Answer: 6.5 g. Why not the others: 13 g is what you get if you forget to divide by the electrons per ion. 3.25 g is what you get if you divide by the electrons twice. 65 g is what you get if you misplace a power of ten.
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