How many grams of Cu are obtained by passing a current of 12 A through a solution of CuSO₄ for 15 minutes? A)0.016 B)3.6 C)7.1 D)14 E)1.8

Question

Quizplus · Accepted Answer

We can use Faraday's law of electrolysis to calculate the amount of copper deposited at the cathode:

moles of Cu = (current in amperes) x (time in seconds) / (number of electrons per Cu ion)

Since we have 15 minutes = 900 seconds, and Cu2+ ions each gain 2 electrons to form Cu atoms, we can plug in the values:

moles of Cu = (12 A) x (900 s) / (2 electrons/Cu2+ ion) / (96,485 coulombs/mol of electrons) = 0.0074 moles of Cu

To convert moles to grams, we need to multiply by the molar mass of copper which is 63.5 g/mol:

mass of Cu = 0.0074 moles x 63.5 g/mol = 0.47 g or 0.47 x 10^3 mg

Therefore, the answer is B) 3.6 grams (rounded to one decimal place).

How Many Grams of Cu Are Obtained by Passing a Current