A constant current of 0.50 A is passed through an electrolytic cell containing CuSO_4(aq) with copper electrodes for 30.0 min.
What is the approximate mass change of the cathode? (Molar mass of Cu = 63.5 g mol^{−1})
a) +0.60 g
b) −0.30 g
c) +0.30 g
d) +0.15 g