Question

$0.2964\,g$ of $Cu$ was deposited on passage of a current of $0.5\,amp$ for $30\,\min$ , through a solution of copper sulphate. Calculate the atomic weight of $Cu$ .
Give your answer by rounding off the value to two significant figures.

Answer 1

Given:
Weight of copper deposited $w=0.2964\,g$
Current $i=0.5\,amp$
Time $t=30\,\min$
For, $Cu^{2 +} \rightarrow Cu$ .
From Faraday's law of electrolysis:
$w=Zit$
$Z=\frac{M_{Cu}}{2 \times 96500}$
$0.2964=\frac{M_{Cu}}{2 \times 96500}\times 0.5\times 30\times 60$
$M_{Cu}=63.56.$