How much copper can be obtained from 100 g of copper sulphate (${\mathrm{CuSO}}_4$)?

$\text{ Molar mass of }{\mathrm{CuSO}}_4=63.54+32.06+(4\times 16)$

                                    $=159.6 \mathrm{g}{ \mathrm{mol}}^{-1}$

$159.6 \mathrm{g} {\mathrm{CuSO}}_4\text{ contain }=63.54 \mathrm{g} \mathrm{Cu}$

$1\mathrm{g} {\mathrm{CuSO}}_4\text{ contain }=\frac{63.54}{159.6}\mathrm{g} \mathrm{Cu}$

$\therefore 100 \mathrm{g} {\mathrm{CuSO}}_4\text{ contains }=\frac{63.54\times 100}{159.6}$

$=39.81 \mathrm{g} \mathrm{Cu}$