Question

The density of liquid mercury is $13.6{\text{g cm}}^{-3}$. How many moles of mercury are there in 1 litre of the metal? (Atomic mass of $Hg=200$)

Answer 1

Given: Volume of $Hg$ metal $=1000\text{mL}$
$\text{Density},d=13.6{\text{g cm}}^{-3}$
$\because d=\frac{m}{V}$
$\Rightarrow m=13.6{\text{g mL}}^{-1}\times 1000\text{mL}=13600\text{g}$
No. of moles of $Hg$ metal $=\frac{13600}{200}=68$