Question

The density of liquid mercury is $13.6/c{m}^3$. How many moles of mercury are there in $1$ litre of the metal ? (Atomic mass of Hg = $200$)

• A. 55
• B. 13.6
• C. 68
• D. none of these

Answer 1

The correct option is C 68

The density of liquid mercury is $13.6g/c{m}^3$.
1 L (1000 mL) of metal corresponds to $13.6g/c{m}^3\times 1000c{m}^3=13600g$.
Atomic mass of Hg = 200 g/mol.
The number of moles of mercury present in 13600 g are $\frac{13600g}{200g/mol}=68mol$.