Question

.${10}^{22}$atoms of an element 'X' arefound to have a mass of 930 mg. Calculate the molar massof the element ‘X’.

Answer 1

• The molar mass of an element is the mass of Avogadro's number of atoms.
• ${10}^{22}$ atoms of the element have mass $=930\mathrm{mg}=\frac{930}{1000}g=0.930g$
• So $6.022\times {10}^{23}$atoms will have mass$=\frac{0.930}{{10}^{22}}\times 6.022\times {10}^{23}\mathrm{g}$

$=56.0\mathrm{g}$

• Hence the molar mass of the element =$=56\mathrm{gmo}{\mathrm{l}}^{-1}$