Question

calculate no. of molecules present in 7.1 g of chlorine.

Answer 1

Molar mass of chlorine (Cl₂) = 71 g mol^-1
Given mass of Chlorine = 7.1 g
71 g of chlorine contains = 6.022$\times$10²³ molecules
7.1 g of chlorine contains = $\frac{6.022\times {10}^{23}}{71}\times 7.1$ = 0.6022$\times$10²³ molecules