Question

What is the molar mass of sodium carbonate, $\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$)?

Answer 1

Step1. Molar mass

The mass of $1$ mole of a substance is called its molar mass.

Step2. Formula for molar mass

Molar mass =$\text{The atomic mass of element × number of atoms given in subscript}$

Step3. Molar mass of Sodium carbonate$\left({\mathrm{Na}}_2{\mathrm{CO}}_3\right)$

Molar mass of ${\mathrm{Na}}_2{\mathrm{CO}}_3$=$\left(2\times \mathrm{The}\mathrm{atomic}\mathrm{mass}\mathrm{of}\text{Na+}\mathrm{The}\mathrm{atomic}\mathrm{mass}\mathrm{of}\text{C+}\left(\text{3×}\mathrm{The}\mathrm{atomic}\mathrm{mass}\mathrm{of}\text{O}\right)\right)$

=$\left(2\times 22.99{\text{g mol}}^{-1}{\text{+12.01 g mol}}^{-1}\text{+}\left(\text{3×16.00}\right){\text{g mol}}^{-1}\right)$

=$105.99{\text{g mol}}^{-1}\hspace{0.17em}$

Hence, the molar mass of ${\mathrm{Na}}_2{\mathrm{CO}}_3$ is $105.99{\text{g mol}}^{-1}\hspace{0.17em}$.