Question

Calculate the formula mass of Sodium nitrate $\left({\mathrm{NaNO}}_3\right)$.

Given: Atomic masses of Na = 23u, N = 14u, 0 = 16u

Answer 1

Step 1: Calculating the formula mass

Formula mass is equal to the sum of atomic masses of all the atoms (or ions) present in a molecule of an ionic compound.

Step 2: Given data

Atomic masses of Na = 23u, N = 14u, O = 16u

Step 2: Finding the formula mass for the given data

The formula mass of $\left({\mathrm{NaNO}}_3\right)$ = (Number of sodium atoms x atomic mass of sodium) + (Number of nitrogen atoms x atomic mass of nitrogen) + (Number of oxygen atoms x atomic mass of oxygen)

The formula mass of $\left({\mathrm{NaNO}}_3\right)$ = $\left(1\times 23\right)+\left(1\times 14\right)+\left(3\times 16\right)$

The formula mass of $\left({\mathrm{NaNO}}_3\right)$ = $23+14+48=85$g/mole

Hence, the formula mass of Sodium nitrate $\left({\mathrm{NaNO}}_3\right)$ is $85$g/mole