Question

Calculate the formula mass of Zinc oxide $\left(\mathrm{ZnO}\right)$.

Given: Atomic masses of Zn = 65u, 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 Zn = 65u, O= 16u

Step 2: Finding the formula mass for the given data

The formula mass of $\left(\mathrm{ZnO}\right)$ = (Number of zinc atoms x atomic mass of zinc) + (Number of oxygen atoms x atomic mass of oxygen)

The formula mass of $\left(\mathrm{ZnO}\right)$ = $\left(1\times 65\right)+\left(1\times 16\right)$

The formula mass of $\left(\mathrm{ZnO}\right)$ = $65+16=81$g/mol

Hence, the formula mass of Zinc oxide $\left(\mathrm{ZnO}\right)$ is $81$g/mol