Question

Calculate the mass of $0.2\text{moles}$ of water.$\left[\mathrm{O}=16,\mathrm{H}=1\right]$

Answer 1

Step 1: Given information

$0.2\text{moles}$ of water$\left({\text{H}}_{\text{2}}\text{O}\right)$

Step 2: Calculation of molecular weight of water$\left({\mathrm{H}}_2\mathrm{O}\right)$

Molecular weight of water

$$\begin{gathered} =2\times \text{H+O} \\ =\left(2\times 1+16\right)\text{g} \\ =18\text{g} \end{gathered}$$

Step 3: Calculation of mass of $0.2\text{moles}$ of water

Mass of $1\text{mol}$ of water is $18\text{g}$.

Mass of $0.2\text{moles}$ of water is $\frac{18}{1}\times 0.2\text{=3.6 g}$

Hence, the mass of $0.2\text{moles}$ of water is $3.6\text{g}$.