Question

What is the percentage of hydrogen in ${\mathrm{H}}_2\mathrm{O}$?

Answer 1

Step1. Formula for the percentage of hydrogen in ${\mathrm{H}}_2\mathrm{O}$

$\text{Mass percentage of hydrogen=}\frac{\text{Mass of hydrogen}}{{\text{Total mass of H}}_{\text{2}}\text{O}}\text{×100}$

Step2. Calculation of percentage of hydrogen in ${\mathrm{H}}_2\mathrm{O}$

$$\begin{gathered} \text{Mass percentage of hydrogen=}\frac{2\times 1.00784}{18}\text{×100} \\ =\frac{2.01568{\text{g mol}}^{-1}}{18{\text{g mol}}^{-1}}\text{×100} \\ =11.19 \end{gathered}$$

Hence, the percentage of hydrogen in ${\mathrm{H}}_2\mathrm{O}$ is $11.19\%$.