On complete combustion,$0.246 \ g$ of an organic compound gave $0.198 \ g$ of carbon dioxide and $0.1014 \ g$ of water. Determine the percentage composition of carbon and hydrogen in the compound.

The percentage of carbon is calculated as: $\text{Percentage of carbon} = \frac{12 \times \text{mass of } CO_2 \times 100}{44 \times \text{mass of compound}} = \frac{12 \times 0.198 \times 100}{44 \times 0.246} = 21.95 \ \%$.
The percentage of hydrogen is calculated as: $\text{Percentage of hydrogen} = \frac{2 \times \text{mass of } H_2O \times 100}{18 \times \text{mass of compound}} = \frac{2 \times 0.1014 \times 100}{18 \times 0.246} = 4.58 \ \%$.