An organic compound contains $69 \%$ carbon and $4.8 \%$ hydrogen,the remainder being oxygen. Calculate the masses of carbon dioxide and water produced when $0.20 \ g$ of this substance is subjected to complete combustion.

Percentage of carbon in organic compound $= 69 \%$.
$100 \ g$ of organic compound contains $69 \ g$ of carbon.
$\therefore 0.2 \ g$ of organic compound contains $= \frac{69 \times 0.2}{100} = 0.138 \ g$ of $C$.
Molecular mass of $CO_2 = 44 \ g$.
$12 \ g$ of carbon produces $44 \ g$ of $CO_2$.
Therefore,$0.138 \ g$ of carbon produces $\frac{44 \times 0.138}{12} = 0.506 \ g$ of $CO_2$.
Percentage of hydrogen in organic compound $= 4.8 \%$.
$100 \ g$ of organic compound contains $4.8 \ g$ of hydrogen.
$\therefore 0.2 \ g$ of organic compound contains $\frac{4.8 \times 0.2}{100} = 0.0096 \ g$ of $H$.
Molecular mass of $H_2O = 18 \ g$.
$2 \ g$ of hydrogen produces $18 \ g$ of water.
$\therefore 0.0096 \ g$ of hydrogen produces $\frac{18 \times 0.0096}{2} = 0.0864 \ g$ of $H_2O$.