Question

Complete combustion of 750 g of an organic compound provides 420 g of $CO_2$ and 210 g of $H_2O$.

The percentage composition of carbon and hydrogen in organic compound is 15.3 and _______ respectively. (Round off to the Nearest Integer)

Answer 1

3

Answer 2

To determine the percentage composition of hydrogen in the organic compound, we use the mass of water produced during complete combustion.

1. Calculate the mass of Hydrogen from H₂O: The molar mass of H₂O is 18 g/mol (2 g for H and 16 g for O). 18 g of H₂O contains 2 g of Hydrogen. Given that 210 g of H₂O is produced.

Mass of Hydrogen (H) = (Mass of H in H₂O / Molar mass of H₂O) × Mass of H₂O produced Mass of H = $\frac{2}{18} \times 210 \text{ g}$ Mass of H = $\frac{1}{9} \times 210 \text{ g}$ Mass of H = $23.333 \text{ g}$

2. Calculate the percentage of Hydrogen in the organic compound: The total mass of the organic compound is 750 g.

Percentage of Hydrogen (%H) = $\frac{\text{Mass of H}}{\text{Mass of organic compound}} \times 100$ %H = $\frac{23.333 \text{ g}}{750 \text{ g}} \times 100$ %H = $0.03111 \times 100$ %H = $3.111 \%$

3. Round off to the Nearest Integer: Rounding 3.111% to the nearest integer gives 3%.

The percentage composition of carbon and hydrogen in organic compound is 15.3 and 3 respectively.