Question

On analysis of 3.4 mg of an organic compound, 8.03 g of CO2 and 3.34 g of H2O were obtained. The percentage composition of carbon and hydrogen in the compound are.......................... respectively​

Answer 1

Answer: The percentage composition of carbon and hydrogen in the compound are 64.4 % and 10.9 % respectively​

Explanation:

Mass of $CO_2$ = 8.03 g

Mass of $H_2O$= 3.34 g

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 8.03 g of carbon dioxide, =$\frac{12}{44}\times 8.03=2.19g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 3.34 g of water, =$\frac{2}{18}\times 3.34=0.371g$ of hydrogen will be contained.

Mass of oxygen in the compound = (3.4) - (2.19+0.371) = 0.839 g

percent composition of C =$\frac{\text{mass of C}}{\text{ Total mass}}\times 100= \frac{2.19}{3.4}\times 1000=64.4\%$

percent composition of H =$\frac{\text{mass of H}}{\text{ Total mass}}\times 100= \frac{0.371}{3.4}\times 1000=10.9\%$

Thus the percentage composition of carbon and hydrogen in the compound are 64.4 % and 10.9 % respectively​