Question

0.30 g of a substance gives 0.88 g of carbon dioxide and 0.54 g of water calculate the percentage of carbon and hydrogen in it.

Answer 1

Weight of organic compound = 0.30 g

Weight of carbon-dioxide = 0.88 g

Weight of water = 0.54 g

Percentage of hydrogen:

18 g of water contains 2 g of hydrogen

0.54 g of water contain = \(\frac{2}{18}\) x 0.54 g of hydrogen

% of hydrogen = \(\frac{2}{18}\) x \(\frac{0.54}{0.30}\) x 100 = \(\frac{2}{18}\) x \(\frac{54}{0.3}\)

% of H = 0.111 x 180 = 19.888 ≈ 20%

Percentage of carbon:

44 g of CO₂ contains 12 g of carbon

0.88 g of CO₂ contains = \(\frac{12}{44}\) x 0.88 g of carbon

% of carbon = \(\frac{12}{44}\) x \(\frac{0.88}{0.30}\) x 100 = \(\frac{12}{44}\) x \(\frac{88}{0.3}\) = \(\frac{24}{0.3}\)

% of carbon = 80 % .