Question

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.

Answer 1

100 g of organic compound contains 69 g of C, 4.8 g of hydrogen and 26.2 g of oxygen. 0.2 g of organic compound will contain $\frac{69\times 0.2}{100}=0.138$ g of C.
12 g of C is present in 44 g of $C{O}_2$.
0.138 g of carbon will be present in $\frac{44\times 0.138}{12}=0.506$ g of $C{O}_2$.
0.2 g of organic compound will contain $\frac{4.8\times 0.2}{100}=0.0096$g of hydrogen.
18 g of water contains 2 g of hydrogen.
Hence, $0.0096$ g of hydrogen will be present in $\frac{18\times 0.0096}{2}=0.0864$ g of water
Thus, complete combustion of $0.20$ g of organic compound will produce $0.506$ g of carbon dioxide and $0.0864$ g of water.