Question #910ee

1 Answer
Oct 4, 2016

Given 0.44g of sample on combustion produces 0.88g CO_2CO2
We know molar mass of CO_2=44" g/mol"CO2=44 g/mol which contains 12g carbon.

So 0.88g CO_2CO2 will contain

(0.88xx12)/44g=0.24g" "C0.88×1244g=0.24g C

Similarly molar mass of H_2O=18" g/mol"H2O=18 g/mol which contains 2g hydrogen.

So 0.36g H_2OH2O will contain

(2xx0.36)/18g=0.04g" " H2×0.3618g=0.04g H

So the remaing amount in 0.88g of sample (0.88-0.24-0.04)g=0.16g(0.880.240.04)g=0.16g must be Oxygen.

Given molar mass of sample 132" g/mol"132 g/mol

Hence 1 mole or 132g of the sample will contain

C->(0.24xx132)/0.44g=72g=(72g)/(12g/"mol")=6" mol"C0.24×1320.44g=72g=72g12gmol=6 mol

H->(0.04xx132)/0.44g=12g=(12g)/(1g/"mol")=12" mol"H0.04×1320.44g=12g=12g1gmol=12 mol

O->(0.16xx132)/0.44g=48g=(48g)/(16g/"mol")=3" mol"O0.16×1320.44g=48g=48g16gmol=3 mol

Hence the molecular formula of the sample is-" "C_6H_12O_3 C6H12O3