A compound contains 40% carbon, 6.6% hydroaen and 53.33% oxy1en._Its vapour density is 30. Calculate its empirical and molecular formulae.

Explanation

Calculation of empirical formula :
The sum of percentages of C and H in the given compound is not 100. Therefore, it must contain oxygen also. Percentage of O = `100 - (40 + 6.67) = 53.33`. The empirical formula of this compound can be obtained as follows :

`therefore` The empirical formula of the given compound is `CH_(2)O`
Calculation of molecular formula :
Empirical formula mass = `12.01 + (2 xx 1.008) + 16.0 = 30.0` amu
Molecular mass (given) = 30.0 amu Molecular mass
`therefore n=("Molecular mass")/("Empirical formula mass")=30.0/30.0 =1`
`therefore` Molecular formula `=1 xx` Empirical formula =`CH_(2)O`
Hence, the molecular formula of the given compound is the same as its empirical formula and is `CH_(2)O`