Calculate the mass of iron in 10 kg of iron ore which contains 80% of pure ferric oxide.

If the empirical formula of two compounds is CH and their Vapour densities are 13 and 39 respectively, find their molecular formula.

On analysis, a substance was found to contain :

C = 54.54%, H = 9.09%, O = 36.36%

The vapour density of the substance is 44, calculate :

(a) (a) its empirical formula,

(b) its molecular formula.

An organic compound, whose vapour density is 45, has the following percentage composition,

H = 2.22%, O = 71.19% and remaining carbon.

Calculate :

(a) its empirical formula,

(b) its molecular formula.