Question

A sample of hydrocarbon contains 85.7 % carbon and 14.3 % hydrogen by mass. If the molar mass is 56, determine the empirical formula and molecular formula of the compound. [8 marks]​

Answer 1

Answer:

Molecular formula: C4H8

Empirical formula: CH2

Explanation:

56 × 0.857 = 47.992 ~ 48

Ar = Relative atomic mass

Ar of C = 12

48 ÷ 12 = 4

56 × 0.143 = 8.008 ~ 8

Ar of H = 1

8 ÷ 1 = 8

Molecular formula: C4H8

This is the compound butene;

The empirical formula would simply be CH2 as this is the simplest whole number ratio of atoms in the compound.