Carbon – 82.76% hydrogen – 17.24% Find the molecular formula of a substance.

Molecular formula of the substance: CxNu.

Let the mass of the substance = 100 g, then:

m (C) = 82.76 g.

Let’s find the amount of carbon:

n (C) = m (C) / M (C) = 82.76 g / 12 g / mol = 6.897 mol.

m (H) = 17.24 g.

Let’s find the amount of hydrogen:

n (H) = m (H) / M (H) = 17.24 g / 1 g / mol = 17.24 mol.

Let’s establish the ratio of atoms:

x: y = n (C): n (H) = 6.897: 17.24 = 1: 2.5 = 2: 5

Answer: C2H5.