During the combustion of 4 g of the substance, 11 g of carbon dioxide and 9 g

During the combustion of 4 g of the substance, 11 g of carbon dioxide and 9 g of water were obtained. Find the formula of a substance if the density for oxygen is 0.5

M (CxHyOz) = 0.53 * 32g / mol = 16g / mol.

n (H2O) = 9g / 18g / mol = 0.5 mol.

n (CO2) = 11g / 46g / mol = 0.25 mol.

n (H) = 2n (H2O) = 2 * 0.5 mol = 1 mol.

n (C) = n (CO2) = 0.25 mol.

Let’s check the oxygen content in organic matter:

m (C) = 0.25 mol * 12 g / mol = 3 g.

m (H) = 1 mol * 1 g / mol = 1 g.

m (O) = m (СxHyOz) – m (H) – m (C) = 4g-3g-1g = 0g.

Therefore, there is no oxygen in organic matter, then we can find the simplest formula for the substance, we will compose the ratio:

n (C): n (H)

0.25: 1

1: 4

The simplest formula of the substance: CH4

Molecular formula of the substance: M (CH4) / M (CxHyOz) = 16g / mol / 16g / mol = 1

Therefore, the molecular formula of the substance is CH4.