# Determine the formula of a substance consisting of carbon and hydrogen atoms

**Determine the formula of a substance consisting of carbon and hydrogen atoms, the vapor density of which for hydrogen is 8.**

Since the substance is composed of hydrogen and carbon, therefore, the general formula is as follows: CxHy.

Next, determine the molar mass of this substance, for this use the following formula:

M (CxHy) = 2 * D.

Where M is the molar mass of the substance;

D is the hydrogen density of the substance.

Further, in order to calculate the molar mass of a given substance, it is necessary to substitute known values in this formula. Write down the solution.

M (CxHy) = 2 * 8 = 16 g / mol.

Therefore, the molar mass of this substance is 16 g / mol.

M (CH4) = 12 + 4 * 1 = 16 g / mol.

This means that the formula of this substance is CH4, therefore, this substance is called methane.

Answer: CH4 methane.