# The mass fractions of carbon and chlorine in a molecule of a substance are, respectively

The mass fractions of carbon and chlorine in a molecule of a substance are, respectively, 10.1% and 89.9%. Relative air density 8.173. The formula of the substance?

For the solution, let’s write down the data:
W (C) = 10.2%

W (Cl) = 89.9%

D (air) = 8.173

Determine: CxCly

Calculations: M (CxClу) = D (air) * M (air) = 8.173 * 29 = 237 g / mol.
Let’s determine the amount of carbon, chlorine:
Y (C) = 10.1 / 12 = 0.84;

Y (Cl) = 89.9 / 35.5 = 2.53 mol;

С: Сl = X: Y = 0.84: 2.53 = 1: 3

Simplest formula: CCl3

Let’s set the formula:
С2Сl6 – hexachloroethane.

M (C2Cl6) = 12 * 2 + 35.5 * 6 = 237 g / mol.

Answer: the formula of the substance is C2Cl6 (hexachloroethane). One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.