Determine the molecular formula of carbon containing 85.71% carbon atoms and 14.29% hydrogen.

univerkov | January 28, 2021 | education

Determine the molecular formula of carbon containing 85.71% carbon atoms and 14.29% hydrogen. The relative hydrogen density of a vapor-hydrocarbon is 35.

For the solution, let’s write down the data:
CxNu – hydrocarbon;

W (C) = 85.71%

W (H) = 14.29%

D (H2) = 35;

M (H2) = 2 g / mol;

Determine the formula CxNy -?

M (CxHy) = D (H2) * M (H2) = 2 * 53 = 70 g / mol.
Let’s determine the amount of carbon, hydrogen:
Y (C) = 85.71 / 12 = 7.14;

Y (H) = 14.29 / 1 = 14.29;

C: H = X: Y = 7.14: 14.29 = 1: 2;

The simplest formula is CH2

4. Let’s establish the formula based on the general:

CnH2n = 70;

14n = 70;

n = 5

C5H10 – Pentene.

Checking: M (C5H10) = 12 * 5 +10 = 70 g / mol.

Answer: Formula C5H10 (pentene).