Find the molecular formula of the hydrocarbon, the mass fraction

Find the molecular formula of the hydrocarbon, the mass fraction of carbon in which is 83.3%. The relative vapor density of this substance for hydrogen is 36.

1. Find the molar mass of the hydrocarbon by the formula:

M = po * Ar, where M is molar mass, po is hydrogen density, Ar is atomic mass.

Substitute the values:

M (CxHy) = 36 * 2 = 72g / mol – hydrocarbon.

2. Find the mass of carbon:

m = ω * M, where m is the mass, ω is the mass fraction.

We substitute:

m = 0.833 * 72 = 60g

3. Find the mass of hydrogen:

m = 0.167 * 72 = 12g

4. The number of carbon atoms:

n = m / M

n = 60g / 12 g mol = 5 mol

5. The number of hydrogen atoms:

n = 12g / 1g mol = 12 mol

6. Quantitative ratios:
CxHy = C5H12

Answer: С5Н12