The composition of organic matter includes: C = 82.7%; H = 17.3%. Its vapor density in air is 2.

The composition of organic matter includes: C = 82.7%; H = 17.3%. Its vapor density in air is 2. What is the molecular formula of the substance?

We find the molar mass of organic matter:
M (CxHy) = D pv. * M pv .;
M (CxHy) = 2 * 29 = 58 (g / mol);
w (C) + w (H) = 100% – this means that only carbon and hydrogen are present in the formula.
Find the number of carbon and hydrogen atoms:
n (C) = (82.7 * 58) / (12 * 100) = 4;
n (H) = (17.3 * 58) / (1 * 100) = 10;
Formula: С4Н10 – butane, if the problem is solved correctly, then the molar mass of butane should be equal to the molar mass calculated in the problem. Check: 12 * 4 + 10 = 58 g / mol. Matches, then miscalculations are correct.
Answer: Bhutan – C4H10.