Output the formula for a hydrocarbon containing 81.8% carbon if its relative density with respect to hydrogen is 22.

The molecular weight of hydrogen is 2 g / mol. Let’s find the molecular weight of the unknown hydrocarbon:
22 * 2 = 44 g / mol;

Let’s find the molecular weight of carbon in the compound:
44 * 0.818 = 36 g / mol;

The relative atomic mass of carbon is 12. Find the number of carbon atoms:
36/12 = 3 atoms;

Let’s find the molecular weight of hydrogen in the compound:
44 – 36 = 8 g / mol; (since the relative atomic mass of hydrogen is 1, the hydrocarbon contains 8 hydrogen atoms)

Answer: The hydrocarbon formula is C3H8.