Write the formula for the compound of carbon and hydrogen, the relative molecular weight

Write the formula for the compound of carbon and hydrogen, the relative molecular weight of which is equal to the relative atomic weight of oxygen.

Given:
Mr (CxHy) = Ar (O)

To find:
CxHy -?

Decision:
1) Using the periodic system of D.I.Mendeleev, determine the relative molecular weight of the hydrocarbon and the relative atomic weight of carbon:
Mr (CxHy) = Ar (O) = 16;
Ar (C) = 12;
2) The hydrocarbon contains only 1 carbon atom, otherwise Mr (CxHy)> Ar (O);
3) Mr (CHy) = Ar (C) * N (C) + Ar (H) * N (H);
16 = 12 * 1 + 1 * y;
y = 4;
4) Unknown substance – CH4 – methane;
5) CH4 + 2O2 => CO2 + 2H2O.

Answer: Unknown substance – CH4 – methane.