A sample of a compound contains 32.0g C and 8.0g H. It's molar mass is 30.0/mol. What is the compounds molecular formula?

Given mass of C is 32.0 grams

Given mass of H is 8.0 grams

Molar mass of C is 1212 g/mol

Molar mass of H is 1.01 g/mol

Thus

32.0 grams of C 8.0 grams of H → 3212 = 2.66 moles of C → 81.01 = 7.92 moles of H 32.0 grams of C → 3212 = 2.66 moles of C 8.0 grams of H → 81.01 = 7.92 moles of H

When we divide 7.92 by 2.66 we obtain 2.977 which is approximately 3. This means that the ratio of atoms of CC to the atoms of HH is 1:3.

Thus, empirical formula for the compound is C H3 C H3.

Molar mass of C H3 C H3 is 1⋅12+3⋅1.01=15.03 1⋅12+3⋅1.01=15.03. Since molar mass of the compound we have to find is 3030 g/mol we have tu multiply subscripts by 2.

Thus, final compound is C2 H6 C2 H6.