Asample 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 H32.0 grams of C →3212=2.66 moles of C8.0 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 CH3CH3.

Molar mass of CH3CH3 is 1⋅12+3⋅1.01=15.031⋅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 C2H6C2H6.