The analysis of a compound gives the following percent composition by mass: C: 52.14 percent; H: 9.946 percent; S: 12.66 percent; O: 25.26 percent. What is its molecular formula given that its molar mass is 253.4 g?

C11H25SO4

Explanation:

The total mass of the compound is 253.4 g, so, the mass of each element will be:

C: 52.14% of 253.4 = 0.5214x253.4 = 132.12 g

H: 9.946% of 253.4 = 0.09946x253.4 = 25.20 g

S: 12.66% of 253.4 = 0.1266x253.4 = 32.08 g

O: 25.26% of 253.4 = 0.2526x253.4 = 64.00 g

The molar mass are: C = 12 g/mol, H 1 g/mol, S = 32 g/mol, and O = 16 g/mol

So, to know how much moles will be, just divide the mass calculated above for the molar mass:

C: 132.12/12 = 11 moles

H: 25.20 / 1 = 25 moles

S: 32.08/32 = 1 mol

O: 64.00/16 = 4 moles

So the molecular formula is C11H25SO4