A compound with an empirical formula of CH3 has a molar mass of 60.2 g/mol. What is its molecular formula?

C₄H₁₂

Explanation:

The empirical formula gives you your smallest whole number ratio for the elements in the compound. Find the molar mass using a periodic table. We have one carbon (12.01 g/mol) and three hydrogens (1.008 g/mol). Therefore our molar mass for the empirical formula is 12.01 + 3(1.008) = 15.034 g/mol. To find the molecular formula divide the given molar mass by the empirical formula's molar mass 60.2/15.034 = 4.004257017 = 4. This number is the amount to multiply the empirical formula by to get the molecular formula, therefore your molecular formula is C₄H₁₂