What is the molecular formula of a compound that has a formula mass of 50.48 amu and an empirical formula of ch3cl?

To find the molecular formula from the empirical formula, you need to find a multiple (x) that will give you the molar mass of the compound which in the question is 50.48 g/mol.

If CH₃Cl is the empirical formula
 molar mass of empirical formula = (12 × 1) + (1 × 3) + (35.5 × 1) g/mol
                                                     =  50.5 g/mol
let x = multiple
let molecular formula = Cₓ H₂ₓ

            multiple = molecular mass ÷ empirical mass
                         =  50.5 g/mol ÷  50.48 g/mol
                         ≈  1

If molecular formula = Cₓ H₃ₓ Cl

then molecular formula = C₍₁₎ H₃₍₁₎ Cl₍₁₎

                                      = CH₃Cl