Question

a compound has an empirical formula of CH2 what is the molecular formula if it's molar mass is 252.5 grams/mol

Answer 1

Empirical formula is the simplest ratio of components making up the compound. the molecular formula is the actual ratio of components making up the compound.

the empirical formula is CH₂. We can find the mass of CH₂ one empirical unit and have to then find the number of empirical units in the molecular formula.

Mass of one empirical unit - CH₂ - 12 g/mol x 1 + 1 g/mol x 2 = 12 = 14 g

Molar mass of the compound is - 252 .5 g/mol

number of empirical units = molar mass / mass of empirical unit

                                           = $\frac{252.5 g/mol}{14 g}$

                                           = 18 units

Therefore molecular formula is - 18 times the empirical formula

molecular formula  - CH₂ x 18 = C₁₈H₃₆                                            

molecular formula is C₁₈H₃₆