Question

The empirical formula of a compound is C₂H₅, and its molecular weight is 58, then its molecular formula is __________.

Answer 1

• The empirical formula represents the simplest form of formula which expresses the relative numbers of atoms in the compound.
• The molecular formula denotes the actual number of atoms of different elements present.

Molecular formula = n× Empirical formula, where n=$\frac{\mathrm{Molecular}\mathrm{formula}\mathrm{weight}}{\mathrm{Empirical}\mathrm{formula}\mathrm{weight}}$

Given molecular weight = 58g

The empirical formula weight of C₂H₅= 2×12 +1×5=29 g

Therefore n = $\frac{58}{29}$=2 ,

Molecular formula = 2(C₂H₅)= C₄H₁₀

Hence, the empirical formula of a compound is C₂H₅, and its molecular weight is 58, then its molecular formula is C₄H₁₀.