Empirical & Molecular Formula (AQA A-Level Chemistry): Flashcards

Simplest whole-number ratio of atoms of each element

Actual number of atoms of each element in a molecule

$CH_2O$

Molecular is whole-number multiple of empirical

$n = \frac{M_r \text{ (Molecular)}}{M_r \text{ (Empirical)}}$

Convert masses to moles using $\frac{\text{Mass}}{A_r}$

Divide each mole by smallest mole value

Adjust to whole numbers (multiply if needed)

Empirical formula and molar mass of compound

Molecular = (Empirical) × $n$