THE EMPIRICAL FORMULA (o-level chemistry)

THE EMPIRICAL FORMULA

The empirical formula of a compound is the simplest formula, which shows the ratio of the atoms present in a compound or a molecule by mass.

The molecular formula of a compound is the formula, which shows the number of each kind of atoms present in the compound.

TO CALCULATE THE EMPIRICAL FORMULAE

Example I

Sodium sulphate has the following composition by mass; sodium 32.4% sulphur 22.5% and oxygen 45.1%.

solution

Example 2

A compound contains oxygen and copper only.  The molecular mass is 159.0. 

What is its Empirical and molecular formula if the percentage of copper is 76

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Compiled by Dr. Bbosa Science