What is an empirical formula?

2 Answers
Jan 26, 2017

Answer:

It's a ratio formula of all the elements in the compound.

Explanation:

A ratio formula doesn't say anything about the actual numbers of atoms and how they are interconnected.

Example:
By burning a carbon-hydrogen compound and measuring the water and #CO_2# we get the empirical formula #CH_2#.

This means the compound has a molecular formula of #C_nH_(2n)#, or amounts of #C# and #H# atoms in the ratio 1:2.
So it could be #C_2H_4# (ethene), #C_3H_6# (propene), any other "-ene", or a lot of others (like cyclo-hexane).

Determining the molecular mass (step two) may lead to a molecular formula, which tells us the right number of atoms in the molecule, but still nothing about how they are connected.

Jan 26, 2017

Answer:

The smallest whole number ratio of each element in one atom of a compound.

Explanation:

For example the Empirical formula of Butane (#C_4H_10#) is #C_2H_5#.