What are empirical formulas?

1 Answer

The empirical formula is the lowest term ratio of the atoms found in a molecule.

An example would be the empirical formula for a carbohydrate is
one carbon for two hydrogens for one oxygen

The carbohydrate glucose has a formula of
Notice that the ratio is 1 C to 2 H to 1 O.

For the alkane group of hydrocarbons the molecular formulas are

Ethane #C_2H_6#
Propane #C_3H_8#
Butane #C_4H_10#

In each of these molecules the molecular formula can be determines from a base formula of
This is the empirical formula for all alkanes.

Here is a video which discusses how to calculate an empirical formula.

video from: Noel Pauller

I hope this was helpful.