What are empirical formulas?

1 Answer
Jun 14, 2014

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
$C {H}_{2} O$
one carbon for two hydrogens for one oxygen

The carbohydrate glucose has a formula of
${C}_{6} {H}_{12} {O}_{6}$
Notice that the ratio is 1 C to 2 H to 1 O.

For the alkane group of hydrocarbons the molecular formulas are

Ethane ${C}_{2} {H}_{6}$
Propane ${C}_{3} {H}_{8}$
Butane ${C}_{4} {H}_{10}$

In each of these molecules the molecular formula can be determines from a base formula of
${C}_{n} {H}_{2 n + 2}$
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.
SMARTERTEACHER