What does the empirical formula indicate?

May 19, 2014

Empirical formulas provide the lowest whole number ratio of elements present in a compound.

Formulas for ionic compounds are always empirical formulas.

Examples:
NaCl is a 1:1 ratio of sodium and chloride ions
$C a {F}_{2}$ is a 1:2 ratio of calcium and fluoride ions
$A {l}_{2} {O}_{3}$ is a 2:3 ratio of aluminum and oxide ions

Empirical fomulas also can be written for molecular compounds (covalent Bonding)

Examples:
Hydrogen peroxide (${H}_{2} {O}_{2}$) has an empirical formula of $H O$.
Glucose (${C}_{6} {H}_{12} {O}_{6}$) has an empirical formula of $C {H}_{2} O$.
Sucrose (${C}_{12} {H}_{22} {O}_{11}$) has the same empirical formula as its molecular formula

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

Simple explanation, nice looking website https://www.chem.wisc.edu/deptfiles/genchem/sstutorial/Text6/Tx65/tx65.html