A chemical formula is a way of presenting information about the chemical proportions of elements that constitute a particular molecule. This is done by using a set of short hand symbols to represent the type of element, as well as numbers and the plus and minus signs.

The letters indicate the type of element (ie. is hydrogen and is nitrogen), the subscripts indicate the quantity of each element (if the number is omitted it means that there is only 1), and the superscript indicates the charge of the ion if any.

Types

Empirical Formula

An empirical formula is the simplest whole number ratio of elements present in a molecule. In some cases (ie. ) the empirical formula is the same as the molecular formula. Additionally some molecules have identical empirical formulas (ie. formaldehyde and acetic acid ).

Examples

• - Water
• - Nitrate

Molecular Formula

The molecular formula represents the exact quantity of each of the elements in a given particular molecule. For example the molecular formula for glucose is but the empirical formula is . A molecular formula provides more information about a molecule than its empirical formula, but is more difficult to establish.

Examples

• - Glucose
• - Acetic Acid