U4 Section #1

Coefficient

A number indicating how many molecules or atoms are present in a chemical formula.

Subscript

A number written below and to the right of a chemical symbol, indicating the number of atoms of that element in a molecule.

H₂O

The chemical formula for water, representing two hydrogen atoms and one oxygen atom.

H₂O₂

The chemical formula for hydrogen peroxide, representing two hydrogen atoms and two oxygen atoms.

Difference between coefficients and subscripts

Coefficients indicate the number of molecules, while subscripts indicate the number of atoms of each element in a molecule.

2H₂O

Indicates two molecules of water, each containing two hydrogen atoms and one oxygen atom.

5H₂O

Indicates five molecules of water.