[header] How to calculate normality [title] Gather information about the equivalent weight of the reacting substance. [step] Consult chemical reference books to find out the valence and the molecular weight of the substance. Molecular weight is the ratio of the mass of 1 molecule of the substance to the mass (one carbon12 molecule divided by 12. 
) valence is determined by the maximum number of subatomic valence or atom to atom bonds that the substance may form with other substances. This information will be required to determine normality.