# What is meant by the term "equivalent mass"?

This is the mass of an element or compound that contains $\text{Avogadro's number}$ of formula units.......
The term $\text{equivalent mass}$ or $\text{equivalent weight}$ originally referred to the mass of element that would combine (in an integral ratio) with $1.008 \cdot g$ of hydrogen......
These days equivalent mass is taken as the molar mass, i.e. the mass of $6.022 \times {10}^{23}$ formula units......and these are now all conveniently listed on the Periodic Table.