In the percent abundance equation, what does 'Average Mass' represent?

In the percent abundance equation, 'Average Mass' refers to the weighted average of the masses of an element's isotopes, taking into account the percent abundance of each isotope. This means that each isotope's contribution to the average mass is proportional to how abundant that isotope is in nature.

When calculating the average mass, one multiplies the mass of each isotope by its respective percent abundance (expressed as a fraction), then sums these products. As a result, this provides a more accurate representation of the mass of the element as found in a natural sample, rather than simply reporting the mass of the heaviest isotope or the total mass of all isotopes.

This method reflects the reality that elements often occur as a mixture of isotopes, and the average mass gives chemists essential information required for various calculations in both theoretical and applied chemistry.