How to calculate average atomic mass?

To calculate the average atomic weight, each exact atomic weight is multiplied by its percent abundance (expressed as a decimal). Then, add the results together and round off to an appropriate number of significant figures. read more

How to Find Average Atomic Mass. Two Parts: Calculating Average Atomic Mass Using the Result Community Q&A. Average atomic mass is not a direct measurement of a single atom. Instead, it is the average mass per atom for a typical sample of a given element. read more

Average atomic mass of copper = (62.93 amu × 0.6909) + (64.94 amu × 0.3091)= 63.55 From the calculation, we know that an AVERAGE atom of copper has a mass of 63.55 amu. Notice that in this problem, we would predict that the average is closer to the weight of the lighter isotope. read more