Carbon-12 is found in greater abundance than carbon-13 or carbon-14 Page 1 of 2 Abundance Equation. To calculate the average atomic weight each exact atomic weight is multiplied by its percent abundance expressed as a decimal. Calculating Average Atomic Mass 1.
The weighted average takes into account the mass and percentage abundance of each isotope.
12000000 09890 13003355 00110 12011 amu. First determine the fractional percent of each isotope in the substanceFor example chlorine has two major isotopes. Look up the mass of each isotope. To use this online calculator for Atomic.