Mass spectrometry can be used to identify the chloroauric acid. Naturally occurring chlorine
exists as two isotopes 35Cl (75% abundance) and 37Cl (25% abundance). 197Au is 100%
abundant.
(c) Calculate the m/z values and intensities of the molecular ion peaks for the AuCl4− ion as
a percentage of the total. Use integer masses in the calculation.
I understand how to calculate the m/z values however I am unsure how to calculate the molecular ion peaks, for example for a AuCl4-, the m/z value is 339 so don't you have to do 0.75 cubed times 0.25