How to destermine the isotope

See the explanation below, please.

Explanation:

Isotopes correspond to atoms with the same atomic number (Z) but different mass numbers (A), that is, they differ in the number of neutrons. Ex Carbon 14 and Carbon 12, Hydrogen and Deuterium.

Isotopes can be determined using the mass spectrometry technique, measuring the relative abundance of each ion (gives us the m / z, ratio between mass and charge).

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error