An isotope corresponds to the variation of an element that has a different number of neutrons, that is, its mass number changes. To find the atomic mass, we take the average of the atomic mass of the isotopes multiplied by their abundance.
So the atomic weight of potassium, in this case, will be:
[tex]AtomicMassK=\frac{38.964amu\times93.12\%}{100\%}+\frac{40.962\times6.88\%}{100\%}[/tex][tex]\begin{gathered} AtomicMassK=36.283amu+2.818amu \\ AtomicMassK=39.101amu \end{gathered}[/tex]
Answer: The molar mass of pottasium will be 39.101amu
