Question

Calculate the atomic mass of potassium if the abundance atomic masses of the isotopes making up its naturally occurring samples are as given below:

Answer 1

After accounting for the given isotope abundances, the atomic mass of potassium is approximately 39.076 amu.

To solve this problem

Potassium-39 is isotope 1.

93.12% in abundance

Mass of an atom: 38.964 amu

Potassium-41 is isotope two.

Availability: 6.88%

Mass of an atom: 40.962 amu

Now let calculate the atomic mass of potassium:

Atomic mass = (0.9312 * 38.964) + (0.0688 * 40.962)

Atomic mass = 36.2637888 + 2.8124096

Atomic mass ≈ 39.076 amu

Therefore, After accounting for the given isotope abundances, the atomic mass of potassium is approximately 39.076 amu.

Answer 2

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:

`AtomicMassK=(38.964amu*93.12\%)/(100\%)+(40.962*6.88\%)/(100\%)`
`\begin{gathered} AtomicMassK=36.283amu+2.818amu \\ AtomicMassK=39.101amu \end{gathered}`

Answer: The molar mass of pottasium will be 39.101amu