The two isotopes of potassium with significant abundance in nature are 39K (isotopic mass 38.9637 amu, 93.258%) and 41K (isotopic mass 40.9618 amu, 6.730%). Fluorine has only one naturally occurring isotope, 19F (isotopic mass 18.9984 amu). Calculate the formula mass of potassium fluoride.

Solution 96P

Here, we have to calculate the formula mass of potassium fluoride.

Step 1 of 3

The given two isotopes are and

Let’s calculate the proton atomic mass from two isotopes.

For

Given

Isotopic mass = 38.9637 amu

Abundance = 93.258%

Calculate the fraction value = = 0.93258.

Proton of atomic mass from = Isotopic mass x Abundance

= 38.9637 x 0.93258

= 36.337 amu

Therefore, Proton of atomic mass from is 36.337 amu.

For

Given

Isotopic mass = 40.9618 amu

Abundance = 6.730%

Calculate the fraction value = = 0.06730

Poton of atomic from = Isotopic mass x Abundance

= 40.9618 x 0.06730

= 2.757 amu.

Therefore, proton of atomic mass from is 2.757 amu.

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