Question

What is the average atomic mass of a sample that has two isotopes, one with a mass of 21 amu at 62% abundance and another with a mass of 22 amu at 38% abundance?

amu (atom weight)
please explian

Answer 1

Average atomic mass = 21.38 amu.

Step-by-step explanation:

Given data:

Mass of first isotope = 21 amu

Abundance of first isotope = 62%

Mass of second isotope = 22 amu

Abundance of second isotope = 38%

Average atomic mass = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100

Average atomic mass = (62×21)+(38×22) /100

Average atomic mass = 1302 +836 / 100

Average atomic mass = 2138 / 100

Average atomic mass = 21.38 amu.