Question

in sample of elemental bromine, 55% or the atoms are Br-79, and the remainder are Br-81. if this sample is typical of naturally occurring bromine, what is the average atomic mass of bromine?

Answer 1

The average atomic mass of bromine is 79.9 amu.

Step-by-step explanation:

Given data:

Percentage of Br⁷⁹ = 55%

Percentage of Br⁸¹ = 45%

Average atomic mass of bromine = ?

Formula:

Average atomic mass = [mass of isotope× its abundance] + [mass of isotope× its abundance] +...[ ] / 100

Now we will put the values in formula.

Average atomic mass = [55 × 79] + [81 ×45] / 100

Average atomic mass = 4345 + 3645 / 100

Average atomic mass = 7990 / 100

Average atomic mass = 79.9 amu

The average atomic mass of bromine is 79.9 amu.