Question

Chlorine has 2 stable isotopes with masses of 35.0 amu (75.53%) and 37.0 amu (24.47%). Calculate the average atomic mass of Chlorine

Answer 1

m₁ = atomic mass of first isotope = 35.0 amu

p₁ = percentage of first isotope = 75.53% = 75.53/100 = 0.7553

m₂ = atomic mass of second isotope = 35.0 amu

p₂ = percentage of second isotope = 24.47% = 24.47/100 = 0.2447

m = average atomic of chlorine

average atomic of chlorine is given as

m = (m₁ p₁ + m₂ p₂)

inserting the above values in the equation

m = ((35.0) (0.7553) + (37) (0.2447))

m = 35.5 amu