given that the mean relating atomic mass of chlorine gas is 35.5 and contains a mixture of two isotopes of mass number 35 and 37 . Calculate the ratio of each isotope in the naturally occurring element

The abundance of isotope 35 = 75%

The abundance of isotope 37 = 25%

Ratio isotope 35 :  isotope 37 = 3 : 1

Given

Ar Cl = 35.5

Two isotopes of mass number 35 and 37

Required

The ratio of each isotope

Solution

If the abundance of isotope 35 is x%, then the abundance of isotope 37 is (100-x)%

35.5 = x%.35 + (100-x)%.37

35.5 = 0.35x+0.37(100-x)

35.5=0.35x-0.37x+37

0.02x=1.5

x=75