2 A naturally occurring sample of argon contains 2696 atoms

2. A naturally occurring sample of argon contains 2696 atoms of Ar,504 atoms of 38Ar, and 7968 × 10s atoms of 40Ar, what is the percent abundance of the most abundant isotope? (a) 99.60% (b) 95.08% (c) 7135% (d) 99.92%

Solution

most abundant isotope is Ar⁴⁰

percentage of abundance =(no of atoms of Ar⁴⁰/total no of atoms)*100

{(7.968*10⁵)/(7.968*10⁵+2696+504)}*100 =99.6 %