Question

How many C-13 atoms are present, on average, in a 1.6000×104-atom sample of carbon?

Answer 1

Answer;

= 171 atoms of C-13

Explanation;

• Carbon has two naturally occurring isotopes: C-12, whose natural abundance is 98.93% and C-13  whose natural abundance is 1.07%.
• Therefore, the number of C-13 atoms sample of 1.6000×10^4 atoms of carbon will be;

          = (1.6000×10^4 × 1.07 %)/100%

           = 171.2

           ≈ 171  atoms

Answer 2

I don't know why I am answering this question but assuming C-13 has a natural abundance of 1.07%:

(1.6000x10^4)(0.0107) = 171.2 = 171 atoms of C-13