Question

The isotopic distribution of c12 and c14 is 98% and 2% respectively the number of carbon 12 atoms in 12 gram of carbon is

Answer 1

The isotopic distribution of C-12 and C-14 is 98% and 2% 

This statement means that in a sample of carbon

98% will be C-12

2% will be C-14

So, given 12 g of sample, C-12 will be 98% of this mass

Mass of C-12 = 98/100 X 12

                      = 11.76 g

Answer 2

Solution :

14 g of carbon 14 atom contains =6.023×1023atoms=6.023×1023atoms

1 g of carbon 14 atom contains =6.023×1023/14=6.023×1023/14

12 g of carbon 14 atom contains =(6.023×1023×12)/14=(6.023×1023×12)/14

=5.16×1023=5.16×1023

Now its 2%2% is (5.16×1023×2)/100(5.16×1023×2)/100

=10.32×1021=10.32×1021

So, the number of C−14C−14 atoms in 12 g of carbon is 10.32×1021