Question

The isotopic abundance of C-12 and C-14 is $98$% and $2$% respectively.What would be the number of C-14 isotope in $12$ g carbon sample?

• A. $1.03\times {10}^{22}$
• B. $3.01\times {10}^{23}$
• C. $5.88\times {10}^{23}$
• D. $6.02\times {10}^{23}$

Answer 1

The correct option is A $1.03\times {10}^{22}$

As abundance of C-14 is $2$%.
Mass of C-14 isotope in $12$ g sample =$\frac{2\times 12}{100}$
$\therefore$ No. of isotopes = no. of moles of C-14 $\times N=\frac{2\times 12\times N}{100\times 14}=1.03\times {10}^{23}$