Question

5 number Q

​Q5. The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes 8 X¹⁶ and 8 X¹⁸ in the sample ?

Answer 1

$$\begin{gathered} letthepercentageofbeq\% \\ then \\ 16.2=16q+18\left(100-q\right) \\ 0.2q=1800-18q \\ 18.2q=1800 \\ q=\frac{1800}{18.2}=98.9percentavailabilityof16 \\ 1.1\%of18 \\ Regards \end{gathered}$$