Question

Chlorine has two stable isotopes with masses 34.97 amu and 36.97 amu. What is the percentage (%) of abundance of the isotope 34.97 amu? The average atomic weight of chlorine is 35.453 amu. (Use percentage and 2 decimals.)

Answer 1

The percentage of of abundance of the isotope 34.97 amu is 76.00%.

Step-by-step explanation:

To calculate the percentage of abundance of the isotope 34.97 amu, it is necessary to write an equation, assuming that the isotope with mass 34.97 is called Cl-35 and that isotope with mass 36.97 is called Cl-37. We can represent them like:

- Cl-35: x

- Cl-37: 1-x

Each isotope multiplied by its percentage and added will be equal to the average atomic weight of chlorine (35.452), so the equation is:

`\begin{gathered} 34.97*x+36.97*(1-x)=35.452 \\ x=0.76 \end{gathered}`

After solving the equation, we find that x=0.76, so the percentage of Cl-35 is 76.00% and the percentage of Cl-37 is 24.00% (1-0.76=0.24).