Question

If chlorine atom is available in the form of two isotopes Cl-35(75%) and Cl-37(25%), calculate the average atomic mass of chlorine atom.

Answer 1

average atomic mass

= [37 ( 75/100) + 37(25/100)]/2

= 35.5 amu

Answer 2

Given: Chlorine atom is available in the form of two isotopes Cl-35(75%) and Cl-37(25%).

To find: We have to find the average atomic mass of the chlorine atom.

Solution:

chlorine atom is available in the form of two isotopes Cl-35(75%) and Cl-37(25%).

Thus Cl-35 is present as 75% so, the amount of Cl is 35×75/100=26.25

Thus Cl-37 is present as 25% so, the amount of Cl is 37×25/100=9.25.

The average atomic mass of a chlorine atom is given as follows-

$\frac{26.25 + 9.25}{0.75 + 0.25} \\ = \frac{35.5}{1} \\ = 35.5$

The average atomic mass of a chlorine atom is 35.5 units.