Question

Chlorine consists of two isotopes with masses of 35 and 37. If the average atomic mass of a sample of chlorine atoms is 35.5, what is the 35Cl/37Cl ratio?4/13/12/11/1

Answer 1

The ratio 35Cl/37Cl = 3/1

Step-by-step explanation:

Step 1: Data given

Chlorine has 2 isotopes:

- mass = 35 g/mol

- mass = 37 g/mol

Average molar mass of chlorine = 35.5 grams

Step 2: Calculate the % of isotopes

35x + 37y = 35.5

x+y = 1 or x = 1-y

35(1-y) + 37y = 35.5

35-35y +37y = 35.5

0.5 = 2y

y = 0.25 = 37Cl

x = 1 - 0.25 = 0.75 = 35Cl

Step 3:

The ratio 35Cl/37Cl = 0.75/0.25 = 3/1