Question

The atomic weight of is 35.45 amu. There are only two naturally occurring isotopes of chlorine: , with a weight of 35.0 amu, and , with a weight of 37.0 amu. The natural abundance of the isotope is approximately:__________.

Answer 1

Answer:

The natural abundance of the 35.0 amu isotope is 77.5%, and the natural abundance  of the 37.0 amu is 22.5%

Explanation:

• The atomic weight of an element is the weighted average between each of the weight of isotopes.
• Then the natural abundance of 35.m amu isotope would be x, and for the other would be 1-x.
• According to the definition of the atomic weight for this case: $x*35+(1-x)*37=35.45$, then solving for x, it is obtain that the fraction for 35 amu isotope is 0.775 (77.5%), and for 37 uma isotope is 0.225 (22.5%).