Question

The first has a mass of 78.9 u and a percent natural abundance of 50.5 %. The second has a mass of 80.9 u and a percent natural abundance of 49.5 %. What is the atomic mass of the element?

Answer 1

Atomic mass of the element = 79.9 u

Step-by-step explanation:

Given:

Mass isotope 1 = 78.9 u

% abundance = 50.5%

Mass isotope 2 = 80.9 u

% abundance = 49.5%

To determine:

Atomic mass of the element

Calculation:

`Atomic\ mass = [Mass\ Isotope1* Abundance\ Isotope1+Mass\ Isotope2* Abundance\ Isotope2]\\\\Atomic\ mass = [78.9*0.505+80.9*0.495] = 79.9 u`