physical science

Question

Two short-lived isotopes of an element are produced in a nuclear reaction. One of these isotopes has a mass of 5.3731 amu and accounts for 75.5% of the production. The remaining other isotope has a mass of 7.3904 amu. Use this information to calculate the atomic mass of the element.

Answer 1

Hi Valerie,

 

We need to take a "weighted" average of the two isotopes to determine the atomic mass of the element.

 

Isotope     AMU       relative abundance

     1         5.3731         75.5%

     2         7.3904         24.5%

 

 

(5.3731 x .755) + (7.3904 x .245) = 4.0567 + 1.8106 = 5.8673

 

The atomic mass of the element is 5.8673