Question

On a mission to a newly discovered planet, an astronaut finds gallium abundances of 61.29% for 69Ga and 39.71% for 71Ga. What is the atomic mass of gallium for this location?. The mass of 69Ga is 68.7200amu. The mass of 71Ga is 70.9200amu.

Answer 1

(exact weight of isotope #1) (abundance of isotope #1) + (exact weight of isotope #2) (abundance of isotope #2) = average atomic weight of the element(68.72*61.29) + (39.71*70.92) = 4211.84 + 2816.237028.07/100= 70.28

70.28 is the atomic mass of Gallium for the location