What is the atomic mass of a hypothetical element that consists of the following
ID: 704272 • Letter: W
Question
What is the atomic mass of a hypothetical element that consists of the following isotopes in the indicated natural abundances?
Isotope Isotopic mass
(amu) Relative abundance
(%)
1 85.9 12.2
2 86.9 15.0
3 90.9 72.8
Express your answer to three significant figures and include the appropriate units.
B)
What is the atomic mass of the element that consists of the following isotopes in the indicated natural abundances?
Express your answer to three significant figures and include the appropriate units.
Isotope Isotopic mass(amu) Relative abundance
(%) 1 57.93 67.76 2 59.93 26.16 3 60.93 1.25 4 61.93 3.66 5 63.93 1.16
Explanation / Answer
Ans :
The atomic mass of an element is the average of sum of the masses of its isotopes , each multiplied by its relative abundance.
So here :
A)
M = [ (85.9 x 12.2) + (86.9 x 15.0) + (90.9 x 72.8) ] / 100
= 89.7 amu
B)
M = [ (57.93 x 67.76) + (59.93 x 26.16) + (60.93 x 1.25) + (61.93 x 3.66) + (63.93 x 1.16) ] / 100
= 58.7 amu