Answer:
55.56 amu
Explanation:
Let A, B, C and D represent the four isotopes of iron.
The following data were obtained from the question:
Isotope A (Fe-54):
Mass of A = 53.940 amu
Abundance (A%) = 5.82%
Isotope B (Fe-56):
Mass of B = 55.935 amu
Abundance (B%) = 91.66%
Isotope C (Fe-57):
Mass of C = 56.935 amu
Abundance (C%) = 2.19%
Isotope D (Fe-58):
Mass of D = 57.933 amu
Abundance (D%) = 0.33%
Average atomic mass =.?
The average atomic mass of the iron can obtained as follow:
Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100] + [(mass of D × D%)/100]
Average atomic mass = [(53.940 × 5.82)/100] + [(55.935 × 91.66 )/100] + [(56.935 × 2.19)/100] + [(57.933 × 0.33)/100]
= 2.848 + 51.270 + 1.247 + 0.191
= 55.56 amu
Therefore, the average atomic mass of the iron is 55.56 amu