Answer:
55.768
Step-by-step explanation:
The following information is given in this question:
Fe-54 = 5.845%
Fe-56 = 91.754%
Fe-58 = 2.119%
First, we convert from percentage abundance to decimal abundance
Fe-54 = 5.845% = 0.05845
Fe-56 = 91.754% = 0.91754
Fe-58 = 2.119% = 0.02119
To find the average atomic mass of iron (Fe), we multiply each isotopes' decimal abundance by its mass no and find the sum as follows:
Average atomic mass = (0.05845 × 54) + (0.91754 × 56) + (0.02119 × 58)
Average atomic mass = 3.1563 + 51.38224 + 1.22902
Average atomic mass = 55.768