Question

Fe-54 = 5.845%

Fe-56 = 91.754%
Fe-58 = 2.119%
Calculate the average atomic mass/given their percent abundance

Answer 1

`\boxed {\boxed {\sf 55.76756 \ amu}}`

Step-by-step explanation:

The average atomic mass is the sum of the product of the given masses and their abundances. We have to complete two steps for each isotope, then add all the products together.

Fe-54

Convert the percent abundance to a decimal by dividing by 100.

• 5.845/100= 0.05845

Multiply the abundance as a decimal by the mass number. This is the number after the element in the isotope symbol (54 amu).

• 0.005845 * 54=3.1563 amu

Fe-56

Convert the percent to a decimal.

• 91.754/100=0.91754

Multiply the decimal by the mass number (56 amu).

• 0.91754 * 56= 51.38224 amu

Fe-58

Convert the percent to a decimal.

• 2.119/100=0.02119

Multiply by the mass number (58 amu).

• 0.02119 * 58 = 1.22902 amu

Average Atomic Mass

Add all the products together to find the average atomic mass.

• 3.1563 amu + 51.38224 amu + 1.22902 amu =55.76756 amu

The average atomic mass given the percent abundance is 55.7656 atomic mass units.