Answer: Calculating an element’s atomic mass

The element silver (Ag) has an atomic mass of 107.868 amu. It has two isotopes—Ag-109 (108.905 amu) with an abundance of 48.1600% and Ag-107. Determine the amu for Ag-107.

Problem Strategy:

1. Set up an algebraic equation.

2. Solve for x, which is the amu for Ag-107.

Answer:

• Set up an algebraic equation.

(0.481600) 108.905 amu + x (0.518400) = 107.868 amu

• Solve for x, which is the amu for Ag-107.

52.4490 amu + 0.518400x = 107.868 amu

0.518400 x = 55.4180 amu

x = 106.905 amu