The mass of a single molybdenum atom is 1.59*10-22 grams. How many molybdenum atoms would there be in 40.6 milligrams of molybdenum?

2.55*10²⁰ atoms of Mo are contained in 40.6 mg

Explanation:

1 atom of Mo has a mass of 1.59*10⁻²² g

So let's think a rule of three for this question.

Firstly, we convert the mass in mg to g

40.6 mg / 1000 = 0.0406 g

In the mass of 1.59*10⁻²² g, there is 1 atom of Mo

In the mass of 0.0406 g there are (0.0406 / 1.59*10⁻²²) = 2.55*10²⁰ atoms