Check your answer...do you agree? Great if you do. If you do not check the Solution: below the table to see how the number of Mo atoms is calculated.

Formula

M , Molar Mass

(g­mol-1)

mass of sample

(g)

n, number of

moles of sample

N, number of atoms,

molecules or formula units

Mo

95.9

6.02 x 103

62.8

3.78 x 1025 atoms

Solution:

We are to calculate the number of atoms, molecules or formula units of Mo in the sample. First we need to know that we are calculating the number of atoms in this case. Molybdenum is a metallic element, and therefore, is best described as an atom at the atomic level. Since we know the moles of Mo in the sample we can determine the number of atoms using Avogadro's number,

Click here if you'd like to try another problem.