Determine the number of cobalt atoms in a 117.86 g sample of cobalt

12.04 × 10²³ atoms

Explanation:

Given data:

Mass of cobalt = 117.86 g

Number of atoms = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

Number of moles of cobalt = 117.86 g/ 58.9 g/mol

Number of moles of cobalt = 2 mol

one moles of cobalt =  6.022 × 10²³ atoms of cobalt

2 moles × 6.022 × 10²³ atoms / 1 mol

12.04 × 10²³ atoms