Question

Calculate the number of atoms in exactly 3.5 moles of naturally occurring calcium.

•21.1x1023 Ca atoms
•6.022x1023 Ca atoms
•1.807x1024 Ca atoms
•2.11x1024 Ca atoms

Answer 1

2.11x10^24 Ca atoms

In order to find the amount of atoms we must use Avogadro’s number, 6.022 x 10^23

Since we have moles, 3.5 the equation would look like this

3.5 moles Ca x 6.022x10^23/1 = 2.1077 x 10^24, which we round to 2.11 x 10^24 atoms of Ca