Question

Determine the number of atoms in 98.3 g mercury, Hg

Answer 1

The answer is 2.95 × 10²³ atoms

Atomic mass is 200.59 g.
So, 1 mole has 200.59 g. Let's calculate how many moles have 98.3 g:
1M : 200.59g = x : 98.3g
x = 98.3 g * 1 M : 200.59 g = 0.49 M

To calculate this, we will use Avogadro's number which is the number of units (atoms, molecules) in 1 mole of substance:

6.023 × 10²³ atoms per 1 mole
How many atoms are in 0.49 mole:
6.023 × 10²³ atoms : 1M = x : 0.49M
x = 6.023 × 10²³ atoms : 1M * 0.49M = 2.95 × 10²³ atoms

Answer 2

1.22875 x 6.02 x 10^23=7.397075 x 10^23