Question

If a sample of pure sodium has a mass of 8.2 grams and sodium has an average atomic mass of 22.99 g/mol, how many sodium atoms are there in the sample?

Answer 1

8.2 grams X (1 mol/23 grams) X 6.02 X 10^23 atoms/mole = 2.15 X 10^23 atoms

Answer 2

There are
`2.148* 10^(23) atoms` of sodium.

Step-by-step explanation:

Mass of sodium = 8.2 g

Molar mass of sodium = 22.99 g/mol

Moles of sodium =
`(8.2 g)/(22.99 g/mol)=0.3567 mol`

1 mole =
`N_A=6.022* 10^(23) atoms`

Number of sodium atoms in 0.3567 moles = N

`N=0.3567* 6.022* 10^(23) atoms=2.148* 10^(23) atoms`