Determine the number of atoms or molecules in each of the following substances. 1. 0.30 mol F 2. 0.70 mol iron 3. 4.0 mol Na 4. 4.0 mol NH3

Determine the number of atoms or molecules in each of the following substances.
1. 0.30 mol F 
2. 0.70 mol iron
3. 4.0 mol Na
4. 4.0 mol NH3


A mole is simply 6.02x10^23 atoms/molecules/particles/anything, so to figure out how many atoms are in each of those amounts of moles, you need only multiply the number of moles by 6.02x10^23, and then round to the appropriate number of sig figs.

1. .30 * 6.02x10^23 = 1.8x10^23 atoms F.
2. .70 * 6.02x10^23 = 4.2x10^23 atoms Fe.
3. 4.0 * 6.02x10^23 = 2.4x10^24 atoms Na
4. 4.0 * 6.02x10^23 = 2.4x10^24 molecules NH3

It's just like how a dozen is 12. To have a dozen of anything is to have 12 of anything. To have 4 dozen of anything is to have 48 of anything. That's why 4 moles of Na and 4 moles of NH3 come out to be the same number.