Answer:
3.32x10-6 moles occupy 2.0 10^18 molecules of water.
Explanation:
1 mol of anything occupies 6.02x10^23 (NA) particles.
Let's make a rule of three:
6.02x10^23 molecules are contained in 1 mol
2x10^18 occupy (2x10^18 / 6.02x10^23) = 3.32x10-6 moles
