Which one has the greatest mass?

1. 3.55 mol O atoms

2. 4.52 g O atoms

3. 0.0032 kg O2 molec

4. 7.39 * 1023 O2 molec

To determine the one with the greatest mass, we convert all options into the same units of mass as follows:

1. 3.55 mol O atoms (16 g / mol) = 56.8 g O

2. 4.52 g O atoms

3. 0.0032 kg O2 molec (1000 g / 1kg) (1 mol / 32 g) (2 mol / 1 mol) (16 g / mol) = 3.2 g O

4. 7.39 * 10^23 O2 molec (1 mol / 6.022x10^23 molecules) (2 mol / 1 mol) (16 g/mol) = 39.27 g O