To answer this question, we'll convert moles oxygen to grams oxygen using molecular weight.
The key is to recognize that we're dealing with O₂, not an oxide (just O)

(4.59 moles O₂) / 1

 

(32.00 g O₂) / (1 mole O₂)

  = 146.88 g O₂


4.59 moles of oxygen gas = 146.88 g O₂