One mole of oxygen gas at STP is equal to ______

1. 6.022×1023 molecules of oxygen

2. 6.022×1023 atoms of oxygen

3. 16 g of oxygen

4. 32 g of oxygen

(a, d)
1 mole of O2 gas at STP=6.022×1023 molecules of O2 (Avogadro Number)=32g of O2. Hence, 1 mole of oxygen gas is equal to molecular weight of oxygen as well as Avogadro number.