The answer is boiling liquids I think
1.) 28.0 grams of oxygen
28 grams (1 mole/16 grams per mole)=1.75 moles oxygen
2.)5.0 moles of Iron
5 moles(55.845 grams/1 mole)=279.225 grams Iron
3.) 452 grams Argon
452 grams(1 mole/39.948 grams)=11.315 moles Argon
4.) 16.5 moles Hydrogen
16.5 moles(1.01 grams/1 mole)=16.665 grams Hydrogen