Whats the answer giving brainliest please help asap lol

Aroom with dimensions 7.00m×8.00m×2.50m is to be filled with pure oxygen at 22.0∘c and 1.00 atm. the molar mass of oxygen is 32.0 g/mol. how many moles noxygen of oxygen are required to fill the room? what is the mass moxygen of this oxygen?

Which of the four hypothetical substances you investigated would be most harmful to living organisms? 50 points!

If you are told to get 100 ml of stock solution to use to prepare smaller size sample for an experiment, which piece of glassware would you use?