Why does the designed world change?

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?

What is the force of an object when it landed(sitting in the ground)

What is the pressure of 5.0 mol nitrogen gas in a 2.0 l container at 268 k (the universal gas constant is 0.0821 l•atm/mol•k) a. 55 atm b. 8.8 atm c. 0.018 atm d. 220 atm