A gaseous system undergoes a change in temperature and volume. What is the entropy change for a particle in this system if the final number of microstates is 0.711 times that of the initial number of microstates

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?