How much volume in liters will 100.0 g of oxygen occupy at 100 degrees celcius and 100 atm pressure?

Answer 1

100 C = 373 K and 100 g of O2 is 100/32 = 3.125 moles.

You could use the formula V = nRT/P directly (if you know R), or reason as follows:

At STP (0 C and 1 atm), that amount of O2 would occupy 3.125 moles x 22.4 (l/mole) = 70.0 liters

Finally, multiply that by (373/273)(1/100) to get the volume at 100 atm and 100 C