Use the combined gas law or ideal gas equation please

Question

There is a balloon that can hold 100.0 liters of air. If I blow up this balloon with 3.00 moles of oxygen gas at a pressure of 1.00 atmospheres, what is the temperature of the balloon? - Show Work

Answer 1

Assuming that oxygen behaves as an ideal gas and using the ideal gas equation: PxV=nxRxT

The temperature T will be calculated based on the equation:

T = (PxV/nxR) = 1.00 (atm)x100.0 (L)/[3.00 (mol)x0.0821 (L.atm/mol.K)]= 406.0 K = (406.0-273) ºC = 133 ºC