Question

A steel cylinder has a volume of 25.0 L and is filled with N2 gas to a pressure of 200 atm. @ 30.0°C. How many moles of N2 gas does the cylinder contain? 

Answer 1

30.0^oC = 273.15 + 30.0 = 303.15 K

$n=\frac{PV}{RT}=\frac{200\ atm\times25.0\ L}{0.08206\frac{L\cdot{atm}}{mol\cdot{K}}\times303.15\ K}=201\ mol$

Answer: 201 mol