Chemistry Kit

can someone help me with this chemistry question?

A domestic water-carbonating kit uses steel
cylinders of carbon dioxide, each with a vol-
ume of 250 mL. Each weighs 0.883 kg when
full and 0.666 kg when empty. What is the
pressure of gas in a full cylinder at 21 ?C?
Answer in units of bar.

mass of CO2 = 0.883 - 0.666 = 0.217 kg (217 g)
217 g / 44.0 g/mol = 4.93 mol CO2
P = nRT/V
P = 4.93 mol x 0.08206 x 294 K / 0.250 L = 476 atm
1 atm = 1.01325 bar
476 atm x 1.01325 = 482 bar