Ballons and Volumes!

Question

On a warm day, an amusement park balloon is filled with 47.8 g He. The temperature is 33˚C and the pressure in the balloon is 2.25 atm. Calculate the volume of the balloon.

Answer 1

find moles using molar mass of Helium:

47.8 grams He @ 4.0026 g/mol = 11.942 moles He

find volume, using

PV=nRT

(2.25 atm) (V) = 11.942 moles (0.08206 L-atm/mol-K) (310K)

V= 135.02 litres

Your answer (3 sig figs): 135 litres