Thermochemistry-Calculating q, w, and ΔE.

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[xgiapet12x]

A balloon filled with 54.1 mol helium has a volume of 1212. L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 33.0°C as it expands to a volume of 1359. L, the pressure remaining constant. Calculate q, w, and ΔE in kJ for the helium in the balloon. (The molar heat capacity for helium gas is 20.8 J/°C·mol.)

I was able to figure out q:
q= n cp ΔT= (54.1)(20.8 )(33.0-0.0)=37134 J/1000=37.1 kJ

I know that in order to find ΔE you need to add q and w, but i don't know how to find w. Help?   
 
 
 

[kyle1990]

w=-P X change in volume

p is the pressure

[xgiapet12x]

w= (-1.00 atm)(1359 L - 1212 L)=-147

is this right?

[kyle1990]

yes