desperate for physics help! please help me :(?

Question

We're doing stuff with the Ideal Gas Law and I've looked throughout our chapter and our notes and haven't found a problem similar to this. There are so many things missing! Argh. Oh and we also have gone over Thermal Expansion equations if that helps any. Here is the question:

A tank having a volume of 0.100 m3 contains helium gas at 120 atm. How many balloons can the tank blow up if each filled balloon is a sphere 0.300 m in diameter at an absolute pressure of 1.25 atm?

Thanks a bunch!

Answer 1

p1v1=np2v2
v2 = 4/3 pi 0.15^3 = 0.014137
n----> no. of balloons
putting values we get n = 679.03 so approx 679 balloons.
hope this helps

Answer 2

This one is quite easy if you look at it from the proper point of view. The only equation you need is PV =P'V', and you have the original pressure and volume, the final pressure (but not the volume), so do the obvious arithmetic and divide the result by the volume of one balloon to get the number that can be filled. You do need an equation for the volume of a sphere, but you should be able to find that easily enough if you don't already know it.

Answer 3

P1V1 = nP2V2
V2 = (4/3)π(0.15)^3 = 0.014137 m^3
n = [120*0.1/(1.25*0.014137)]
n = [679.06]
n = 679