# Atmospheric pressure/Gas laws

1. Dec 12, 2006

### woox

1. The problem statement, all variables and given/known data
A balloon whose volume is 500 m^3 is to be filled with hydrogen at atmospheric pressure (1.01x10^5 Pa).
a. If the hydrogen is stored in cylinders of volume 2.5 m^3 at an absolute pressure of 35x10^5 Pa, how many cylinders are required? Assume temperature of hydrogen remains constant.
b.) What is the weight (in addition to weight of the gas) that can be supported by the balloon if the gas in the balloon and surrounding air are both at 0 degree C? The molecular mass of H2 is 2.02 g/mole. The density of air at 0 degree C and atmospheric pressure is 1.29 kg/m^3

c.( What weight could be supported If the balloon were filled with helium (with an atomic mass of 4 g/mole) instead of hydrogen, again at 0 degree C.

2. Relevant equations

PV=nRT?
V1T1=VfT2?

3. The attempt at a solution

I know I don't have any actual WORK for this problem, but that's because I have absolutely NO CLUE where to start. If anyone who is good at this kind of stuff, any help is appreciated. Thanks.

2. Dec 12, 2006

### Andrew Mason

What is the number of moles of hydrogen (H2) needed? I think you are supposed to assume a temperature of 0 degrees C (273 K). That should give you a start.

AM