How do I calculate the volume of a gas?

How to calculate gas volume needed?

• I’m trying to design a little inflatable tent. I’m thinking to use a little compressed air bottle such as soda stream gas bottle. I’ll have two gummy tubes of 5 cm diameter and about 2 meter long each. How much can a bottle like that inflate (by volume or pressure)? If such a bottle was equipped with a tire ventil for air refill what pressure can it take and would it inflate the same volume as the co2?

• Answer:

  I don't fully understand your setup, but you should be aware that bottled CO2 (as in the puncture-type bulbs) is at high pressure (~30 atm) and mainly it is liquefied, so the volume expansion factor is very large (much more than 30, probably a few hundred). You can't get such a ratio with air, because it doesn't liquefy at normal temperatures. If you fill a bottle with compressed air at say 10 atm, it will only expand by a factor of 10.