## hydrogen

If 277 L of LIQUID hydrogen has a mass of 19.7 kg, what volume will this amount of hydrogen occupy as a GAS at 25 degrees celcius and 1 atm?

Is there some kind of equation that I can use to make this problem easier?

THANKS!
 PV = nRT You'll use this equation for almost every gas problem. R (ideal-gas constant) = 0.0821 L-atm/mole-K V = volume (L) P = pressure (atm) n = amount (moles) T = temperature (K) V = nRT/P You need to convert the 19.7 kg H2 to moles H2 and the 25 C to Kelvin. If you need more help, go ahead and ask.
 Do you have to take into account the hydrogen beginning as a LIQUID and ending as a GAS?

## hydrogen

No because when you go from a liquid to a gas, the number of moles of H2 will still stay the same and therefore you can predict the volume.
 When converting 19.7 Kg to moles would you use H2 (being 2.0158g) or just H (being 1.0079g)?
 Good question. Always use the diatomic molecule...so H2.
 Thanks for your help. So if i have done things right my answer should be close to 2.39 X 10^5 L
 Yes I got a similiar answer. By the way, what value are you using for R? 0.0821 or something more precise?
 For this problem I just used 0.0821, but usually I use 0.082057