Pressure due to boiling a liquid

1. Oct 18, 2009

sc298

I am looking for an equation to determine the pressure produced by boiling a liquid.
(On the net I can only find information on the effect that pressure has on boiling point)

for example, the pressure produced by heating liquid nitrogen to 0K.

Any help would be great!

Thank you

2. Oct 18, 2009

Staff: Mentor

"Boiling" means to heat a liquid to where the partial pressure of the gas is above ambient pressure. So if you confine a liquid and heat it, the pressure produced corresponds to the partial pressure or saturated vapor pressure at that temperature. You find this from a table, ie a steam table or similar. There are some on the web and any good thermo book will have a bunch of tables for different fluids in it.

Tables for Nitrogen might not go up that high - the pressures would be huge as that is well above the critical point for nitrogen (the point at which you can no longer distinguish liquid from gas - you can no longer define "boiling").

3. Oct 19, 2009

Phrak

You wouldn't heat Nitrogen to zero Kelvin. You would cool it.

Zero Kelvin is really cold.

4. Oct 19, 2009

Staff: Mentor

Lol, sorry - I saw 0K and thought 0C.

5. Oct 19, 2009

Phrak

You could talk to Redbelly about my blunder converting between Celcius and Kelvin. It went on for several posts

6. Oct 19, 2009

sc298

I meant heat Liquid Nitrogen to 0C (273K)

7. Oct 20, 2009

Phrak

Look up the phase diagram of N2. Pick the coordinate were the temperature is 273K. Where this line crosses the liquid-gas transition is the pressure you are interested in.

It looks like about 500 psi to me.

Last edited: Oct 20, 2009
8. Oct 20, 2009

Staff: Mentor

Do you have a link to a phase diagram? I couldn't find one.

9. Oct 20, 2009

sc298

Hero!

Many thanks!

10. Oct 20, 2009

Phrak

I googled images for N2 phase diagram. I only found a crude one.