SpudFiles

Hey guys,

I got a problem here. My freshman uni course is making us do a problem of modelling a combustion cannon for thermodynamics.

I can get the vapour pressure using Antoine's equation, but I can't google and find out whether the total pressure is the vapour pressure + atmospheric pressure or what.

Thanks!

Limbeh

vapour pressure of what?

They gave us 96% ethanol.

Googling around to find out the total vapour pressure is giving me nothing though.

I believe the atmosperic pressure is often disregarded, but if you really want to find out the total pressure, I think you just need to add 14.7 psi (im not sure what that is in other measurements) to your vapor pressure. its quite simple.

Open of closed container?

In an open container the pressure is just atmospheric, regardless of the presence of a volatile liquid.

In a closed container, and assuming it was closed before an appreciable amount of the liquid had vaporized, the pressure is atmospheric plus the vapor pressure of the liquid.