chemistry degree level

hey guys

how does vapour pressure vary with temperature and discuss this in terms of intermolecular forces?

is it as one increases the other does aswell. im not sure how to explain it though help me please

Reply 1

Celifein

Have you tried consulting your textbooks/online resources/tutor? Alternatively, you could post this in the correct forum.

Edit: Should probably point out this thread isn't where it was when I commented.

Reply 2

vVPiKaVv

I'm not really confident about answering this..but I'll try..

When temperature is increased, the gaseous molecules gain kinetic energy. The intermolecular forces will be made weaker because the molecules now have enough energy to overcome the intermolecular forces present. As a result, the molecules are less attracted to one another, and there will be an increase in the collisions between the gaseous molecules and the internal surface of the container. This will then cause an increase in pressure..

I think I'm missing out some details..or maybe I'm wrong..could someone else verify my answer? Thanks.

Reply 3

user-name

I'm probably wrong, but as Temperature increases doesn't a gas expand, so the pressure decreases. In molecular terms i'd say the increase in temperature increases kinetic energy of the molecules so intermolecular forces are weakened.

Reply 4

ChemistBoy

Erm, vapour pressure is the pressure of the vapour in equilibrium with its non-vapour phases (either solid or liquid), so, in effect, you are discussing the tendancy for things to evaporate from a non-vapour phase. So with that in mind then you need to consider the inter-molecular forces in the liquid or solid state. I presume that you are considering a general trend with temperature so you can ask the simple question: what happens when I put more energy into the system, are molecules more likely or less likely to evaporate. The actual relationship is more complex than a simple linear relationship and you may or may not have covered it in thermodynamics yet.