Question

I don't really understand what vapor pressure is, could someone explain it to me? I'm trying to understand how impure substances have different melting and boiling points based upon vapor pressure.

Answer 1

vapour pressure is the pressure exerted by molecules in vapor ...which is dissociated from liquid phase or solid phase...basically when liquid molecules gain heat ...dissociation occurs within the molecule and the atom with higher energy flies off creating pressure in a container which we call as vapor pressure....now to dissociate molecules we need to provide heat in different amount because different substances have different bond strength so stronger bond will need more heat energy to be broken ..therefore different element have different vapor pressure ..and different melting point...

Answer 2

Nicely explained but dissociation is not the appropriate word to use there.Evaporation or vaporization is more appropriate.
Dissociation generally means the splitting of a compound to cations or anions in its solution.

Answer 3

i used dissociation to show how the molecules disintegrate and how do the particles with higher energy flies off therefore i used dissociation..also it can be used to show breaking of bonds..there are no constraints...