Intermolecular forces & physical properties

Solubility

Polar solutes in polar solvents or non-polar solutes in non-polar solvents:

• If they can form complimentary intermolecular forces, they are easily able to form those intermolecular forces between one another.

• Little resistance of mixing between molecules.

Polar solutes in non-polar solvents/Non polar in solutes in polar solvents

• Polar solutes form stronger forces of attraction with each other than they do with the nonpolar molecules.

• Resulting in a resistance between the two.

Melting and boiling point

An increase in molecular size shows a general increase in melting and boiling points

• Hydrogen bonding >> Dipole-Dipole forces >> Dispersion forces

Vapour presssure

Measure of the tendency of a substance to evaporate (kPq)

To evaporate molecules must overcome the intermolecule forces keeing it in the liquid phase

• As strength of the intermolecular forces increases, vapour pressure decreases

• Weakest intermolecular forces have high vapour pressure

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