This document discusses intermolecular forces (IMFs), the attractive forces between molecules that are weaker than intramolecular chemical bonds. It describes the main types of IMFs - London dispersion forces, dipole-dipole forces, and hydrogen bonding - and how their relative strengths depend on factors like molecular mass and polarity. IMFs determine key properties like a substance's boiling point, with stronger IMFs requiring more energy to overcome, resulting in higher boiling temperatures.

1. Intermolecular Forces

2. States of Matter Attraction between molecules increasing

3. Intermolecular Forces a.k.a. van der Waal’s Forces Attractive force between molecules Much weaker than chemical bonds within molecules

4. Types of Intermolecular Forces London Dispersion Forces: an attractive force acting between all molecules * attraction of electrons of one atom to nucleus of another atom * very weak force * increases in strength as molar mass increases (more electrons)

5. Dipole-Dipole Forces: attractive force acting between oppositely charged ends of polar molecules. * medium strength * strongest when molecules close together

6. Hydrogen Bonding: attractive force between positive hydrogen atom of one molecule and N, O or F in another molecule * strongest force * NOT a chemical bond

7. Predict IMF acting between molecules of: F 2 - London dispersion PH 3 - dipole-dipole, London dispersion CH 4 - London dispersion H 2 O - Hydrogen bonds, dipole-dipole, London dispersion

8. Properties of Liquids Boiling Point: Temperature at which a liquid becomes a gas * It represents the amount of energy to overcome the intermolecular forces holding the liquid molecules together * Substances with greater intermolecular forces have higher boiling points

9. Boiling point is higher for molecules with greater intermolecular forces