AP Chemistry 3.1: Intermolecular forces

Intermolecular forces is part of Unit 3: Properties of Substances and Mixtures. The main skill is to compare forces between particles and predict effects on physical properties. Before answering, decide whether the prompt is asking for a particulate explanation, a mathematical setup, a graph interpretation, or a connection between more than one representation.

The first idea to keep straight is that london dispersion forces exist between all particles and increase with polarizability. In the same topic, remember that dipole-dipole forces occur between polar molecules. A complete AP answer also uses the fact that hydrogen bonding is a strong dipole interaction involving H bonded to N, O, or F. These ideas should be tied to specific particles, charges, attractions, energy changes, or measured quantities rather than stated as isolated facts.

For calculations or symbolic work, anchor the solution with stronger IMFs usually mean higher boiling point and lower vapor pressure. Define what each quantity represents, substitute values with units, and check whether the sign, magnitude, charge balance, atom balance, or equilibrium direction makes chemical sense for this topic.

Do not confuse intermolecular forces with covalent bonds within a molecule. In a free-response explanation, state the chemistry concept first, show the relevant equation or representation, and then explain how the evidence supports the conclusion for intermolecular forces.

How would you explain Intermolecular forces in one sentence?

Use the focus statement above, then add one particle-level or mathematical detail.

What evidence would support an AP-style answer on this topic?

Use a balanced equation, diagram, graph, table, numerical setup, or particulate model depending on the prompt.