Rates, energy and equilibrium

This topic collects the AP Chemistry ideas that decide how fast a reaction goes, where it ends up and whether it happens at all. It starts with kinetics. Reaction orders come from experimental data, not from the coefficients in the balanced equation, so you compare trials where only one concentration changes. Next comes the sign of ΔH. It is written from the system's point of view: heat leaving makes ΔH negative, which is exothermic, and the surroundings warm up. The third page covers equilibrium expressions. You write products over reactants raised to their coefficients, but you leave out solids and pure liquids. The last page is Gibbs free energy. A reaction is spontaneous when ΔG is negative, and because ΔG = ΔH − TΔS, being exothermic alone isn't enough. Entropy and temperature matter too. Work through the pages in order and write the sign of every quantity before you calculate. Most lost marks in this unit come from a single sign.