This document provides an overview of key concepts in thermochemistry, including:
1) Kinetic and potential energy, and how temperature relates to the average kinetic energy of molecules. Heat is energy transferred between objects of different temperature.
2) The first law of thermodynamics states that the change in energy of a system equals the heat added plus work done. Enthalpy (H) accounts for heat and pressure-volume work.
3) Hess's law allows determining the enthalpy change of a reaction by summing the enthalpy changes of intermediate steps. Standard enthalpies of formation (ΔH°f) quantify energy released when compounds form from elements.
