termoquímica

Termoquímica is a branch of physical chemistry that studies the relationship between heat and other forms of energy in chemical reactions and physical changes. It focuses on the energy transformations that occur during these processes. Key concepts in thermochemistry include enthalpy, entropy, and Gibbs free energy. Enthalpy (H) is a measure of the total heat content of a system. Changes in enthalpy (ΔH) indicate whether a reaction releases heat (exothermic, ΔH < 0) or absorbs heat (endothermic, ΔH > 0). Entropy (S) is a measure of the disorder or randomness in a system, and its change (ΔS) influences the spontaneity of a process. Gibbs free energy (G) combines enthalpy and entropy (G = H - TS) to predict the spontaneity of a process under constant temperature and pressure.

The first law of thermodynamics, the law of conservation of energy, is fundamental to thermochemistry, stating that energy cannot be created or destroyed, only transformed. Hess's Law is another important principle, which states that the total enthalpy change for a reaction is independent of the pathway taken, allowing enthalpy changes for complex reactions to be calculated from simpler ones. Thermochemical data, such as standard enthalpies of formation and combustion, are tabulated and used in calculations to predict energy changes in various chemical and physical processes, which has broad applications in fields like chemical engineering, materials science, and environmental science.