Thermochemistry

Thermochemistry is the chemistry of heat and heat-associated chemical phenomena. It is concerned with heat exchange accompanying transformations like chemical reactions

A reaction in which heat is absorbed

reactants + energy as heat ------> products

• A reaction in which heat is evolved
• reactants -----> products + energy as heat

Endothermic

Exothermic

Enthalpy is the heat content of reacting materials. Enthalpy symbol, H

Delta H is the change in heat content of materials during a reaction. It is usually seen as a change in temperature.

Standard Enthalpy Change for a reaction is the heat change measured at a standard pressure and temperature (1.01x10⁵ Pa, 298K). All substances are in their normal physical state. Any solutions involved have a concentration of 1.0M

Standard heat of reaction is the amount of heat absorbed or evolved when the molar quantities of reactants as stated in the stoichiometric equation react together under standard conditions