Thermodynamics #2: Enthalpy

Enthalpy:

• Enthalpy (H): the total amount of kinetic and potential energy stored in a chemical system
• Change in enthalpy (ΔH): the change in enthalpy when a system undergoes a reaction
• Standard Enthalpy (ΔH°): the enthalpy change for a balanced chemical reaction
• Standard Enthalpy of Formation (ΔH°_f ): the enthalpy of a reaction when one mole of a particular substance is formed at SATP from its constituent elements at their standard states
• Enthalpy of combustion (ΔH°c ): the enthalpy for the combustion of one mole of a compound

When the enthalpy change for a reaction is greater than zero, the reaction is endothermic, for the system absorbs energy during the reaction. In contrast, when the enthalpy change for a reaction is less than zero, the reaction is exothermic.