Energetics (AS)

• Exothermic: release energy to surroundings.

  Endothermic: pulls energy in from the surroundings.

  
• Standard enthalpy change of combustion (ΔcH°): enthalpy change when one mole of substance is formed from its elements under standard conditions
• Enthalpy change (ΔH): amount of heat transferred between system and surroundings during reaction at constant pressure
• Standard enthalpy change of formation (ΔfH°): enthalpy change when one mole of compound reacts completely with oxygen under standard conditions, producing carbon dioxide and water only
• Heat lost/gained = mass of water x specific heat capacity x change in temperature
• Hess' Law: The total enthalpy change in a reaction is always the same and is independent of the route taken.
• A Hess' Cycle

  
• Enthalpy change of formation equation.

  
• Enthalpy change of combustion equation.