Standard enthalpy change

• Standard conditions for determining enthalpy changes: Standard temperature is 298 Kelvin (25 degrees Celsius), standard pressure is 100 kilopascals, standard concentration is one mole per decimeter cubed for chemicals in solution, and all chemicals must be in their standard states (liquid, solid, or gas)
• Standard enthalpy change of combustion: Enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions and all chemicals are in their standard states
• Standard enthalpy change of formation: Enthalpy change when one mole of a compound is formed from its elements under standard conditions and all chemicals are in their standard states
• Enthalpy


  Heat energy in a chemical system
• Unit for standard enthalpy change is kilojoules per mole
• Standard enthalpy change of neutralization: Enthalpy change when one mole of water is formed in a neutralization reaction under standard conditions
• Standard enthalpy change of reaction: Enthalpy change when a reaction takes place in the molar quantities shown by the balanced chemical equation under standard conditions and all chemicals must be in their standard states
• Measuring enthalpy is extremely difficult, so instead, we determine enthalpy change