There are many types of enthalpy changes, depending on the kind of process or reaction happening. Here are the main ones explained simply:
- Enthalpy of Reaction
- Heat change when a chemical reaction happens.
- Enthalpy of Formation
- Heat change when 1 mole of a compound is made from its elements in their natural states.
- Enthalpy of Combustion
- Heat released when 1 mole of a substance is burned completely in oxygen.
- Enthalpy of Neutralization
- Heat released when an acid reacts with a base to form water.
- Enthalpy of Solution
- Heat change when a substance dissolves in a solvent (can be positive or negative).
- Enthalpy of Fusion
- Heat needed to melt 1 mole of a solid into liquid at its melting point.
- Enthalpy of Vaporization
- Heat needed to boil 1 mole of liquid into gas at its boiling point.
- Enthalpy of Sublimation
- Heat needed to change 1 mole of solid directly into gas.
- Enthalpy of Atomization
- Heat needed to form separate atoms from an element in its natural state.
- Enthalpy of Hydrogenation
- Heat released when hydrogen is added to an unsaturated compound (like turning oils into fats).
In short: Different enthalpy changes describe heat absorbed or released in different processes like reactions, dissolving, melting, boiling, burning, or forming compounds.