Determination of heat of formation water. P3021501
You can get the concept of: The first law of thermodynamics, calorimetry, enthalpy of chemical reaction.
Principle: Standard molar enthalpy of chemical reaction is defined as the heat released in the formation of one mole of a pure substance from stable pure elements under constant pressure. For the reaction of hydrogen and oxygen leads to the formation of H2O, using calorimetric methods, determined the enthalpy of formation.