Learning Material Hess Law.docx

Calculation of enthalpy changes in a reaction from the enthalpy data of the related reaction is carried out using Hess's Law. Hess's law was put forward by a Swiss chemist Germain Henry Hess (1802-1805), which is based on the fact that enthalpy is a function of state. That is, changes in heat or heat of a reaction depend only on the initial state and the final state of the reaction. This law is very useful because in reality not all reactions can be determined by the reaction heat experimentally. According to Hess's Law, The reaction heat released or needed in a reaction does not depend on the reaction, but only depends on the initial and final state of the reaction. Hess's law can also be written as follows: The enthalpy change in a reaction remains the same, both taking place in one stage and several stages.

Kalor reaksi yang dibebaskan atau diperlukan pada suatu reaksi tidak bergantung pada jalannya reaksi, tetapi hanya bergantung pada keadaan awal dan akhir reaksi.