Germain Henri Hess
Germain Henri Hess | |
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Hess' law, Thermochemistry | |
| Scientific career | |
| Fields | Chemistry |
| Institutions | St. Petersburg Academy of Sciences |
Germain Henri Hess (
Early life and education
Hess was born on 7 August 1802 in
Contributions to chemistry
In 1830, Hess took up chemistry full-time, researching and teaching, and later became an adjunct professor of Chemistry at the
Like most of his colleagues, Hess was primarily an experimental chemist interested in the discovery and analysis of new substances. However, he also developed a strong interest for theoretical investigations. In particular, he wondered how chemical affinity relates to heat in chemical reactions. His experiments on various hydrates of sulfuric acid showed that the heat released when they formed was always the same, whether the reactions proceeded directly or through intermediates (1840). Hess thus formulated a special case of the conservation of energy two years before Julius Robert von Mayer stated a more general principle, in 1842.[2] Hess was fully aware of the importance of his own contribution.
In 1842, Hess proposed the law of thermoneutrality, which states that no heat is evolved in the exchange reactions of neutral salts in aqueous solution. A full explanation would only be given 45 years later, in terms of electrolytic dissociation, by the Swedish chemist Svante Arrhenius.[2]
After these two major discoveries, Hess was influential in the development of chemistry in Russia. His book Osnovania Chistoy Khimii (Fundamentals of Pure Chemistry) went through seven editions and remained the standard Russian textbook for undergraduate chemistry until 1861. Hess was active as a teacher and mentor of young scientists, until his poor health forced him to retire, in 1848.[2]
Later research and final days
Hess' investigation of minerals included the analysis of
Hess died prematurely in 1850, at the age of 48, in
Further reading
- Köhler-Krützfeldt, Angela; Christmann, Klaus (2000). "Dem Begründer der Thermochemie Hermann Heinrich Hess zum 150. Todestag". Chemkon. 7 (4): 193. .
- "Hermann Heinrich Hess" (PDF) (in German). Archived from the original (PDF) on 2012-03-08. Retrieved 2010-06-24.
References
- ^ S2CID 195242226.
- ^ .
- ^ Hess, Germain Henri (1840-01-01). "Recherches sur les quantités de chaleur dégagées dans les combinaisons chimiques". Comptes Rendus de l'Académie des Sciences. 10: 759–763.
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