Chemical Reactions Chemical reactions are the heart of chemistry. People have always known that they exist. The Ancient Greeks were the first to speculate on the composition of matter. They thought that it was possible that individual particles made up matter. Later, in the Seventeenth Century, a German chemist named George Ernst Stahl was the first to postulate on chemical reaction.
He said that a substance called phlogiston escaped into the air from all substances during combustion. He explained that a burning candle would go out if a candle snuffer was put over it because the air inside the snuffer became saturated with phlogiston. Stahl also said that phlogiston will take away from a substance’s mass or that it had a negative mass, which contradicted his original theories. In the Eighteenth Century Antoine-Laurent Lavoisier, in France, discovered an important detail in the understanding of the chemical reaction combustion, oxigine (oxygen). He said that combustion was a chemical reaction involving oxygen and another combustible substance, such as wood.
John Dalton, in the early Nineteenth Century, discovered the atom. It led to the idea that a chemical reaction was actually the rearrangement of groups of atoms called molecules. Dalton also said that the appearance and disappearance of properties meant that the atomic composition dictated the appearance of different properties. He also came up with idea that a molecule of one substance is exactly the same as any other molecule of the same substance. People like Joseph-Lois Gay-Lussac added to Dalton’s ideas with the postulate that the volumes of gasses that react with each other are related.
Amedeo Avogadro also added to the understanding of chemical reactions. He said that all gasses at the same pressure, volume and temperature contain the same number of particles. This idea took a long time to be accepted. His ideas lead to the subscripts used in the formulas for gasses. From the work of these and many other chemists, we now have a mostly complete knowledge of chemical reactions. There are now many classification systems to classify the different types of reactions.
These include decomposition, polymerization, chain reactions, substitute reactions, elimination reactions, addition reactions, ionic reactions, and oxidation-reduction reactions. Bibliography “Chemical Reactions,” Webster Encyclopedia. 1993. Eastman, Richard H., General Chemistry: Experimental and Theory, Holt, Rhinehart, and Winston Inc., 1970 Pauling, Linus and Peter, Chemistry, W. H. Freeman and Co.,.