Chemical Reactions Essay -- science

Chemical Reactions Chemical reactions are the heart of chemistry. People have always known that they exist. The Ancient Greeks were the firsts 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 Georg Ernst Stahl was the first to postulate on chemical reaction, specifically, combustion. 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. According to his ideas, wood is made up of phlogiston and ash, because only ash is left after combustion. His ideas soon came upon some contradiction. When metal is burned, its ash has a greater mass than the original substance. Stahl tried to cover himself by saying 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 gave way 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 concepts with the postulate that the volumes of gasses that react with each other are related (14 grams of nitrogen reacted with exactly three grams of hydrogen, eight grams of oxygen reacted to exactly one gram of hydrogen, etc.) 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 f... ...st, stimulating a reaction between two reactants, just stimulating a reaction one molecule at a time. The molecules are stimulated in a pattern giving the wanted results. This discovery opens doors for nanoengineering and material sciences. It gives a good view of what happens, one molecule at a time. Chemical reactions are a large part of chemistry. This paper is an overveiw of that extensive subject. It gives a good idea about the history of chemical reactions as well as the future. Hopefully, there will be no end to the expansion of chemistry and our knowledge. Since Scientists are still experimenting, chemical reactions will always be a part of chemistry. Bibliography "Chemical Reactions," Encyclopedia Brittanica MACROPEDIA, 1995, Vol. 15 "Dances With molecules," Science News, Vol. 147, May 27, 1995 Eastman, Richard H., General Chemistry: Experimental and Theory, Holt, Rhinehart, and Winston Inc., 1970 "One Molecule at a Time", Discover, January 1996 Pauling, Linus and Peter, Chemistry, W. H. Freeman and Co., 1975 "Reactions, Chemical," Encyclopedia Americana, 1982, Vol. 23 "Reactions, Chemical," Academic American Encyclopedia, 1991, Vol. 16