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Chemical Chemical Reactions 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 George Ernst Stahl was the first to speak of chemical reaction, specifically, combustion.
He said that a substance called phlogiston escaped into the air from all substances during combustion. He said 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 Stahl, wood is made up of phlogiston and ash, because only ash is left after combustion. His ideas soon brought speculations of doubt. 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 substances mass or that it had a negative mass, which werent relevant to his original theories.
In the Eighteenth Century Antoine-Laurent Lavoisier, in France, discovered an important detail in the understanding of the chemical reaction combustion of 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 gave 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 concept 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. It is now known that there are three types of chemical reactions. They are classified into three types: exoergic (exothermic), endoergic (endothermic), and aortic (a thermic).
In these cases, energy is supplied, but the different types of reactions initiate the energy differently. Exoergic, or exothermic, reactions release energy during the reaction. Combustion is one of the major reactions that do this. The burning of wood, or any other fuel, gives off heat, and the burning of glucose in our bodies gives off both energy and heat. Endoergic, or endothermic, reactions absorb energy during the reaction.
The melting of an ice cube is an example of an endothermic reaction. Aergic, or a thermic, reactions neither give off nor absorb energy. There are very few cases in which this happens. Scientists today are still toying with chemical reactions. They are trying to control them with lasers. Scientists are trying to use lasers to provoke a chemical reaction that could go one way or another, the way they want it to.
They want to direct the molecules in one direction. The control of photons to excite molecules and cause reactions has been elusive. Recently, though, chemist Robert J. Gordon at the University of Illinois achieved coherent phase control of hydrogen disulfide molecules by firing ultraviolet lasers of different wavelengths at them. Laser chemistry looks promising and is a way that chemistry is still being expanded.
Again, chemical reactions are the main part of a branch of chemistry. Scientists are playing with chemical reactions. In April of 1995, a chemist named Peter Schultz and a physicist named Paul McEuen of the University of California at Berkley announced that they could control chemical reactions molecule by molecule. The key to the technique is to put a dab of platinum on the microscopic tip of an atomic force microscope. (The tip of such a microscope is a tiny cantilever that rides like a phonograph needle just above the surface of a sample and reacts to forces exerted by the electrons beneath it. ) The Platinum acts like a catalyst, stimulating a reaction between two reactants, were stimulating a reaction one molecule at a time. The molecules are stimulated in a pattern giving the wanted results. This discovery opens doors for nano engineering 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 overview 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.
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Research essay sample on Chemical Reactions Three Types
