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A history of the discoveries of chemical reactions

In many cases the properties of a mixture are determined primarily by forces that are more properly classified as chemical rather than as physical. For example, when dinitrogen pentoxide is dissolved in water, a new substance, nitric acid, is formed; and it is… Historical overview The concept of a chemical reaction dates back about 250 years. It had its origins in early experiments that classified substances as elements and compounds and in theories that explained these processes.

History of chemistry

Development of the concept of a chemical reaction had a primary role in defining the science of chemistry as it is known today. The first substantive studies in this area were on gases. The identification of oxygen in the 18th century by Swedish chemist Carl Wilhelm Scheele and English clergyman Joseph Priestley had particular significance. The influence of French chemist Antoine-Laurent Lavoisier was especially notable, in that his insights confirmed the importance of quantitative measurements of chemical processes.

  1. Also known by his Latinized name, Geber, he is known as the "father of chemistry. A redox reaction is one where reduction and oxidation take place together, hence the name.
  2. Using the example of the Daniell cell above, Equation 5 Oxidation. The loss from one species cannot happen without the other species gaining.
  3. He determined the exact elementary constituents of large numbers of compounds.
  4. The individual processes of oxidation and reduction can be defined in more than one way, but whatever the definition, the two processes are symbiotic, i.
  5. But what was the correct formula for each compound? In this example, the reactants zinc and two hydrogen chloride molecules convert into different products zinc chloride and dihydrogen , but no mass is lost or created.

Among his many discoveries, Lavoisier accurately measured the weight gained when elements were oxidized, and he ascribed the result to the combining of the element with oxygen. The concept of chemical reactions involving the combination of elements clearly emerged from his writing, and his approach led others to pursue experimental chemistry as a quantitative science.

The other occurrence of historical significance concerning chemical reactions was the development of atomic theory.

  • Following Lavoisier's work, chemistry acquired a strict quantitative nature, allowing reliable predictions to be made;
  • In one definition, oxidation is described as the process in which a species loses electrons , and reduction is a process where a species gains electrons.

For this, much credit goes to English chemist John Daltonwho postulated his atomic theory early in the 19th century. Dalton maintained that matter is composed of small, indivisible particles, that the particles, or atomsof each element were unique, and that chemical reactions were involved in rearranging atoms to form new substances.

This view of chemical reactions accurately defines the current subject. Thus, experiment and theory, the two cornerstones of chemical science in the modern world, together defined the concept of chemical reactions. Today experimental chemistry provides innumerable examples, and theoretical chemistry allows an understanding of their meaning.

Chemical reaction

Basic concepts of chemical reactions Synthesis When making a new substance from other substances, chemists say either that they carry out a synthesis or that they synthesize the new material. Reactants are converted to products, and the process is symbolized by a chemical equation.

J. Willard Gibbs

For example, iron Fe and sulfur S combine to form iron sulfide FeS. The state of matter of reactants and products is designated with the symbols s for solidsl for liquidsand g for gases. Page 1 of 7.