Chemistry is the science of the composition and structure of materials and of the changes that materials undergo. It is also used in improving standards of living, making it possible for such substances as rubber, nylon, and plastics to be made from completely different materials. New materials and new properties of old materials are always being discovered. Some earlier products discovered from chemical reactions are ceramics, glass, and metals. Dyes and medicines were other early products obtained from natural substances.
Some practical applications that chemistry is used for are to make stronger metals, improve soil, and the developments of live-saving drugs. Modern technology depends highly on these advancements; chemistry is a way of explaining our material world. Many people can’t understand the importance of chemistry if they aren’t planning on being a chemist. What many people don’t realize is that chemistry provides employment to people in laboratories, universities, schools, and businesses. A knowledge of chemistry is also needed in fields such as medicine, agriculture, and engineering.
Modern chemistry is only about two centuries old. Earlier history of chemistry can be divided into three periods: “black magic,” alchemy, and “primitive modern. ” Black magic was from prehistoric times to the beginning of the Christian Era. People believed that spirits controlled natural occurrences and they used magic to persuade these spirits to help in operations. During this period only some practical knowledge was gathered. Some elements such as iron, gold, and copper were recognized. There was also some progress in glass making, metalworking, and alloying.
Thales and Aristotle contemplated the nature of matter, and they believed that earth, air, fire and water composed all matter. They thought that they could remove certain qualities like hardness or temperature from common materials to make rarer substances. They did know that iron could be made from certain rock and that bronze was a mixture of copper and tin. From the beginning of the Christian Era to the 17th and 18th centuries was the period of chemistry known as alchemy. Alchemists believed that metals could be changed into gold with the help of a mystical stone which was never found.
They did, however, discover many new elements and compounds. Paracelsus, a talented Swiss alchemist, decided that alchemy should be for helping to cure the sick instead of searching for gold. The main elements that he used were salt, sulfur, and mercury, all which are connected to “elixir. ” This period of practicing medicine was known as iatrochemistry, which is the study of medicine with chemistry applied. One of the first real scientific chemist was Robert Boyle. In 1661, he helped to find the Royal Society of England, a scientific society.
For about two centuries after Boyle, scientists started making useful discoveries, even though, they were far from understanding the true nature of matter or knowing what happens in chemical reactions. One of the most confusing events of this time period was the theory of burning, or combustion, called the phlogiston theory. According to this theory, a yellowness or hardness was supposed to escape from substances during the burning process. By now, chemists were starting to learn that they must test these theories with experiments.
In 1774, Joseph Priestley discovered that a certain gas, now known as oxygen, was required in the burning process. A few years earlier, Henry Cavendish had discovered hydrogen and Antoine Lavoisier used the findings to formulate the presently accepted theory of combustion. This is often said to have marked the beginning of modern chemistry. In chemistry experiments must be run to prove hypothesizes that a chemist has stated. In an experiment you must make observations under circumstances in which variables can be controlled in a way that the results can be transcribed and rational conclusions can be obtained.
After an experiment has been carried out, a chemist can state a theory which is a tested explanation of a natural occurrence. Based on scientific principles, Chemistry didn’t evolve until the latter part of the 18th century. Chemists started to measure exactly what the substances were in their experiments. In 1805, John Dalton’s atomic theory helped to advance modern chemistry. This theory stated that all matter is made up of small particles called atoms and that chemical changes take place between these atoms and groups of atoms.
Soon after, Joseph Proust came out with the law of definite proportions and Joseph Gay-Lussac brought forth the law of definite proportions. Amedeo Avogadro also came out with the hypothesis, a planned explanation of a regularity in nature, that can be stated in modern terms: Equal volumes of all gases under the same conditions of temperature and pressure contain the same number of molecules. Jns Berzelis analyzed hundreds of compounds and published accurate tables of atomic weights in 1826. Friedrich Whler’s synthesis of urea in 1828 started organic chemistry beginning the concept of organic compounds having geometric structure.
In 1834, Michael Faraday started electrochemistry. Only about sixty elements were known by the middle of the nineteenth century. Dmitri Mendeleev published the first periodic table, which orders the chemically different kinds of atoms in a way that highlights similarities among the elements, in 1869. The table orders these elements in rows and columns, with all the elements arranged by atomic number. This table brought about the beginning of theoretical chemistry. Robert Bunsen also contributed to this period with the invention of the Bunsen burner and many other instruments used in modern chemistry.
Optical activity of some isomers was discovered by Louis Pasteur, whose work innovated biochemistry. Physical chemistry became important during the last part of the nineteenth century. William Oswald and Jacobus Van’t Hoff did work on chemical equilibriums while Svante August formulated a theory of ionization. Accurate atomic weights were determined by Theodore Richards and helium and other inert gasses were discovered by Rayleigh and Ramsay. After 1900, Francis Aston developed a machine to demonstrate the existence of isotopes, the mass spectrometer.
Harold Urey isolated an isotope of hydrogen which has become a very important chemical tracer in modern chemistry. By the twentieth century nuclear chemistry and physics were starting to evolve. In 1934, Joliot- Curies discovered that all elements could be made radioactive. By the 1940’s nuclear reactions had been performed with all elements from one to ninety-eight. In the first twenty-five years of the century, the interpretation of the structure of atoms was of important research. In the 1920’s and 30’s the nature of chemical reactions and the relationship between atoms and molecules was comprehendible.
One of chemistry’s most important advancements was in the development of new materials such as plastics. This new knowledge led to the production of materials with particular properties such as synthetic fibers and synthetic rubber. Some notable achievements in chemistry that people often use, but don’t appreciate the chemistry behind it are asprin, penicillin, and many other drugs used to fight diseases. In the past sixty years the pharmaceutical industry has grown tremendously due to advancements in chemistry. Another example is the ability to analyze and synthesize DNA and RNA.
Biochemists have also been able to produce hormones through genetic engineering. If it weren’t for chemistry, many diseases would have had a chance to infect large amounts of population and people might not be as healthy as they are in modern times. It’s hard for people to realize how much activity chemistry has in their daily lives. Chemistry is a very broad subject that has been divided into many special fields. Analytical chemistry determines the kind and amount of each element or compound present in a substance. Biochemistry is the study of chemical composition of living matter and the chemical process that occurs in living organisms.
Chemical engineering is a field that combines chemistry and engineering to develop or improve industrial processes. Colloid chemistry is the study of the behavior of particles of matter that are larger than ordinary molecules but smaller than objects that can be seen with an optical microscope. Electrochemistry is the study of chemical reactions that produce an electrical current. Carbon and its compounds are studied in organic chemistry. Elements and compounds that do not contain carbon are studied in inorganic chemistry.
Nuclear chemistry studies the radioactivity, atomic nucleus, and nuclear reactions, and the development for radioactive isotopes in medicine and industry. Physical chemistry applies physical methods to the study of chemical problems. A chemist intends to comprehend how the universe is put together and how its substances can be changed to meet mankind’s needs. All things can be classified as matter or energy and one can be converted to the other. Matter can also be classified by its physical state and according to its composition; matter also consists of particles in motion.
Chemists have discovered that the whole universe is made up of more than 90 molecules. Chemistry involves the study of these elements, and is used to help in technology for human welfare. Many people don’t seem to realize how many things they use every day have something to do with chemistry. There are many fields that involve chemistry, but for those that aren’t involved in these fields, it is good to have some knowledge of the field to be able to appreciate what it has done to make your life as simple as it is today.
