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Wednesday, January 19, 2011

Great Discoveries in Chemistry

Great Discoveries in Chemistry


It was first suggested by Leonardo Da Vinci that the air was made up of two gases. Later on in 1774, Joseph Priestley did an experiment with mercury to find out if Da Vinci was correct. Priestley came across a gas with an unusual property. This gas would come to be known as oxygen. Basically Priestley literally discovered oxygen, but it was Antoine Lavoisier who really discovered it. Lavoisier was notified of Priestley's discovery by Priestly himself. Lavoisier redid Priestley's experiments and named the gas oxygen. Then John Dalton made a tremendous discovery. He came up with an atomic theory. Dalton proclaimed that atoms of a certain element are unlike any other atom of another element, atoms of the same element are alike, chemical compounds can be created when atoms from different elements combine, atoms cannot be created, divided, or destroyed, and that atoms make up elements. Dalton also discovered atomic weights which he called ultimate particles, and weight of elements. Also in the early 1800s Joseph Louis combined equal volumes of gases to find out that they had equal reactions. It was discovered that gases were not made out of single atoms, but multiple ones which were molecules. Then in the 19th century urea was discovered. A scientist noticed that something had crystallized in one of his tubes with two organic chemicals. The theory of organic chemical reactions had been stumbled upon! It was the underlying base and building block of organic compounds. Then August Kekule created a device for chemical molecules, using symbols resembling chain links. But there was one compound that would not fit his equation. Kekule was puzzling over it when he dreamt of a snake that bit its tail to form a ring. The six carbon atoms of benzine were discovered, they form a ring, like the snake. One or more carbon atom is inside every organic compound. This meant a new recipe for medicine and wonderful possibilities. Then in 1869, a German teacher named Demetri Mendelev created the periodic table of elements. He needed a way to teach them all to his students so he wrote out 63 elements on cards and sorted them and wrote their atomic weight, typical properties, and similarities. When he was complete, he realized he had created a map showing exact relationships between elements. Mendelev had forever changed the way of learning and comprehending the elements. There is an element named after him, Mendelevium. Then Humphrey Davie in 1807 conducted a battery experiment with melted pot ash. Pure potassium emerged, this brought about aluminium, solar panels, LED, and lithium batteries. Next was Robert Bunsen and Kierkoff in the 1850s. They conducted an experiment with a prism and pieces of a telescope. The end result? A spectroscope. With this new instrument they saw a spectrum of colors and dark lines that indicated what atoms were present. Cesium was discovered using this. Then a professor at Cambridge, Joseph Thompson, discovered he could extract a small piece from an atom while trying to find the ratio of charge in mass. Thompson discovered a subatomic particle. Later on Earnest Russerford showed positive sides of atoms located in the nuclei. A mechanism to combine atoms and create new substances was discovered by Gilbert Lewis. Separately sodium and chloride can be dangerous, but it was discovered that when sodium gives an electron from its outer shell to chlorine's outer shell, it forms sodium-chloride: table salt. Then there were the X-Rays . Investigation on special radiation/mysterious radioactive rays French Physicist, Ambre Beckrow tested uranium put objects on top of photographic plate develop plate, ghostly image would appear. He
discovered it was uranium. Marie Curie/husband boiled and sifted uranium, isolated two of them, radium and polonium. In a way, Marie Curie discovered radiation poisoning. Earnest Rutherford discovered radioactive material goes through natural decaying process emits unstable rays. Came across alpha and beta particles and gamma rays. Radioactivity has given us a method for earth's age calculation, spacecraft power source, cancer treatment, smoke alarms
Then there was the discovery of plastics in the 1860s, John Hyatt had discovered a way to exploit cellulose by creating plastic. Leo Bakeland came up with Bakelite, a polymer which are long chain molecules that are extended chains of carbon atoms, sometimes other objects. Plastic is moldable and strong and can mimic/surpass natural fibers. Making polyethlane, plexiglass, etc. polymers are example of human creativity in chemistry. Nanotubes are 1 billionth of a meter, thinner than DNA strands. Richard Smalley studied chemical conditions in space
searching for chemical nature of interstellar matter. A cluster of carbon atoms (60 approx. named buckyballs. Formally known as fullerenes. Most symmetry than any other molecule discovered. Then new fullerenes were discovered, pure carbon forming nanotubes, buckytubes. Have 12 pentagons, buckytubes are stiffer than steel/diamond. They are very stretchy, the strongest fiber ever. We can convert coal/tires/etc. into buckytubes. It is thought that carbon nanotubes are the modern day Industrial Revolution. Nanotechnology is, technically speaking, chemistry.

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