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350
Two great philosphers
Aristotle and Socrates were two great philosophers that believed in the four elements by Empedocles and rejected Democritus atom theory. Resulting in Empedocles idea lasting 2000 years; people went a long with it because Socrates was a very influential figure at the time. -
400
Greek Philosopher Democritus
Democritus suggested that matter consisted of particles that could not be broken down any further. He called the particles atoms, after the Greek word atomos, which means uncuttable. He was born 460B.C and died 370B.C -
450
Greek Scholer Empedocles
Empedocles believed that matter was made up of four elements earth, air, fire, and water. Each element is a mixture of two properties. The combination and separation of elements was Empedocles theory on humans emotion of love and hate. He was born in 490 B.C and died in 430 B.C -
Period: 450 to
History of Chemistry
450 B.C to 2000 -
Alchemies
The Alchemies believed that they could change substances into others for example change cheap metal into valuable ones, find eternal life, and produce solvent that dissolves all substances.The Alchemies relied more on spiritual chants then scientific methods. In 1669 Branks needed 50 buckets of urane so he could boil it and try and make gold from it. -
Robert Boyle
Robert Boyles definition of an element is a pure substance that is not mixed with any other substances. He belevied that air is not an element but a mixture. Boyle wrote the first book of chemistry, and shared secrets for the good of science. Born 1627 and died 1691. -
Henry Cavendish
By mixing metal and acid Cavendish's experiments resulted in the finding of a flammable gas which was lighter than air. It was called hydrogen and was 11x lighter than air. when he burned it with some of Priestly's oxygen it produced water, until then people thought water was an element. -
Joseph Priestly
Priestly was the first person to isolate oxygen, by heating mercury oxide. Pure oxygen and mercury where produced from this process. He made the first fizzy drink and was the first cemist to make money. The human body is made of 1/3 oxygen and the air has 21% oxygen any more or less and we couldn't survive. -
Antoine Lavoiser
Antoine Lavoiser was testing Priestley's oxygen and concluded that air has a mixture of at least two gases. He was the first scientist to explain what an element was and come to the conclusion that phlogiston didnt exist. Lavoiser grouped the elements as earths, metals, unmetals, and gases.He was a tax collecter and was found guilty of tax fraud resulting in his execution. -
John Dalton
Elements differ from each other and from non elements was a published theory by english chemist John Dalton. His atomic model for matter listed that:
*Atoms make up of matter
*Every atom is different and has it's own particular mass
*Atoms linking together to form molecules are called compounds
*Chemical change can't create destroy or subdivide
