John Dalton's Atomic Theory

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Since as early as 500 B.C. philosophers have been concerned with the examining the composition of the universe. The early Greek philosopher, Thales, argued that the world was made up of one universal thing; water. It wasn’t until Democritus and the Atomist until philosophers began to rationalize about small particles called atoms as the things that make up the universe. As time approached the 18th century, advances in the scientific method gave rise to developing processes to examine the composition of gas molecules and the molecular weights of the atoms that make up chemical compounds. Throughout the rest of 18th century, investigation into chemical species continued and soon experimentation gave rise to laws and theories. One of the most …show more content…
In respect to water, Dalton claimed that the chemical formula for water to be HO. John Dalton realized in his atomic theory that there were some “striking regularities in the proportions by which various chemical substances combined with each other could be explained nicely if one assumed that chemical combination was the group together of atoms possessed of definite weights” (Chang 135). Thomas Thomson wrote in his history of chemistry “the atomic theory first occurred to Dalton during investigations of olefiant gas and carbureted hydrogen gas…Dalton found that if the amount of carbon was the same in each compound, then carburetted hydrogen gas contains exactly twice as much hydrogen as olefiant gas does” (qtd. in Greenaway 136). This allowed Dalton to theorize compounds such as NO, N2O, and NO2. In reading the papers that Dalton transcribed (circa 1802-1805), Dalton described several methods in which he varied the amount of Oxygen and Nitrogen gas in test tubes to examine the absorption of each product. Dalton was very particular about outlining his process so that his method could be reproducible. The quantitative description of his experiment goes into such detail as to outline the diameter and length of the test tube used, and the amount of measures of gas used in each trial. This shows the early importance of experimentation and varying variables in experiments in the design of experiments. The idea that chemical substances combine in specific ratios becomes one of the fundamental concepts that Cannizzaro uses to determine the existence of diatomic

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