CHEM 1124Q Chapter Notes - Chapter 2: Cathode Ray Tube, Unified Atomic Mass Unit, Hantaro Nagaoka
Document Summary
Chemical symbols are used to represent atoms and elements. Chemical formulas depict molecules as well as the composition of compounds. Chemical equations provide information about the quality and quantity of the changes associated with chemical reactions. Later, aristotle and others came to the conclusion that matter consisted of various combinations of the four. Elements fire, earth, air, and water and could be infinitely divided. John dalton helped to revolutionize chemistry with his hypothesis that the behavior of matter could be explained using an atomic theory. Many of dalton"s hypotheses about the microscopic features of matter are still valid in modern atomic theory. Here are the postulates of dalton"s atomic theory: matter is composed of exceedingly small particles called atoms. If atoms are neither created nor destroyed during a chemical change, then the total mass of matter present when matter changes from one type to another will remain constant (the law of conservation of matter).
