CHEM 111 Lecture Notes - Lecture 3: Significant Figures, Gallium, Bromine
21 Dec 2015
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Chem111 lecture 3 the microscopic scale and significant figures. Many chemical reactions give out heat are exothermic. Some reactions take in heat, temperature goes down (endothermic) Reactions occur because the system can go to a lower energy . Endothermic reactions occur if the forward reaction generates a lot of molecules, now the reverse reaction is very slow. If very strong bonds have to be broken an exothermic reaction can be slow. The study of the energy of chemical reactions and how the energy is dispersed is known as thermodynamics. The study of the speed of reactions is known as kinetics. Atoms and molecules are moving all the time. Particulate representations show the molecules and atoms. Microscopic representations are ones that you cannot see with the naked eye. Macroscopic representations are ones that we can see without visual aid. Distinguish between physical chemical properties and changes. Physical: no change in chemical composition; chemical bonds are broken or formed.
