lecture2 - of Theory Matter 2.1Theatomic Dalton's theory...

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2.1 The atomic Theory of Matter . Dalton's atomic theory: 1. Each element is composed of extremely small particles called atoms. 2. All atoms of a qiven element are identical to one another in mass and othe-r properties, buy the atoms of one eldment are different from the atbms of all other elements. 3. The atoms of one element cannot be changed into atoms of a different element bv chemical reactions; atoms are neither created or destorytid in chemical reactions. 4- Compounds are formed when atoms of more than one elembnt combine; a given compound always has the same relative number and kind of atoms. . Dalton's theory can explain the following laws: 1. Law of constant composition: The elementral composition of a pure compound is al{vaYs the same 2. Law of conservation of mass:The total mass of materials present before and after a chemical reaction are same. 3. Law of multiple proportions: lf two element A and B combine to fonn more than bne compund, the masses of B that can combine with a given ma'ss of A are in the ratio of small whole number. Example 1: 'Hz 1.0 g 'Hz 1.0 g + Az -+ HaO 8.0g 9.09(n":no=2:1) + Oz * HrAz 16.09 17.09(nr:no=2:2) Example 2: A chemist finds that 30.829 of nitrogen will react with (1) 17.60 g, (2) 35.20 g, (3) 7A.40 g, or (4) 88.00 g of oxygen to form four different compounds. 1. Calculate
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2.2The Discovery of Atomic Structure (direct evidence) 1.
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This note was uploaded on 10/06/2008 for the course CHEM 121 taught by Professor Na during the Spring '08 term at John Brown Univeristy.

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lecture2 - of Theory Matter 2.1Theatomic Dalton's theory...

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