Chemistry Notes 4

Chemistry Notes 4 - 63 Cu and 30.91% 65 Cu where 63 Cu is...

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Chemistry Notes: STOICHIOMETRY: Mass (not weight) F = mg Weight (newtons) = Mass (kg) Mole: Definition: The mol is as number equal to the number of C atoms in 12,000 g of 12 C Corollaries: By experiment, 1 mol = 6.022 x 10 23 For any element, 1 mol = the number of atoms equal to the atomic mass. AMU: The Atomic Mass Unit is the mass of a single atom, based on 12 C mass = 12 amu NOTE: Table of atomic masses of elements give average mass for all isotopes. (Natural abundance) Ex problem: Cu is 69.09%
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Unformatted text preview: 63 Cu and 30.91% 65 Cu where 63 Cu is 62.93 amu, and 65 Cu is 64.93 amu. Calc. average A.M. Solution: 0.6909 mol 63Cu x 62.93 g 63 Cu + 0.3091 mol 65 Cu x 64.93 g 65Cu = 1 mol Cu 1 mol 63 Cu 1 mol Cu 1 mol 65 Cu 43.48 g 63Cu + 20.07 g 65Cu = 63.55 g (63Cu + 65Cu) 1 mol Cu 1 mol Cu Molar Mass is the mass in grams of 1 mole. EMPIRICAL FORMULA Ex: Gallic acid is composed of: 49.39%C 3.534% H 47.08% O Molar Mass = 170.12 g/mol What is its formula?...
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This note was uploaded on 04/08/2008 for the course CHEM 112 taught by Professor Jones during the Fall '07 term at Stevens.

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