Chapter2-3 - 8/31/2011 CHEMISTRY 1307 Chapter II Atoms,...

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8/31/2011 1 1 CHEMISTRY 1307 Chapter II Atoms, Molecules, and Ions 2 The Mole Chemistry is a quantitative science - we need a ‘counting unit’ the: 1 mole is the amount of substance that contains as many particles (atoms, molecules) as there are in 12.0 g of 12 C. MOLE 518 g of Pb, 2.50 mol 3 Avogadro’s Number 6.0221415 10 23 Avogadro’s Number Named for Amedeo Avogadro 1776-1856 There is Avogadro’s number of particles in a mole of any substance.
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8/31/2011 2 4 Counting Atoms: The Mole The mole (mol) is a unit of measure for an amount of a chemical substance. A mole is Avogadro’s number of particles, which is 6.02 × 10 23 particles. 1 mol = Avogadro’s number = 6.02 × 10 23 units We can use the mole relationship to convert between the number of particles and the mass of a substance. 5 Molar Mass 1 mol of 12 C = 12.00 g of C = 6.022 x 10 23 atoms of C 12.00 g of 12 C is its MOLAR MASS Taking into account all of the isotopes of C, the molar mass of C is 12.011 g/mol One mole of several substances C 12 H 22 O 11 NaCl copper lead K 2 Cr 2 O 7 6 Grams, Moles, & Molar Mass The molar mass of an atom is a conversion factor that relates mass (grams) to moles and vice versa. (how much matter) (number of atoms) g mol Avogadro's number (N A ) relates moles numbers of individual particles: 1 mol 6.022 10 23 particles  23 6.022 10 particles mol
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8/31/2011 3 7 Mass/Moles Conversions 8 Practice – moles to grams 1 mole of Ar is 39.948 grams
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This document was uploaded on 10/30/2011 for the course CHEM 1307 at Texas Tech.

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Chapter2-3 - 8/31/2011 CHEMISTRY 1307 Chapter II Atoms,...

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