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Explore the beauty of chemistry through Avogadro's Number and the mole concept, including conversion factors, formula masses, and the factor label method. Understand the significance of 6.02 x 10^23 in solving chemical problems and determining molar masses. Dive into the world of atoms, molecules, and compounds with this comprehensive guide.
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Chapter 8 Factor Label Method and the Mole
What is Avogadro’s Favorite Novel? Molby Dick
A ratio is an equality is a conversion factor. • Density of Aluminum = 2.7 g/cm3 • Land speed record = 763 miles/hr • 1.61 km = 1 mile • 1 pound = 0.4536 kilograms
What Do We Know About the Mole • 1 mol = 6.02 x 1023
What Do We Know About the Mole • 1 mol = 6.02 x 1023 • Any equality or ratio can be made into a conversion factor and then used to solve problems with the factor label method.
Avogadro’s Number as a Conversion Factor 6.02 x 1023 particles 1 mole or 1 mole 6.02 x 1023 particles Note that particles could be atoms, molecules, formula units, ions, etc.
A Mole of ParticlesContains 6.02 x 1023 particles = 6.02 x 1023 C atoms = 6.02 x 1023H2O molecules = 6.02 x 1023NaCl “molecules” (technically, ionic compounds are not molecules, they are called formula units) 1 mole C 1 mole H2O 1 mole NaCl
What Do We Know About the Mole • 1 mol of any substance = it’s gfm
What’s in a Name? • Atomic Mass/Atomic Weight/Molecular Mass/Molecular Weight/Formula Mass/Formula Weight: If you have a single atom or molecule or compound, mass is measured in amu’s. • Gram Atomic Mass/Gram Atomic Weight/Gram Molecular Mass/Gram Molecular Weight/Gram Formula Mass/Gram Formula Weight/Molar Mass: If you have a mole of atoms or molecules or a compound, mass is measured in grams. • But, the numerical value is the same whether you have 1 mole or one particle. Only the units are different. (This is the beauty of Avogadro’s Number!). • THE POINT: You may hear all of these termswhich mean the SAME NUMBER… just different units.
Gram Atomic Mass (Molar Mass) of an atom • Equal to the atomic mass (get from chart) • The mass of 1 mole (in grams) • 1 mole of C atoms = 12.0 g 1 mole of Mg atoms = 24.3 g 1 mole of Cu atoms = 63.5 g
Gram Formula Mass (Molar Mass) of Molecules and Compounds • Mass in grams of 1 mole • Equal to the formula mass (sum of the atomic masses) expressed in grams
Gram Formula Mass (Molar Mass) of Molecules and Compounds • Mass in grams of 1 mole • Equal to the formula mass (sum of the atomic masses) expressed in grams Gram Formula Mass of Ca3(PO4)2 • 3 x 40.1 = 120.3 • 2 x 31.0 = 62.0 • 8 x 16.0 = 128.0 = 310.3 g/mol
Homework • Homework: Factor Label Method Worksheet 2. • The equalities below will be useful for this assignment: L = dm3 ml = cm3