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/cm 3 Land speed record = 763 miles/hr 1.61 km = 1 mile 1 pound = kilograms

What Do We Know About the Mole

1 mol = 6.02 x 10 23

What Do We Know About the Mole 1 mol = 6.02 x Any equality or ratio can be made into a conversion factor and then used to solve problems with the factor label method.

6.02 x particles 1 mole or 1 mole 6.02 x particles Note that particles could be atoms, molecules, formula units, ions, etc. Avogadro’s Number as a Conversion Factor

= 6.02 x C atoms = 6.02 x H 2 O molecules = 6.02 x NaCl “molecules” (technically, ionic compounds are not molecules, they are called formula units) A Mole of Particles A Mole of Particles Contains 6.02 x particles 1 mole C 1 mole H 2 O 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 terms which mean the SAME NUMBER… just different units.

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 Atomic Mass (Molar Mass) of an atom

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 Ca 3 (PO 4 ) 2 3 x 40.1 = x 31.0 = x 16.0 = = g/mol Gram Formula Mass (Molar Mass) of Molecules and Compounds

Homework  Homework: Factor Label Method Worksheet 2.  The equalities below will be useful for this assignment: L = dm 3 ml = cm 3