Transcript 1 mol = 6.02 x 10 23

Chapter 8
Factor Label Method
and the Mole
What is Avogadro’s Favorite Novel?
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
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 Particles
Contains 6.02 x 1023 particles
1 mole C
= 6.02 x 1023 C atoms
1 mole H2O = 6.02 x 1023 H2O molecules
1 mole NaCl = 6.02 x 1023 NaCl “molecules”
(technically, ionic compounds
are not molecules, they are called
formula units)
What Do We Know About the Mole
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.
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
Gram Atomic Mass (Molar Mass) of
an atom
1 mole of Mg atoms
24.3 g
Gram Atomic Mass (Molar Mass) of
an atom
1 mole of Cu atoms
63.5 g
Gram Formula Mass (Molar Mass)
of Molecules and Compounds
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
List “2” things you know about a
mole of H.
• 1 mole H = 6.02 x 1023 H atoms
• 1 mole H = 1.0g
• What could we use these equalities to
do in a factor label problem?
List “2” things you know about a
mole of H2O
• 1 mole H2O = 6.02 x 1023 H2O molecules
• 1 mole H2O = 18.0g
List “2” things you know about a
mole of Na2O
• 1 mole Na2O = 6.02 x 1023 Na2O formula units
• 1 mole Na2O = 62.0g