Chemistry
Lesson 10.1
“The Mole”
I. Measuring Matter
A. 3 ways…
1. counting (#’s)
2. mass (gram, pound…)
3. volume (liter, gallon…)
B. Units of measurement…
1. pair = 2
2. dozen = 12
3. ream = 500
I. What is a mole?
A. Def – the S.I. unit that measures an
amount or quantity.
1. similar to others: dozen, ream,
bakers dozen, gross, hour, day…
B. 1 mole = 6.02 x 1023 particles
1. called Avogadro’s number
2. Usually refers to atoms, molecules,
or formula units (Fe, H2O, CaCl2)
C. Why such a big number?
1. Atoms are microscopic
2. 602,000,000,000,000,000,000,000
3. We need to be precise in chemistry
D. Problems
1. How many moles of iron do you have with
2.41 x 1024 atoms?
= 4.00 moles of iron
2. I have 3.3 x 1022 formula units of NaCl.
How many moles is this?
=0.055 moles of NaCl
3. I have 9.76 x 1025 molecules of N2. How
many moles is this?
=162 moles
4. How many molecules are in 2.12 mol of
propane (C3H8)?
2.12 mol x (6.02 x 1023) propane molecules
1
1 mol
=1.28 x 1024 propane molecules
5. How many atoms of propane are found in
1.28 x 1024 molecules of propane?
1.28 x 1024 molecules x 11 atoms
1
1 molecule (C3H2)
=1.41 x 1025 atoms
7. With a partner create a question
similar to others used today and
answer it.
Then write the same question down
and trade it with another group.
Grade it when they are done.
Assignment 7.1
1.
2.
3.
4.
5.
How many atoms are in 4.10 mol of
C6H12O6? 5.92 x 1025 atoms
How many molecules are in 0.750 mol of
H2O? 4.52 x 1023 molecules
How many C atoms are in 0.890 mol of
C6H12O6? 3.21 x 1024 Carbon atoms
How many H atoms are in 1.23 mol of
C6H12O6? 8.89 x 1024 Hydrogen atoms
How many mol are found in 6.02 x 1027
molecules of H2O? 1.00 x 104 mol of water
II.
How much does a mole
weigh?
A. Gram atomic mass (single elements)
1. Def – how much 1 mole of an
element weighs in grams.
2. Ex: Carbon = 12.01 g
3. Others:
P = 30.97 K = 39.10 Ag = 107.87
Fe = 55.85 Ar = 39.95 Li = 6.94
B. Gram Molecular Mass
1. Def – the mass of one mole of a
molecular compound.
2. Use atomic values and add
together = GMM
3. Ex: SO3
S = 32.06
O = 16.00 (3)
32.06 + 48.00 = 80.06 g
4. Examples
PO4 94.97
H 2O
PCl3
18.02
137.32
C8H18
SO4
N 2O 5
114.26
96.06
108.02
C. Gram Formula Mass
1. Def – the mass of one mole of an
ionic compound.
2. Just like GMM
3. Ex: NaCl
Na = 22.99
Cl = 35.45
22.99 + 35.45 = 58.44
4. Examples
CaI2 293.88
Li3N
34.83
Fe2O3
159.70
Na3PO4
AlCl3
163.94
133.33
Al(OH)3
78.01
Assignment: Read 10.2 for Thursday.