Chapter 10: The Mole
Mole: Unit used in chemistry to quantify atoms because atoms are so
tiny.
Mole = 602, 213, 670, 000, 000, 000, 000, 000 or 6. 02 X 1023
This is Avogadro’s number.
How many eggs are in 12 dozen?
12 𝑑𝑜𝑧𝑒𝑛 𝑥
12 𝑒𝑔𝑔𝑠
= 144 𝑒𝑔𝑔𝑠
1 𝑑𝑜𝑧𝑒𝑛
How many eggs are in 12 moles?
6.02 𝑥 1023 𝑒𝑔𝑔𝑠
12 𝑚𝑜𝑙𝑒𝑠 𝑥
= 7.224 𝑥 10 24 𝑒𝑔𝑔𝑠
1 𝑚𝑜𝑙𝑒
I have 246 eggs, how many dozen do I have?
246 𝑒𝑔𝑔𝑠 𝑥
1 𝑑𝑜𝑧𝑒𝑛
= 20.5 𝑑𝑜𝑧𝑒𝑛 𝑜𝑓 𝑒𝑔𝑔𝑠
12 𝑒𝑔𝑔𝑠
If I have 5.60 X 1023 eggs, how many moles of eggs do I have?
5.60 𝑥 1023 𝑒𝑔𝑔𝑠 𝑥
1 𝑚𝑜𝑙𝑒
= 0.93 𝑚𝑜𝑙𝑒𝑠
6. 02 𝑥 1023
How many representative particles are in 3.50 moles of sucrose?
(Representative particle = ANYTHING!!! Usually: Atoms, Molecules,
formula units)
Now: Work Page 323: 1-4 & Page 324: 5 & 6
1. Determine the number of atoms in 2.50 moles of Zn.
6.02 𝑥 1023
2.50 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑍𝑛 𝑥
= 1.51 𝑥 1024 𝑎𝑡𝑜𝑚𝑠
1 𝑚𝑜𝑙𝑒
2. Calculate the number of molecules in 11.5 mol of water.
3. How many formula units of AgNO3 are in 3.25 mol of AgNO3?
4. Calculate the number of oxygen atoms in 5 mol of oxygen molecules.
Remember oxygen is diatomic.
5. How many moles contain each of the following?
a. 5.75 x 1024 atoms Al
b. 2.50 x 1020 atoms Fe
6. Identify the representative particles of each formula and convert the
given number of rep. particles to moles.
a. 3.75 x 1024 CO2
b. 3.58 x 1023 ZnCl2
10.2: Mass and the Mole
A mole always contains the same number of particles; however, moles of
different substances have different masses.
Molar mass: the mass in grams of one mole of any pure substance.
Molar mass of an element = atomic mass of that element.
Molar mass of a compound? What is it equal to? Molar mass of a
compound is equal to the mass of each of the elements in the compound.
Ex. NaCl
Na: 1 x 23= 23
Cl: 1 x 35= 35
23 + 35 = 58 grams
Ex. H2SO4
H: 2 x 1 = 2
S: 1 x 32 = 32
O: 4 x 16 = 64
2 + 32 + 64 = 98 grams
Practice: Find the molar mass:
H2O2
H: 2 X 1 = 2
O: 2 x 16 = 32
2 + 32 = 34 grams
CH3COOH
C: 2 x 12= 24
H: 4 x 1= 4
O: 2 x 16 = 32
24 + 4 + 32 = 60 grams
Ca3(PO4)2
Ca: 3 x 40 = 120
P: 2 x 31 = 62
O: 8 x 16 = 128
120 + 62 + 128 = 310 grams
AgNO3
Ag: 1 x 108 = 108
N: 1 x 14 = 14
O: 3 x 16 = 48
108 + 14 + 48 = 170 grams
C2H6O
C: 2 X 12 = 24
H: 6 x 1 = 6
O: 1 x 16 = 16
24 + 6 + 16 = 46 grams
1 dozen jelly beans = 35 grams. How much does 5 dozen weigh?
5 𝑑𝑜𝑧𝑒𝑛 𝑥
35 𝑔𝑟𝑎𝑚𝑠
1 𝑑𝑜𝑧𝑒𝑛
= 175 𝑔𝑟𝑎𝑚𝑠
How much does 3 moles of copper weigh?
3 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶𝑢 𝑥
64 𝑔𝑟𝑎𝑚𝑠 𝐶𝑢
1 𝑚𝑜𝑙𝑒 𝐶𝑢
= 192 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝐶𝑢
Calculate the mass in grams of 0.0450 mole Cr.
0.0450 𝑚𝑜𝑙𝑒 𝐶𝑟 𝑥
52 𝑔𝑟𝑎𝑚𝑠
= 2.34 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝐶𝑟
1 𝑚𝑜𝑙𝑒 𝐶𝑟
Determine the mass in grams of each of the following:
a. 3.57 mole Al
27 𝑔𝑟𝑎𝑚𝑠 𝐴𝑙
3.57 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐴𝑙 𝑥
= 96.39 𝑔𝑟𝑎𝑚𝑠 𝐴𝑙
1 𝑚𝑜𝑙𝑒 𝐴𝑙
b. 42.6 mole Si
42.6 𝑚𝑜𝑙𝑒𝑠 𝑆𝑖 𝑥
28 𝑔𝑟𝑎𝑚𝑠 𝑆𝑖
= 1192.8 𝑔𝑟𝑎𝑚𝑠 𝑆𝑖
1 𝑚𝑜𝑙𝑒 𝑆𝑖
525 grams of Ca = ? moles
1 𝑚𝑜𝑙𝑒 𝐶𝑎
525 𝑔𝑟𝑎𝑚𝑠 𝐶𝑎 𝑥
= 13.125 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶𝑎
40 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝐶𝑎
25.5 grams of Ag = ? Moles
1 𝑚𝑜𝑙𝑒 𝐴𝑔
25.5 grams of Ag x 108 𝑔𝑟𝑎𝑚𝑠 𝐴𝑔 = 0.236 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐴𝑔
300 grams of S = ? Moles
1 𝑚𝑜𝑙𝑒 𝑆
300 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝑆 𝑥
= 9.37 𝑚𝑜𝑙𝑒𝑠 𝑆
32 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝑆
If 1 dozen jelly beans weigh 35 grams, how many jelly beans are in 280
grams of jelly beans?
280 𝑔𝑟𝑎𝑚𝑠 𝑗𝑒𝑙𝑙𝑦 𝑏𝑒𝑎𝑛𝑠 𝑥
1 𝑑𝑜𝑧𝑒𝑛 𝑗𝑏
35 𝑔𝑟𝑎𝑚𝑠 𝑗𝑏
𝑥
12 𝑗𝑏
1 𝑑𝑧 𝑗𝑏
=
96 𝑗𝑒𝑙𝑙𝑦 𝑏𝑒𝑎𝑛𝑠
How many atoms of gold are in 31.1 grams of Au?
1 𝑚𝑜𝑙𝑒 𝐴𝑢
6.02 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
31.1 𝑔𝑟𝑎𝑚𝑠 𝐴𝑢 𝑥
𝑥
= 9.50 𝑥 1022
197 𝑔𝑟𝑎𝑚𝑠 𝐴𝑢
1 𝑚𝑜𝑙𝑒 𝐴𝑢
How many atoms are in the following:
a.
b.
c.
55.2 grams of Li
1 𝑚𝑜𝑙𝑒 𝐿𝑖 6. 02 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
55.2 𝑔𝑟𝑎𝑚𝑠 𝐿𝑖 𝑥
𝑥
7 𝑔𝑟𝑎𝑚𝑠 𝐿𝑖
1 𝑚𝑜𝑙𝑒 𝐿𝑖
= 4.75 𝑥 1024 𝑎𝑡𝑜𝑚𝑠 𝑜𝑓𝐿𝑖
0.230 grams of Pb
1 𝑚𝑜𝑙𝑒 𝑃𝑏
6.02 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
0.230 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝑃𝑏 𝑥
𝑥
207 𝑔𝑟𝑎𝑚𝑠 𝑃𝑏
1 𝑚𝑜𝑙𝑒 𝑃𝑏
= 6.69 𝑥 1020 𝑎𝑡𝑜𝑚𝑠
11.5 grams of Hg
What is the mass of 6.02 𝑥 1024 𝑎𝑡𝑜𝑚𝑠 𝑜𝑓 𝐵𝑖?
1 𝑚𝑜𝑙𝑒𝑠
209 𝑔𝑟𝑎𝑚𝑠 𝐵𝑖
6.02 𝑥 10 𝑎𝑡𝑜𝑚𝑠 𝑜𝑓 𝐵𝑖 𝑥
𝑥
6.02 𝑥 1023 𝑎𝑡𝑜𝑚𝑠
1 𝑚𝑜𝑙𝑒𝑠
= 2090 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝐵𝑖
24
What is the mass of 1.00 x 1024 atoms of Mn?
1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑀𝑛
55 𝑔𝑟𝑎𝑚𝑠 𝑀𝑛
𝑥
6.02 𝑥 1023 𝑎𝑡𝑜𝑚𝑠 𝑜𝑓 𝑀𝑛 1 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑀𝑛
= 91.36 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝑀𝑛
1.00𝑥1024 𝑎𝑡𝑜𝑚𝑠 𝑜𝑓 𝑀𝑛 𝑥
On separate sheet of paper:
Classwork/Homework: Page 358-359: Problem #’s 84, 86, 88, 90, 91, 92,
93, 94, 95, 99, 102, 103, 104, 108, 109, 110, 112, 113, 116, 119.
Chapter 10.3: Moles of Compounds
Representative Particles:
Elements = atoms
Ionic bonds = Compounds (metal and nonmetal) = formula units
Covalent bonds (nonmetal and nonmetal) = molecules
We find moles of compounds just like we did before, except we use
molar mass.
Answer:
How many moles of Cl- are in 2.5 moles ZnCl2?
2 𝑚𝑜𝑙𝑒𝑠 𝐶𝑙 −
2.5 𝑚𝑜𝑙𝑒𝑠 𝑍𝑛𝐶𝑙2 𝑥
=5
1 𝑚𝑜𝑙𝑒 𝑍𝑛𝐶𝑙2
How many moles of oxygen atoms are present in 5 moles of P2O5?
5 𝑚𝑜𝑙𝑒𝑠 𝑃2 𝑂5 𝑥
5 𝑚𝑜𝑙𝑒𝑠 𝑂
1 𝑚𝑜𝑙𝑒𝑃2 𝑂5
= 25 moles O
What is the molar mass of the following?
NaOH
Na: 1 x 23 = 23
O: 1 x 16 = 16
H: 1 x 1 = 1
HCN
H: 1 x 1 = 1
C: 1 x 12 = 12
23 + 16 + 1 = 40 grams
N: 1 x 14 = 14 1 + 12+ 14 = 27 grams
CaCl2
CCl4
What is the mass of 2.50 moles of (C3H5)2S?
C: 6 x 12 = 72
H: 10 x 1 = 10
S: 1 x 32 = 32 72+10+32 = 114 grams
2.5 𝑚𝑜𝑙𝑒𝑠 x
114 𝑔𝑟𝑎𝑚𝑠
= 285 𝑔𝑟𝑎𝑚𝑠
1 𝑚𝑜𝑙𝑒
How many moles are in 325 grams of Calcium Hydroxide, Ca(OH)2?
1 𝑚𝑜𝑙𝑒 𝐶𝑎(𝑂𝐻 )2
325 𝑔𝑟𝑎𝑚𝑠 𝑜𝑓 𝐶𝑎(𝑂𝐻)2 x
74 𝑔𝑟𝑎𝑚𝑠 𝐶𝑎(𝑂𝐻 )2
= 4.39 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐶𝑎(𝑂𝐻)2