Mole Calculations

1
Mole Calculations
2
Visualizing a Chemical Reaction
2
Na Cl2
NaCl
2
?
10
5
10
10
5
10
___ mole Cl2
___ mole NaCl
___ mole Na
3
Formation of Ammonia
4
Proportional Relationships
3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2
c. chocolate chips Makes 5 dozen cookies.
2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1
c. butter 3/4 c. sugar
Conversion Factor

• I have 5 eggs. How many cookies can I make?

5 dozen
5 eggs
2 eggs
12.5 dozen cookies
150 cookies
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ationsarts/pages/chem
5
Proportional Relationships

• Stoichiometry
• mass relationships between substances in a
  chemical reaction
• based on the mole ratio
• Mole Ratio
• indicated by coefficients in a balanced equation

2 Mg O2 ? 2 MgO
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ationsarts/pages/chem
6
Stoichiometry Steps

• 1. Write a balanced equation.
• 2. Identify known unknown.
• 3. Line up conversion factors.
• Mole ratio - moles ? moles
• Molar mass - moles ? grams
• Molarity - moles ? liters soln
• Molar volume - moles ? liters gas

• Mole ratio - moles ? moles

Core step in all stoichiometry problems!!
4. Check answer.
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ationsarts/pages/chem
7
Molar Volume at STP
1 mol of a gas22.4 L at STP
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ationsarts/pages/chem
8
Molar Volume at STP
LITERS OF GAS AT STP
Molar Volume (22.4 L/mol)
MASS IN GRAMS
NUMBER OF PARTICLES
MOLES
Molar Mass (g/mol)
6.02 ? 1023 particles/mol
Molarity (mol/L)
LITERS OF SOLUTION
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ationsarts/pages/chem
9
Stoichiometry Problems

• How many moles of KClO3 must decompose in order
  to produce 9 moles of oxygen gas?

2KClO3 ? 2KCl 3O2
? mol
9 mol
9 mol O2
2 mol KClO3 3 mol O2
6 mol KClO3
Courtesy Christy Johannesson www.nisd.net/communic
ationsarts/pages/chem
10
1. 2 Sb 3 Cl2 ? 2 SbCl3 2. 2 Mg
O2 ? 2 MgO 3. CaCl2 ? Ca
Cl2 4. 2 NaClO3 ? 2 NaCl 3 O2
5. Fe 2 HCl ? FeCl2 H2 6. CuO
H2 ? Cu H2O 7. 2 Al 3 H2SO4 ?
Al2(SO4)3 3 H2
11
2
3
5 mol
x mol
1. 2 Sb 3 Cl2 ? 2 SbCl3
2 x 15
7.5 mol
5 mol
x mol
excess
x mol
excess
x 7. 5 mol
How many moles of chlorine gas are required to
react with 5 moles of antimony?
3 mol Cl2
x mol Cl2 5 mol Sb

7.5 mol Cl2
2 mol Sb
How many moles of SbCl3 are produced from 5 moles
of antimony and excess Cl2?
2 mol SbCl3
x mol SbCl3 5 mol Sb

5 mol SbCl3
2 mol Sb
How many moles of SbCl3 are produced from 7.5
moles of Cl2 and excess Sb?
2 mol SbCl3
x mol SbCl3 7.5 mol Cl2

5 mol SbCl3
3 mol Cl2
12
2. 2 Mg O2 ? 2 MgO
x mol
10 mol
x L
How many moles of magnesium oxide are produced
from the burning of 10 mol of Mg?
2 mol MgO
x mol MgO 10 mol Mg

10 mol MgO
2 mol Mg
How many liters of oxygen are needed to burn 10
mol of Mg?
Assume 1 mol O2 22.4 L
1 mol O2
22.4 L O2
x L O2 10 mol Mg

5 mol O2

112 L O2
2 mol Mg
1 mol O2
1 mol O2
22.4 L O2
x L O2 10 mol Mg

112 L O2
2 mol Mg
1 mol O2
13
3. CaCl2 ? Ca Cl2
x mol
8 mol
How many moles of calcium metal
are produced from the decomposition of
8 mol of calcium chloride?
and chlorine gas
1 mol Ca
x mol Ca 8 mol CaCl2

8 mol Ca
1 mol CaCl2
How many moles of calcium metal and chlorine gas
are produced from the decomposition of 8 mol of
calcium chloride?
1 mol Cl2
x mol Cl2 8 mol CaCl2

8 mol Cl2
1 mol CaCl2
14
Quantitative Relationships in Chemical Equations
          Quantitative Relationships in Chemical
Equations
          Quantitative Relationships in Chemical
Equations
Keys
http//www.unit5.org/chemistry/Equations.html
15
Chemical Equations (Paragraph Vocabulary)
          Chemical Equations (paragraph)
          Chemical Equations (paragraph)
Keys
http//www.unit5.org/chemistry/Equations.html
16
Real Life Chemistry (for the business world)
          Real Life Chemistry (for the business
world)
          Real Life Chemistry (for the business
world)
Keys
http//www.unit5.org/chemistry/Equations.html
17
Ions in Aqueous Solution
Print Copy of Lab
Pb(NO3)2(s)
Pb(NO3)2(aq)
H2O(l)
Pb2(aq) 2 NO31(aq)
add water
in solution
dissociation
NaI(s)
H2O(l)
NaI(aq)
Na1(aq) I1(aq)
Mix them and get Balance to get overall ionic
equation Cancel spectator ions to get net ionic
equation
18
Solubility Chart
Mix them and get
Pb(NO3)2(aq) 2 NaI(aq)
PbI2(s) 2 NO31(aq)
2 Na1(aq)
PbI2 NaNO3
(s)
(aq)
solid
in solution
Balance to get overall ionic equation
Cancel spectator ions to get net ionic equation
19
Solubility Chart
Mix together Zn(NO3)2(aq) and Ba(OH)2(aq)
Mix them and get
Ba(NO3)2 and Zn(OH)2
(aq)
(ppt)
Ba(OH)2(aq)
Zn(NO3)2(aq)
Zn2(aq) 2 NO31(aq)
Ba2(aq) 2 OH1(aq)
Balance to get overall ionic equation
Cancel spectator ions to get net ionic equation
20
?
6
(NH4)3PO4 Mg(OH)2 ? Mg3(PO4)2
NH4OH

2
3
ammonium phosphate
magnesium hydroxide
magnesium phosphate
ammonium hydroxide
NH41
OH1-
Now you try
AlCl3 Li2CO3 ? Al2(CO3)3
LiCl
3
2
6
21
Identify the spectator ions and write a net ionic
equation when an aqueous solution of aluminum
sulfate is mixed with aqueous ammonium hydroxide.
Al3
SO42-
NH41
OH1-
Al3
SO42-
NH41
OH1-
sulfate
hydroxide ?
aluminum
ammonium
aluminum
ammonium
aluminum hydroxide
ammonium sulfate

Al2(SO4)3(aq) 6 NH4OH(aq) ? 2 Al(OH)3
3 (NH4)2SO4
(ppt)
(aq)
2 Al3(aq) 3 SO42-(aq) 6 NH41(aq) 6
OH1-(aq) ? 2 Al(OH)3(ppt) 6 NH41(aq) 3
SO42-(aq)
spectator ions
2 Al3(aq) 6 OH1-(aq) ? 2 Al(OH)3(ppt)
Net Ionic Equation
22
Ions In Solution Lab
          Ions in Solution
          Ions in Solution
Keys
http//www.unit5.org/chemistry/Equations.html
23
Meaning of Coefficients
2 atoms Na
1 molecule Cl2
2 molecules NaCl
2 Na Cl2 2 NaCl
2 g sodium
1 g chlorine
2 g sodium chloride


2 mol sodium
1 mol chlorine
2 mol sodium chloride
(2 mol Na) x (23 g/mol)
(1 mol Cl2) x (71 g/mol)
(2 mol NaCl) x (58.5 g/mol)
117 g
46 g
71 g
117 g
24
Classes of Reactions
Chemical reactions
Precipitation reactions
Acid-Base Reactions
Oxidation-Reduction Reactions
Combustion Reactions
25
Summary of Classes of Reactions
Chemical reactions
Precipitation reactions
Acid-Base Reactions
Oxidation-Reduction Reactions
Combustion Reactions
Decomposition reactions (Products are
elements.)
Synthesis reactions (Reactants are elements.)
26
Summary of Classes of Reactions
Chemical reactions
Precipitation reactions
Acid-Base Reactions
Oxidation-Reduction Reactions
Combustion Reactions
Decomposition reactions
Synthesis reactions
27
IONIC BONDING Formation of Magnesium Chloride
Cl
Cl
Mg
Mg2
Cl
Cl
Loses 2e- Each gains 1e- One
magnesium ion Two chloride ions
Mg2 Cl1-

(2) 2 (1-)
0
MgCl2 magnesium
chloride
28
IONIC BONDING Formation of Magnesium Chloride
Cl
Cl
Mg2
Mg
Mg2
Cl
Cl
Loses 2e- Each gains 1e- One
magnesium ion Two chloride ions
Mg2 Cl1-

(2) 2 (1-)
0
MgCl2 magnesium
chloride
29
Production of Methanol
30
A Mixture of Molecules
31
KEYS Chemical Equations and Reactions
Worksheet - vocabulary
Worksheet Balancing Chemical Equations
Worksheet Chemical Word Equations
Worksheet Quantitative Relationships in Chem.
Eqns.
Worksheet Chemical Equations (paragraph)
Worksheet Real Life Chemistry
Worksheet Balancing Equations (visual)
Worksheet -
Lab Ions in Solution
Textbook - questions
Outline (general)
32
Resources - Chemical Equations and Reactions
Worksheet - vocabulary
Worksheet Balancing Chemical Equations
Worksheet Chemical Word Equations
Worksheet Quantitative Relationships in Chem.
Eqns.
Worksheet Chemical Equations (paragraph)
Worksheet Real Life Chemistry
Worksheet Balancing Equations (visual)
Worksheet -
Lab Ions in Solution
Textbook - questions
Outline (general)