Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Modern ChemistryModern ChemistryChapter 9Chapter 9
StoichiometryStoichiometry
Sections 1-3Introduction to Stoichiometry
Ideal Stoichiometric CalculationsLimiting Reactant and Percent Yield
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Chapter 9 VocabularyChapter 9 Vocabulary• Composition Stoichiometry• Reaction Stoichiometry• Mole Ratio• Limiting Reactant• Excess Reactant• Actual Yield• Theoretical Yield• Percent Yield
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Chapter 9 Section 1Chapter 9 Section 1Introduction to StoichiometryIntroduction to Stoichiometry
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Definitions
• Composition stoichiometry deals with the mass relationships of elements in compounds.
• Reaction stoichiometry involves the mass relationships between reactants and products in a chemical reaction.
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303p. xx
Sto
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Sto
ichio
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Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Definitions
• A mole ratio is a conversion factor that relates the amounts in moles of any two substances involved in a chemical reactionExample: 2Al2O3(l) 4Al(s) + 3O2(g)
Mole Ratios: 2 mol Al2O3 2 mol Al2O3 4 mol Al
4 mol Al 3 mol O2 3 mol O2
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303p. xx
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Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Mole – Mole ExamplesMg(s) + 2HCl(aq) MgCl2(aq) + H2(g)
• If 2 mol of HCl react, how many moles of H2 are obtained?
• How many moles of Mg will react with 2 mol of HCl?
• If 4 mol of HCl react, how many mol of each product are produced?
• How would you convert from moles of substances to masses?
Chapter 9 Section 1 Intro. Stoichiometry pages 299-303p. xx
Convert
ing f
rom
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onvert
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Chapter 9 Section 1 Intro. Stoichiometry pages 299-303
Section 1 HomeworkSection 1 Homework
Page 301 #1-4
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Chapter 9 Section 2Chapter 9 Section 2Ideal Stoichiometric Ideal Stoichiometric
CalculationsCalculations
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Reactants ProductsMASS OF
SUBSTANCEGIVEN
MASS OF SUBSTANCE
WANTED
MOLES OF SUBSTANCE
GIVEN
MOLES OF SUBSTANCE
WANTED
MOLAR MASS
MOLAR MASS
MOLE RATIO
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Tool BoxTool Box
GRAMSMOLESMOLAR MASS
MOLES MOLESMOLE RATIO
GRAMSmLDENSITY
MOLES PARTICLES6.02x1023
1000 g = 1kg1000 mL = 1L
1000 mg = 1g
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
KgmL mg
g
mgKg
gmL
L
MOLES
MOLES
L
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample ProblemHow many kilograms of ethane are
required to react with excess oxygen to produce 8.70 L of carbon dioxide? The density of carbon dioxide gas at standard temperature is 1.799 g/L.
0.00535 kg
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
KgmL mg
mgKg
gmL
L
MOLES
L
g
MOLES
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
C2H6 (g) + O2 (g) CO2 (g) + H2O (g) + E
gg
MOLES MOLES
8.70L? Kg
L CO2x x x xx
kg C2H6
g CO2 mol CO2mol C2H6 g C2H6
L CO2 g CO2 mol CO2mol C2H6 g C2H6
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
C2H6 (g) + O2 (g) CO2 (g) + H2O (g) + E
gg
MOLES MOLES
8.70L? Kg
L CO2x x x xx
kg C2H6g CO2 mol CO2mol C2H6 g C2H6
L CO2 g CO2 mol CO2mol C2H6 g C2H6
MO
LAR
MA
SS
DEN
SIT
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MO
LAR
RA
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MO
LAR
MA
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10
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g=
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g
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 306In photosynthesis, plants use energy from the sun
to produce glucose, C6H12O6, and oxygen from the reaction of carbon dioxide and water.
What mass, in grams, of glucose is produced when 3.00 mol of water react with carbon dioxide?
90.1 g C6H12O6
mol-mass
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 310Tin (II) fluoride, SnF2, is used in some
toothpastes. It is made by the reaction of tin with hydrogen fluoride according to the following equation.Sn(s) + 2HF(g) SnF2(s) + H2(g)
How many grams of SnF2 are produced from the reaction of 30.00 g HF with Sn?
117.5 g SnF2
mass-mass.
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 305In a spacecraft, the carbon dioxide exhaled by
astronauts can be removed by its reaction with lithium hydroxide, LiOH, according to the following chemical equation.
CO2(g) + 2LiOH(s) Li2CO3(s) + H2O(l)
How many moles of lithium hydroxide are required to react with 20 mol CO2, the average amount exhaled by a person each day?
40 mol LiOHmol-mol
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 309The first step in the industrial manufacture
of nitric acid is the catalytic oxidation of ammonia.NH3(g) + O2(g) NO(g) + H2O(g) (unbalanced)
The reaction is run using 824 g NH3 and excess oxygen.a. How many moles of NO are formed?b. How many moles of H2O are formed?48.4mol NO; 72.5 mol
H2O mass-mol
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
ProblemMagnesium burns in oxygen to produce
magnesium oxide. How many grams magnesium will burn in the presence of 189 mL of oxygen? The density of oxygen is 1.429g/L.
0.410 g Mg
mL-g
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
ProblemLimestone, CaCO3, can be decomposed with
heat to form lime, CaO, and carbon dioxide. How many moles of lime would be formed from the decomposition of 20.1 kilograms of limestone?
201 moles CaO
Kg-mol.
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Section 2 HomeworkSection 2 Homework
Page 311 #1-5
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Section 2 HomeworkSection 2 HomeworkProblem BankProblem Bank
Page 890-892 #176, 177, 179, 180, 184, 187, 190,
191, 192, 194, 196
Chapter 9 Section 3 Limiting Reactant pages 312-318
Chapter 9 Section 3Chapter 9 Section 3Limiting Reactant and Percent Limiting Reactant and Percent
YieldYield
Chapter 9 Section 3 Limiting Reactant pages 312-318
Definitions• The limiting reactant is the reactant
that limits the amount of the other reactant that can combine and the amount of product that can form in a chemical reaction.
• The excess reactant is the substance that is not used up completely in a reaction.
Chapter 9 Section 3 Limiting Reactant pages 312-318
S’mores• Given the bag o’ reactants find the number of
s’mores you could produce if the balanced equation is
• 2 Tg + 1 Mm 1 Sm
• Tg = Teddy Graham
• Mm = Minimarshmallow
• Sm = S’more
Chapter 9 Section 3 Limiting Reactant pages 312-318
S’mores• What is the limiting reactant?
• What is the reactant in excess?
• What is the amount in excess ?
• What is the theoretical yield?
• What is the actual yield?
• What is the percent yield?
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 313Silicon dioxide (quartz) is usually quite
unreactive but reacts readily with hydrogen fluoride according to the following equation.SiO2(s) + 4HF(g) SiF4(g) + 2H2O(l)
If 6.0 mol HF is added to 4.5 mol SiO2, which is the limiting reactant?
HF
mol & mol limiting
Chapter 9 Section 3 Limiting Reactant pages 312-318
ProblemI need a problem that requires them to answer
these questions
a.Which compound is the limiting reactant?
b.What is the theoretical yield of product?
c.What is the reactant in excess, and how much remains after the reaction is completed?
8.940 x 1023 molecules
mass & mass, limiting, actual
Chapter 9 Section 3 Limiting Reactant pages 312-318
ProblemI need another problem that requires them to
answer these questions
a.Which compound is the limiting reactant?
b.What is the theoretical yield of product?
c.What is the reactant in excess, and how much remains after the reaction is completed?
8.940 x 1023 molecules
mass & mass, limiting, actual
Chapter 9 Section 3 Limiting Reactant pages 312-318p. xx
Lim
itin
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Lim
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Chapter 9 Section 3 Limiting Reactant pages 312-318
Section 3 HomeworkSection 3 Homework
Page 318 #1 & 2
Chapter 9 Section 3 Limiting Reactant pages 312-318
Definitions• The theoretical yield is the maximum
amount of product that can be produced from a give amount of reactant.
• The actual yield is the measured amount of product obtained from a reaction.
• The percentage yield is the ratio of the actual yield to the theoretical yield, multiplied by 100.
Chapter 9 Section 3 Limiting Reactant pages 312-318p. xx
Perc
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Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
Sample Problem p. 317Chlorobenzene, C6H5Cl, is used in the
production of many important chemicals, such as aspirin, dyes, and disinfectants. One industrial method of preparing chlorobenzene is to react benzene, C6H6, with chlorine, as represented by the following equation.
C6H6 (l) + Cl2 (g) C6H5Cl (l) + HCl (g)
When 36.8 g C6H6 react with an excess of Cl2, the actual yield of C6H5Cl is 38.8 g.
What is the percentage yield of C6H5Cl?
73.2%mass-mass percent
Chapter 9 Section 3 Limiting Reactant pages 312-318
ProblemHydrogen sulfide gas can be formed by the action
of HCl and FeS, forming FeCl2 as product. What is the theoretical yield in molecules of hydrogen sulfide if 130.5 g of FeS are mixed with 150.0 g of HCl? If the percent yield in the lab is 93.6% what is the actual yield?
8.940 x 1023 molecules
mass & mass, limiting, actual
Chapter 9 Section 2 Ideal Stoichiometry pages 304-311
ProblemBenzene, C6H6, is reacted with bromine, Br2, to produce bromobenzene, C6H5Br, and hydrogen bromide, HBr, as shown below. When 40.0 g of benzene are reacted with 95.0 g of bromine, 65.0 g of bromobenzene is produced.
C6H6 + Br2 C6H5Br + HBr
a.Which compound is the limiting reactant?
b.What is the theoretical yield of bromobenzene?
c.What is the reactant in excess, and how much remains after the reaction is completed?
d.What is the percentage yield?Benzene, 80.4g, Br2 13.2g, 80.8%
Chapter 9 Section 3 Limiting Reactant pages 312-318
Molarity• Molarity measures the concentration of
solutions. (aq)
• Molarity = moles / liter
3M =
3 mol1 L
Chapter 9 Section 3 Limiting Reactant pages 312-318
ProblemWhen 20.0 mL of 0.90M solution of lithium nitrate
and 15.0 mL of 0.40M solution of calcium phosphate react, a precipitate is formed. The mass of the precipitate produced in the lab is 0.66 grams. What is the reactant in excess, the limiting reactant, the amount in excess, the theoretical yield and the percent yield.
0.69 grams theo.
Chapter 9 Section 3 Limiting Reactant pages 312-318
Section 3 HomeworkSection 3 HomeworkProblem BankProblem Bank
Page 892-894 #201, 208, 214, 217, 219, 223, 226,
229, 232