CHAPTER 11 Stoichiometry 11.1 Analyzing a Chemical Reaction.
-
Upload
russell-carr -
Category
Documents
-
view
223 -
download
1
Transcript of CHAPTER 11 Stoichiometry 11.1 Analyzing a Chemical Reaction.
CHAPTER 11
Stoichiometry
11.1 Analyzing a Chemical Reaction
2 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories… 2CO(g) + O2(g) → 2CO2(g)
3 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
… and stories can be put into different categories
Nonfiction
Science fiction
Adventure
Romance
History
Psychology
Children’s literature
…
2CO(g) + O2(g) → 2CO2(g)
4 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
… and stories can be put into different categories
Nonfiction
Science fiction
Adventure
Romance
History
Psychology
Children’s literature
…
Synthesis / Decomposition
Single / Double replacement
Precipitate reaction
Polymerization reaction
2CO(g) + O2(g) → 2CO2(g)
5 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
… and stories can be put into different categories
Synthesis / Decomposition
Single / Double replacement
Precipitate reaction
Polymerization reaction
2CO(g) + O2(g) → 2CO2(g)
6 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
But what exactly do they tell us?
2CO(g) + O2(g) 2CO2(g)
7 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
But what exactly do they tell us?
2CO(g) + O2(g) 2CO2(g)
They tell us what compounds we start with:Carbon monoxide (CO) gas
Oxygen (O2) gas
8 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
But what exactly do they tell us?
2CO(g) + O2(g) 2CO2(g)
They tell us what compounds we start with:Carbon monoxide (CO) gas
Oxygen (O2) gas
what compounds are formed:Carbon dioxide (CO2) gas
9 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
What else do they tell us?
2CO(g) + O2(g) 2CO2(g)
10 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
What else do they tell us?
2CO(g) + O2(g) 2CO2(g)
2 CO molecules 2 CO2 molecules1 O2 molecules
They tell us how much of each compound is involved
11 11.1 Analyzing a Chemical Reaction
Chemical equations tell stories…
What else do they tell us?
2CO(g) + O2(g) 2CO2(g)
stoichiometry: the study of the amounts of substances involved in a chemical reaction.
2 CO molecules 2 CO2 molecules1 O2 molecules
They tell us how much of each compound is involved
12 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 CO molecules2 dozen CO molecules
1 O2 molecules1 dozen O2 molecules
2 CO2 molecules2 dozen CO2 molecules
13 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 CO molecules2 dozen CO molecules2 moles CO molecules
1 O2 molecules1 dozen O2 molecules
1 mole O2 molecules
2 CO2 molecules2 dozen CO2 molecules2 moles CO2 molecules
14 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 CO molecules2 dozen CO molecules2 moles CO molecules
2 x (6.022 x 1023) CO molecules
1 O2 molecules1 dozen O2 molecules
1 mole O2 molecules(1 x) 6.022 x 1023 O2 molecules
2 CO2 molecules2 dozen CO2 molecules2 moles CO2 molecules
2 x (6.022 x 1023) CO2 molecules
15 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 moles
CO molecules
1 mole
O2 molecules
2 moles
CO2 molecules
Number of moles is not conserved
Is that okay?
≠+
16 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 moles
CO molecules
1 mole
O2 molecules
2 moles
CO2 molecules
Number of moles is not conserved
Is that okay?
Yes, as long as the chemical equation is balanced!
≠+
17 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 C atoms
2 O atoms2 O atoms
2 C atoms
4 O atoms
Number of atoms is
conserved
This chemical equation is balanced
=
=+
18 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 moles
CO molecules
1 mole
O2 molecules
2 moles
CO2 molecules
This chemical equation is balanced
The coefficients are correct
Coefficients
19 11.1 Analyzing a Chemical Reaction
2CO(g) + O2(g) 2CO2(g)
2 moles
CO molecules
1 mole
O2 molecules
2 moles
CO2 molecules
This chemical equation is balanced
The coefficients are correct
CoefficientsThese are important!
20 11.1 Analyzing a Chemical Reaction
Coefficients are important
1 bagcake mix
+ 3 eggs + ¼ cup oil + 1 cup water 1 batch cupcakes
21 11.1 Analyzing a Chemical Reaction
Coefficients are important
+ 3 eggs + ¼ cup oil + 1 cup water 1 batch cupcakes1 bagcake mix
I need ¼ cup of oil to make 1 batch of cupcakes
22 11.1 Analyzing a Chemical Reaction
Coefficients are important
+ 3 eggs + ¼ cup oil + 1 cup water 1 batch cupcakes1 bagcake mix
1 14114
cup oil batch cupcakesor
batch cupcakes cup oilWrite as a ratio:
23 11.1 Analyzing a Chemical Reaction
Coefficients are important
+ 3 eggs + ¼ cup oil + 1 cup water 1 batch cupcakes1 bagcake mix
I need 1 cup of oil to make 4 batches of cupcakes
24 11.1 Analyzing a Chemical Reaction
Write as a ratio:
Coefficients are important
+ 3 eggs + ¼ cup oil + 1 cup water 1 batch cupcakes1 bagcake mix
1 4
4 1
cup oil batches cupcakesor
batches cupcakes cup oil
25 11.1 Analyzing a Chemical Reaction
Coefficients are important
Fermentation of sugar (glucose) into alcohol:
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
26 11.1 Analyzing a Chemical Reaction
Coefficients are important
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
27 11.1 Analyzing a Chemical Reaction
Coefficients are important
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
1 moles
3 molesglucose will yield
2 moles
6 moles
ethanol/ carbon dioxide
x 3
28 11.1 Analyzing a Chemical Reaction
Coefficients are important
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
1 moles
3 moles
7.5 moles
glucose will yield
2 moles
6 moles
15 moles
ethanol/ carbon dioxide
x 7.5x 3
29 11.1 Analyzing a Chemical Reaction
Coefficients are important
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
7.5C6H12O6(aq) 15C2H5OH(aq) + 15CO2(g)
7.5 molesglucose
15 molesethanol
15 molescarbon dioxide
You MUST multiply all the coefficients by the same number
30 11.1 Analyzing a Chemical Reaction
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
Write as a ratio: 1 2
2 1
mole glucose moles ethanol
moles ethanol mole glucose
These are stoichiometric equivalents
31 11.1 Analyzing a Chemical Reaction
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
Write as a ratio: 1 2
2 1
mole glucose moles ethanol
moles ethanol mole glucose
mole ratio: a ratio comparison between substances in a balanced equation. It is obtained from the coefficients in the balanced equation.
32 11.1 Analyzing a Chemical Reaction11.1 Analyzing a Chemical Reaction
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
Fermentation of sugar (glucose) into alcohol:
1 moleglucose
2 molesethanol
2 molescarbon dioxide
1 2
2 1
mole glucose moles ethanol
moles ethanol mole glucose
2
2
21
2 1
moles COmole glucose
moles CO mole glucose
2
2
22
2 2
moles COmoles ethanol
moles CO moles ethanol
mole ratios for this
chemical equation
Mole ratios
33 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
Compare the reactant CO to the product CH3OH.
carbon monoxide
hydrogen methanol
34 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
3
3
11
1 1
molemole
m
CH
ol
OHCO
e mCH OH Oole C
Compare the reactant CO to the product CH3OH.
35 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
36 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
Asked: moles of H2
Given: moles of CH3OH
37 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
Asked: moles of H2
Given: moles of CH3OH
Write a mole ratio between H2 and CH3OH
Write moles of H2 (asked) “on top”
38 11.1 Analyzing a Chemical Reaction
2
33
25
1
moles H
mole CH Omoles CH H
HO
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
“on top”Asked: moles of H2Write a mole ratio between H2 and CH3OH
Write moles of H2 (asked) “on top”
39 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
2
33
25
1
moles H
mole CH Omoles CH H
HO
Given: moles of CH3OH
40 11.1 Analyzing a Chemical Reaction
CO(g) + 2H2(g) CH3OH(l)
Mole ratios
Consider the following equation:
carbon monoxide
hydrogen methanol
If the reaction produces 5 moles of CH3OH, how many moles of H2 are consumed?
2
323
25
110
moles Hmoles CH OH
molmo
eCH OH
Hles
Asked: moles of H2
41 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
42 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
43 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
Write a mole ratio between AlCl3 and Cl2
Write moles of AlCl3 (asked) “on top”
44 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
23
233.3
25
3moles C
moles AlCl
moles Cll moles AlCl
Asked: moles AlCl3
Given: moles Cl2“on top”
Write a mole ratio between AlCl3 and Cl2
Write moles of AlCl3 (asked) “on top”
45 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
23
233.3
25
3moles C
moles AlCl
moles Cmoll
les AlCl
46 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
23
233.3
25
3moles C
moles AlCl
moles Cmoll
les AlCl
units cancel out
47 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
32
23
2
33.35
moles AlClmoles Cl
molmoles A
es Cl
llC
units cancel out
48 11.1 Analyzing a Chemical Reaction
A mixture of aluminum metal and chlorine gas reacts to form aluminum chloride (AlCl3): 2Al(s) + 3Cl2(g) → 2AlCl3(s). How many moles of aluminum chloride will form when 5 moles of chlorine gas react with excess aluminum metal?
Asked: moles AlCl3
Given: moles Cl2
32
23
2
33.35
moles AlClmoles Cl
molmoles A
es Cl
llC
Answer: 3.3 moles of AlCl3 are produced.
49 11.1 Analyzing a Chemical Reaction
There is no scale that measures in moles!
How do you convert from moles to grams?
The mass of 1 mole of Al is not the same as the mass of 1 mole of Cl2.
How do you convert from grams of Al to grams of Cl2?
50 11.1 Analyzing a Chemical Reaction
There is no scale that measures in moles!
How do you convert from moles to grams?
The mass of 1 mole of Al is not the same as the mass of 1 mole of Cl2.
How do you convert from grams of Al to grams of Cl2?
By using the molar mass (g/mole)
By using the molar mass (g/mole) and mole ratios
51 11.1 Analyzing a Chemical Reaction
Process for calculating grams from grams given
52 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Calcium carbonate (CaCO3) is present in rocks, eggshells and most seashells.
CaCO3 decomposes when it is heated.
53 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios molar mass of CaCO3 = 40.078 + 12.011 + (15.999 x 3) = 100.0 g/molemolar mass of CO2 = 12.011 + (15.999 x 2) = 44.01 g/mole
Strategy:
54 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
45.0 g CaCO3
55 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
33 3
3
145 0.45
100.09
mole CaCOg CaCO moles CaCO
g CaCO
45.0 g CaCO3 0.45 moles CaCO3
56 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
0.45 moles CaCO3
57 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
23 2
3
10.45 0.45
1
mole COmoles CaCO moles CO
mole CaCO
0.45 moles CaCO3 0.45 moles CO2
58 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
0.45 moles CO2
59 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
22
22
44.010.45
119.8
g COmoles CO
mole COg CO
0.45 moles CO2 19.8 g CO2
60 11.1 Analyzing a Chemical Reaction
If 45.0 g of calcium carbonate (CaCO3) decomposes in the reaction CaCO3(s) → CaO(s) + CO2(g), how many grams of CO2 are produced?
Asked: grams of CO2 Given: grams of CaCO3
Relationships: mole ratios, molar mass of CaCO3 = 100.0 g/molemolar mass of CO2 = 44.01 g/mole
0.45 moles CO2 19.8 g CO245 g CaCO3 0.45 moles CaCO3
Answer: 19.8 g of CO2 are produced.
61 11.1 Analyzing a Chemical Reaction
C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g)
1 moleglucose
2 molesethanol
2 molescarbon dioxide
1 2
2 1
mole glucose moles ethanol
moles ethanol mole glucose
These are stoichiometric equivalents
Mole ratios: