Download CHAPTER 11 CHEMICAL REACTIONS

CHAPTER 11
CHEMICAL
REACTIONS
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INTRODUCTION
Chemical changes are a result of chemical reactions. All
chemical reactions involve a change in substances and a
change in energy. Neither matter nor energy is created
or destroyed in a chemical reaction---only changed. There
are so many chemical reactions that it is helpful to
classify them into types. These will be the topic of this
chapter.
READING ACTIVITY Pages:320-329
Chapter 11: Chemical Reactions
Describing Chemical Reactions
Section: 11.1
Key Concepts: By the end of this section you
will be able to:
1. write a Word Equation.
2. write a Skeleton Equation
3. write a balanced chemical equation.
VOCABULARY
1) Chemical equation - ___________________
______________________________________
4
2) Skeleton Equation - _____________________
________________________________________________
________________________________________________
3) Catalyst - __________________________________
________________________________________________
________________________________________________
________________________________________________
4) Coefficients - ________________________________
________________________________________________________________________
________________________________________________________________________
5) Balanced equation - _________________________
________________________________________________
________________________________________________
________________
A- Writing Chemical Equations
Notes:
1 . In a chemical reaction one or more
substances (_________ ) change into one or
more new substances (____________ ) .
5
2. A quick shorthand method known as a
________ _________ is used to convey as
much information as possible about what
happened in the chemical reaction.
3. Word Equations
a. __________________  PRODUCTS
----b. The arrow in the equation means _____,
_________ or ______________________.
c. When reacting Iron and oxygen to
produce rust (iron(III)oxide) you would
write
_____________________________________
d. To write a word equation:'
i.Write the names of the ____________to
the left of the arrows.
ii. Write the names of the
the right of the arrow.
6
to
e. The reaction of hydrogen peroxide
decomposing into oxygen and hydrogen
would be written as follows:
Hydrogen Peroxide  water + oxygen.
f. In the above reaction
are
produced. This lets us know a gas is
being given off.
g. When natural gas (methane) is burned
on your stove or Bunsen burner the
reaction is written as follows:
_________________________________________
Checkpoint: What does the arrow () in a word equation mean?
_____________________________________________
_____________________________________________
_____________________________________________
7
4. Chemical Equations
a. A chemical equation is a
.
(on the left) are
b.The
connected to the
right) by an
(on the
.
c. Write the chemical equation for rusting
below.
_______________________________________
d. Equations that show just the formulas of
the reactants and products are called
______________ ________________ .
e. The first step in writing a chemical
equation is to write a skeleton
equation.
i. Write the formulas _______________ _
____________.
8
.
ii. To add more information to the
equation you can indicate the
________________ of substances by
putting a __________________
1. (s)
2. (g)
3.(1)
4. (aq)
Add the physical states to the equation:
Practice Problems: from pg 324
1 .Write a sentence that describes this chemical reaction:
Na((s) + H2O (l)  NaOH (aq) + H2 (g)
2. Sulfur burns in oxygen to form sulfur dioxide.
Write a skeleton equation for
this chemical reaction. Include appropriate symbols from Table 11.1.
________________________________________
Things I don't understand:
9
B- Balancing Chemical Equations
Notes:
1. Using the equation for the synthesis of water
the parts of the equation are shown below.
4.
3.22
2H2 +
COEFFICIENTS
O2

CHEMICAL
FORMULA
2H2O
SUBSCRIPT
Coefficient- _____________________________________
_________________________________________________
_______________________ ______________________ _
Chemical formula- _______________________________
________________________________________
Subscript- ___________________________________
___________________________________ ___________ _
In a ________________________________, there are the
same numbers at each atom on both sides of the
____________sign. For example:'
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S(S) + 02 (g)  S02 (g)
S=1
0=2
S=1
0=2
In the above equation, there is ______ sulfur atom
on the left of the arrow and
sulfur atom on the
right of the arrow. Also there are 2 __________ atoms
on the left side and 2 oxygen atoms on the right. The
amounts of oxygen and sulfur are __ on both sides of
the arrow.
In the equation below the elements are not
equal on both sides. Let’s count them up to see how
many we have.
H 2 + 02  H 2 0
H= _____
O= _____
H= ____
O= ____
There are ___ hydrogen on the left and ___ on
the right of the arrow.
There are ___ oxygen atoms on the right of
the arrow and only _______on the left. We need
to
11
6.
5.
make them equal. To do this I can only add
_________ (numbers in front ) to the equation.
I need___ 0 on the right of the arrow because I
have 2 on the left of the arrow. I can place a
coefficient of 2 in front of the ____ on the right of the
arrow. I then multiply the coefficient of 2 by the
subscript of 2 in the hydrogen. This gives
me___hydrogen. If I multiply the coefficient 2 by the
subscript of the 0, which is ___ ,I have a total of 2
oxygen on both sides. They are equal but now my
hydrogen are not equal.
H 2 + 02  2 H 20
H= _____
O= __2___
H= 2
O= __2__
I need to place a 2 in front of the H2 on the
left of the arrow. This will give me 4 hydrogen.
Now everything on the left of the arrow is equal to
everything on the right of the arrow.
2H2 + 02  2 H20
H= _____
O= __2___
H= 4
O= __2__
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The equation is balanced !
Rules for Writing and Balancing Equations
1. Determine the correct formulas and physical states for
all the ____________ and ________________.
2. Write the _____________________ with the formulas
for the reactants on the left and formulas for the
products on the right of a yield sign. If 2 or more
reactants or products are involved, separate their
formulas with plus signs.
3.Count the number
of each element
in the reactants and products. Count a polyatomic ion
as a single unit if it appears unchanged on both sides
of the equation.
4. Balance the number of atoms of the elements on the
two sides of the equation by placing _____________ in
front of the formulas. When no coefficients written, it is
assumed to be 1. Begin by balancing elements that
appear only once on each side of the equation. Never
balance an equation by changing the _________ _
in a chemical formula. Each substance has only one
correct formula.
S. Check each atom or polyatomic ion to be sure the
equation is
.
6. Make sure all the coefficients are in the
possible ratio.
13
Checkpoint: What is the Law of Conservation of Mass? (Pg.325)_
Practice Problems (Pg 327)
3. Directions: Balance each equation. 'Place the coefficient on the line to
the left of the formula. Some lines may not be filled in..
a. __ AgN03 + __ H2S  __ Ag2S + __ HN03
4. Directions: Rewrite these word equations as balanced chemical
equations.
a. hydrogen + sulfur  hydrogen sulfide
b. iron (III) chloride + calcium hydroxide 
iron (III) hydroxide + calcium chloride
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11 . 1 Section Assessment Questions: (pg 329)
7. How do you write a word equation?
8.How do you write a skeleton equation?
9. Describe the steps in writing a balanced chemical
equation.
1 O. Write the skeleton equations for these reactions.
a. heating copper(lI) sulfide in the presence of diatomic
oxygen produces pure copper and sulfur dioxide gas.
b. When heated, baking soda (sodium hydrogen
carbonate)decomposes to form the products sodium
carbonate, carbon dioxide and water.
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Write and balance equations for the following
reactions.
a. Iron metal and chlorine gas react to form solid iron
(III) chloride.
b. solid aluminum carbonate decomposes to form
solid aluminum oxide and carbon dioxide gas.
c. Solid magnesium reacts with aqueous silver
nitrate to form solid silver and aqueous magnesium
nitrate.
2. Balance the following equations.
a-
S02 +
b. __Fe203 +
02 
H2 
S03
Fe +
H20
c. ___ P + ____ 02  ____ P4010
d. _____ Al+ ____N2 _____ AlN
Things I don't understand:
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
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EXERCISE 1:
SKELETON EQUA TIONS
DIRECTIONS: Write the chemical equation for each of the following skeleton equations.
1. hydrogen reacts with oxygen to produce water
2. potassium chloride reacts with aluminum to produce potassium and aluminum chloride
3. calcium reacts with sodium hydroxide to produce sodium and calcium hydroxide
4. calcium carbonate decomposes yielding calcium oxide and carbon dioxide
5. Hydrogen chloride reacts with sodium hydroxide to produce water and sodium chloride
6. Copper reacts with hydrogen chloride to produce copper (II)chloride and hydrogen gas
7. methane gas (CH4) burns in oxygen to produce carbon dioxide and water
8. chlorine and sodium hydroxide react to produce sodium chloride and sodium hypochlorite
and water
9. calcium reacts with water to produce calcium hydroxide and water
10. calcium sulfate and sodium carbonate react to produce calcium carbonate and sodium
sulfate
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Exercise 2:
Balancing Equations
Directions: Balance the following equations. After the equation is balanced, add the
coejJiecients and place the total on the line to the right. Blank lines count as 1.
TOTAL:
_____________
2.
TOTAL:
_
3.
TOTAL:
4.
HCl+
NaOH 
NaCl+
H 20
TOTAL:
5.
KOH +
_HBr 
KBr +
Mg +
Cl2 
MgCI2
TOTAL:
_
18
_
H20
TOTAL:
6.
_
_
TYPES OF CHEMICAL REACTIONS
Section: 11.2
Key Concepts: By the end of this section you will be
able to:
1 . identify the five general types of reactions
2. Predict products for the five general types of
reactions.
VOCABULARY
Combination Reaction- ________________________
___________________________________________
___________________________________________
EXAMPLE:
Decomposition Reaction -
EXAMPLE: ________________________________________ _
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Single-replacement Reaction -
EXAMPLE:
Double-replacement Reaction-
EXAMPLE:
Combustion Reaction -
EXAMPLE:
Activity Series
-
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Checkpoint: What are the products of the combustion of a
hydrocarbon?(pg.336) _____________________________________
SECTION 11.2 TYPES OF CHEMICAL REACTIONS
(pages 330-339)
This section explains how to identify a reaction as a combination, decomposition,
single-replacement, double-replacement, or combustion reaction. It also describes
how to predict the products of each type of reaction.
Classifying Reactions (page 330)
1.There are
reactions.
____ general types of chemical
2. Complete the diagram of a combination reaction. Which
characteristic of this type of reaction is shown in the diagram?
+
2Mg(s)
Magnesium
2MgO(s)
+
Magnesium oxide
3. Is the following sentence true or false? The product of a combination
reaction is always a molecular compound.
_
4. Circle the letter of each set of reactants that can produce more than one
product.
a. two
nonmetals
c. a transition metal and a
nonmetal
b. a Group A metal and a
nonmetal
d. two
metals
5. Look at Figure 11.6 on page 332. Which characteristics of a
decomposition reaction are shown in the diagram?
21
Name ________________________ _
Date ________________ _
Class _________________
CHAPTER 11, Chemical Reactions (continued)
6.Rapid decomposition reactions can cause
of the formation of gaseous products and heat.
as a result
7.Most decomposition reactions require the addition of _______________ _
in the form of heat, light, or electricity.
8.Complete the diagram of a single replacement reaction. Which
characteristics of this type of reaction are shown in the diagram?
+
2KOH(aq)
Potassium hydroxide
2K(s)
Potassium
+ H2(g)
Hydrogen
9. Using Table 11.2 on page 333, state whether the following
combinations will produce a reaction or no reaction.
a.Ag(s) + HCl(aq) _____________
b.Cu(s) + AgN03(aq) ________________
10. Look at Figure 11.8 on page 335. Which characteristics of a
doublereplacement reaction are shown in the diagram?
11. When solutions of ionic compounds are mixed, what three
circumstances may indicate that a double-replacement reaction has
occurred?
a. ___________________________________________________________________ _
b. ____________________________________________________ _
c. ________________________________________________________
12. Look at the diagram of a combustion reaction in Figure 11.9 on page
336. Which characteristics of this type of reaction are shown in the
diagram?
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2
0
Name __________________________
Date _________________
Class ________________ _
13. Is the following sentence true or false? Hydrocarbons, compounds of
hydrogen and carbon, are often the reactants in combustion reactions.
14. Circle the letter of each compound that can be produced by
combustion reactions.
a. oxygen
b. carbon
dioxide
c.water
d.glucose
23
Predicting the Products of a Chemical Reaction
(pages 337-339)
15. Classify the reaction in each of the following equations.
a.BaClz(aq) + KZCr04(aq) ~ BaCr04(s) + 2KCI (aq) _____________ _____
b.Si(s) + 2Clz(g) ~ SiCI4(l) __________________ _
c. 2CsHs(l) + 150z(g) ~ 6HzO(l) + 12COz(g) ____ _______________ _
16. Use Figure 11.10 on page 339. The equation for the
combustion of pentane is C5H1Z + 80z ~ 5COz + 6HzO. What
numbers in this equation are represented by x and y in the
general equation
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Types of Reactions
Directions: State whether each of the following equations represents a
combination (e), decomposition (0), single replacement (SR), or double
replacement (OR) reaction or combustion (CR) reaction.
1. CO2  C + O2
2.NaCI + AgN03  NaN03 + AgCI
3. S + CI2  SCI2
4. BaCI2 + 2 NaOH  2NaCI +
Ba(OH)2
5.Zn + CuS04  ZnS04+ Cu
6. CH4  C + 2H2
7. Mg + 2HCI  MgCI2 + H2
8. 2KI + Br2
9. 2NaF

 2KBr + 12
2Na + F2
10. Si + O2 Si02
11. 2Nal + Pb(N03)2  2NaN03 + Pbl2
12. Li3 P04  3 Li + P + 202
13. CS2 + 2F2  CF4 + 2S
25
SECTION 11.3
Reactions in Aqueous Solution
Key Concepts: By the end of this section you
will be able to:
1 - write and describe a net ionic equation.
2 - Predict the formation of a precipitate in a
double-replacement reaction.
VOCABULARY
1) Net Ionic Equation - ___________________
______________________________________
2) Complete Ionic Equation - _____________________
________________________________________________
________________________________________________
3) spectator ion ________________________________
________________________________________________
________________________________________________
________________________________________________
26
SECTION 11.3 REACTIONS IN AQUEOUS SOLUTION
(pages 342-344)
This section explains how to write and balance net ionic equations. It also
describes the use of solubility rules to predict the formation of precipitates in
double-replacement reactions.
~ Net Ionic Equations (pages 342-343)
1.Many important chemical reactions take place in _____
2.An equation that shows dissolved ionic compounds as
their free ions is called a(n)
3.Is the following sentence true or false? A spectator
ion is not directly involved
in a reaction.
4.What is a net ionic equation?
27
5. Circle the letter of each sentence that is true
about ionic equations.
a. A complete ionic equation shows only the ions involved in the
reaction.
b. Spectator ions are left out of a net ionic
equation.
c.Atoms do not need to be balanced in
an ionic equation. d. Ionic charges must
be balanced in a net ionic equation.
6.Write the balanced net ionic equation for this
reaction:
Pb(N03Maq) + Kl(aq) ~ PbI2(s) + KN03(aq).
Show your work.
~ Predicting the Formation of a Precipitate
(page 344)
7.What determines whether a precipitate forms when
two solutions of ionic compounds are mixed?
8. Use Table 11.3 on page 344 to predict whether the
following compounds are soluble or insoluble.
a. Fe(OH)3
b. NaOH
c.Ca(Cl03)2 _____________ _
d. HgS04
28
Reaction Prediction
Name:
________________
Directions:
Predict the products and write balanced chemical equations.
+ ____ Na 
1.
____ BaCI2
2.
____HCI
3.
____AgN03 + ____Na3P04
4.
____NaOH + ____Fe(N03)3
5.
___02 + ____Na 
6.
7.
____NiS04 + ____ KOH
____Fe + ____ AgCI 
Directions:
Write chemical equations for the following predicting the products of the reactions.
Don't forget to BALANCE!
1. silver nitrate+ potassium iodide
2. Copper (II) sulfate + sodium 
3. Cobalt chloride + sodium hydroxide
4. Nickel (II) chloride 
5. Copper + sulfurous acid (H2S03 )
6. Magnesium oxide + water
7. Barium chloride (heated) 
8. Manganese (IV) chloride + oxygen gas 
9. Ammonium sulfate + lead (II) 
10. Sulfur trioxide + water ~
29
Name _______________________ _
Date ________________ _
Class ________________ _
PRACTICE PROBLEMS
2. Sulfur burns in oxygen to form sulfur dioxide. Write a skeleton
equation for this chemical reaction. Include appropriate
symbols from table 11.1.
Analyze
Step 1. Identify the relevant concepts.
Write the formula for each reactant and each product. Include
the common STP state of each substance.
Reactants
Products
Solve
Step 2. Write the skeleton equation using + between reactants
on the left hand side and  to separate reactants from products:
Do you remember?
What are the indications of chemical reactions?
_________________________________________________________
_________________________________________________________
_________________________________________________________
_________________________________________________________
30
Here are some practice problems..
1. __NaCl + __BeF2 --> __NaF + __BeCl2
2. __FeCl3 + __Be3(PO4)2 --> __BeCl2 + __FePO4
3. __AgNO3 + __LiOH --> __AgOH + __LiNO3
4. __CH4 + __O2 --> __CO2 + __H2O
5. __Mg + __Mn2O3 --> __MgO + __Mn
31
Name _______________________ _
Date _______________ _
Class _______________ _
REACTIONS
CHEMICAL
Vocabulary Review
Each clue describes a vocabulary term. Read the clues and write the letters of each term on the lines
provided.
1. Clue: the complete reaction of a hydrocarbon with oxygen to produce carbon dioxide and
water.
------0--2. Clue: a single compound is broken down into two or more products.
-0---0------3. Clue: the equation indicating only those particles that actually take part in a chemical
reaction in an aqueous solution.
0--0-
4. Clue: a substance that speeds up the rate of a chemical reaction.
-0-----5. Clue: the elements or compounds on the left side of a chemical equation.
0-------6. Clue: ions that do not participate in an aqueous chemical reaction.
-0------7. Clue: reaction in which atoms of one element replace the atoms of a second, less reactive,
element in a compound.
----------0
8. Clue: a chemical equation that is consistent with the law of conservation of mass.
------09. Clue: numbers placed in front of chemical symbols or formulas in a chemical reaction.
0----------Write the letters found inside the circles on the lines below. Then unscramble them to find the term
used to describe an insoluble salt.
Scrambled letters:
32
Name ________________________ _
Date _________________ _
Class _______________ _
CHEMICAL REACTIONS
Practice Problems
In your notebook, solve the following problems. Use the 3-step problem-solving
approach you learned in Chapter 1.
SECTION 11.1 DESCRIBING CHEMICAL REACTIONS
1. Write the skeleton equation for the reaction between hydrogen and
oxygen that produces water.
2. Write the skeleton equation for the reaction that produces iron (II)
sulfide from iron and sulfur.
3. Write the skeleton equation representing the heating of magnesium
carbonate to produce solid magnesium oxide and carbon dioxide gas.
4. Write a balanced equation for the production of HCI gas from its
elements.
5. Write a sentence that completely describes the chemical reaction
represented by this balanced equation.
2HCl(aq) + CaC03(s) CO2(g) + CaCl2(aq) + H 2O(l)
6. Write the word equation for the following equation. Write a
sentence fully describing the reaction. Is the equation
correctly balanced? Explain.
2Ag(s) + S(s)  Ag 2S(s)
7. Write a balanced equation representing the formation of aqueous
sulfuric acid from water and sulfur trioxide gas.
8. Write a balanced equation from this word equation.
aqueous silver nitrate + copper metal ~ silver metal + aqueous
copper nitrate
9. Write a balanced equation for the following word equation.
phosphorus + oxygen ~ tetraphosphorous decoxide
SECTION 11.2 TYPES OF CHEMICAL REACTIONS
1. Write a balanced equation representing the reaction of magnesium with
oxygen gas to produce magnesium oxide.
2. Write the balanced equation for the reaction that occurs between
aluminum and fluorine.
3. Write the balanced equation for the production of oxygen gas and
potassium chloride from the decomposition of potassium chlorate.
4. Write the balanced equation for the reaction between hydrochloric acid
and calcium metal. The products are hydrogen gas and calcium chloride.
5. Write the balanced equation for the combustion of propane (C3Ha) to
produce carbon dioxide and water vapor.
6. Write the balanced equation for the reaction between iron (III) chloride
and sodium hydroxide. The products are iron (III) hydroxide and sodium
chloride.
33
Name ________________________ _
Date ________________ _
Class ________________ _
7. Classify each of the reactions in problems 1-6 as to type.
8. Use the activity series of metals (Table 11.2) and your knowledge
of the relative reactivity of the halogens to predict whether the
following reactions will occur. Write balanced equations for those
reactions that do occur.
a.
Br2(s) +
NaCl(aq) 
b.
Ca(s) +
Mg(N03)2 (aq)
c.
K(s) +
H2S04(aq) 
d.
Zn(s) +
NaOH(aq)
SECTION 11.3 REACTIONS IN AQUEOUS SOLUTION
1. Write the net ionic equation for the reaction between aqueous
barium nitrate, Ba(N03lz. and sodium sulfate, NaZS04.
2. Magnesium reacts with HCI to form hydrogen and magnesium
chloride. Write the balanced net ionic equation for this reaction.
3. The double-replacement reaction below results in the formation of
the precipitate lead chloride. Balance the equation and write the
net ionic equation.
Pb(N03)2(aq) + NH4Cl(aq) ~ PbCl2(s) + NH4N03(aq)
4. Identify the precipitate formed when solutions of the
following ionic compounds are mixed. If no precipitate is
formed, write no precipitate.
a. Zn(N03)2 + SnCl2 
b. KCI + AgN03 
c. Cu(N03)2 + Na2S ~
d. Al2(S04)3 + 3Mg(OH)2 
34
2
7
2
C
or
e
T
ea
ch
in
g
R
es
ou
rc
es
NAME:
-----------------Predicting Reaction Products &
Balancing Chemical Equations
Reaction Type
1.
Reactants
C3HS
+
O2
2.
C7H16 +
O2
3.
C2H2
+
O2
4.
C4H1O +
O2
Products
5.
C6H6
+
O2
6.
Mg
+
N2
7.
Na
+
82
8.
Mg
+
O2
9.
AI
+
O2
10.
K
+
P
11.
H3P04
H4P207
+
H2O
12.
HgO
Hg
+
O2
35
13.
H202
H2O
+
O2
+
O2
14.
KCI03
KCI
15.
AU203
Au
16.
Zn
+
HCI
17.
AI
+
FeO
18.
Al
+
HCI
19.
Ca
+
AICh
20.
Fe2(S04)3 +
KOH
21.
AI2(S04)3 +
Ca(OH)2
22.
FeCI3
+
NH40H
23.
BaCI2
+
Ah(S04)3
24.
SrBr2
+
(NH4)2C03
25.
Hg(OH)2 +
H3P04
36
+
O2