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Hemet High  Chemistry
Name:
Pd:
Chapter 8 Homework Packet
Date
Assigned
Date
Due
Assignment
Stamp
All Notes Completed and Attached
____/10 pts
Ch 8.1 pg 274 #1-3
and pg 290 #1-2, 13
Ch 8.2 pg 284 #1-2 and pg 291 #27
(write formulas, balance, & classify)
Balancing Worksheet #1 and #2
Balancing & Classifying Worksheet #3
Ch 8.2 and 8.3 pg 284 #4
and pg 287 #2-3
Types of Reactions Worksheet #1
Types of Reactions Worksheet #2
Ch 8 Review Worksheet
Due end of Class on Tuesday!
Final Packet
Test is
___/90
Hemet High • Chemistry
8 ● Chemical Equations and Reactions
NOTES
Section 1: Balancing Equations
Indications of a Chemical Reaction

Evolution of energy as _________ and _________.

Production of a ________

Formation of a __________________

__________ Change
Characteristics of Chemical Equations

The equation must represent known ____________.

The equation must contain the correct ___________ for the reactants and products.

The law of conservation of _________ must be satisfied.
Chemical Reactions
Chemical equations give information in two major areas:
1. ______________ and ______________ of the reaction.
2. __________________ of a balanced chemical equation tell us the ___________ of the
substances involved.
Example of a Balanced Chemical Equation: 2H2 (g) + O2 (g)  2H2O (g)
Review: Reactants are on the _______ side of the arrow, and the products are on the __________
side. The arrow means “____________” or “to produce”.
Common Symbols used in Chemical Equations: See table 2 on page 266
Balancing Chemical Equations
Why do you have to balance a chemical equation?
 Law of Conservation of Matter (Mass): Matter is neither created nor destroyed in chemical
reactions.
 During a chemical reaction, atoms are either ____________, separated, or rearranged. The
______________ and type of each atom stays the same.
How do you balance a chemical equation?
 Coefficients are placed in ________ of the substances involved in the chemical reaction to get
the same _________ of atoms of each element on both sides of the equation.
Rules for Balancing Chemical Equations
(1) Coefficients can only be placed in __________ of a chemical formula.
Practice Problems: How many atoms of each type are indicated in the following compounds?
(a) 2 (NH4)3PO4
N=
H=
P=
O=
(b) 4 KC2H3O2
K=
C=
H=
O=
(c) 3 Ca(NO3)2
Ca= N=
O=
(2) You cannot change a ________________!!
Example :
H2 + O2  H2O
To balance oxygen, you cannot change water’s formula to __________!!
(3) You cannot place the coefficient in the __________ of a formula!!
Example :
Al + N2 
AlN
To balance nitrogen, you cannot put a 2 in the middle to make _______!
(4) Reduce the coefficients to the simplest ___________ ____________ ratio.
Example:
H2 + O2  H2O can be reduced to… H2 + O2  H2O
(5) Get rid of any ___________! Coefficients must be ___________ numbers! You can’t have a
____________ of a molecule or atom!
Example:
1 H2 + ½ O2  1 H2O
changes to…
H2 + O2  H2O
Balancing Equations: “Helpful Hints”
a) Balance elements that appear in more than one compound __________
(NH4)2CO3 
NH3 + CO2 + H2O
b) Balance __________________ as though they are one item as long as the ion stays together as a
group on each side of the arrow.
Al + CuSO4  Al2(SO4)3 + Cu
c) If you can’t seem to get it balanced, ____________ and begin with a different element the next
time, or put a “ _____” somewhere and then try again.
Li + H2O 
LiOH + H2
• This is what I’ll constantly be telling you to do if you are stuck and you need my help... “Pick an
element to balance. How many are on the left side? How many are on the right side?
___________!!!
Fe(OH)3 
Fe2O3 + H2O
Example
• Aluminum is a good choice for outdoor furniture because it reacts with oxygen in the air to form a
thin protective coat of aluminum oxide. Write word, formula, and chemical equations for this
reaction.
Word:
Formula:
Chemical Equation:
Section 2: Five Types of Reactions
General Types of Reactions
1) ________________: A reaction that breaks apart _________________ into simpler substances,
(usually two elements or an element and a smaller compound.)
General Form:
AX  A + X
Examples:
Remember that “H2, N2, O2, F2, Cl2, Br2, and I2” elements are diatomic when alone!!
•
Remember to balance the equation after you write the products.
2) ______________(sometimes called Combination): A reaction of _______________, typically a
metal and a nonmetal to form ________________. It is the opposite of decomposition.
General Form:
A + X  AX
Examples:
3) __________________: Reacts with oxygen gas!!! A reaction between a Carbon/Hydrogen with
_______ always produces the same… CO2 + H2O
This reaction is too easy!! Don’t miss it!
General Form: CxHy + O2  CO2 + H2O
Examples:
4) ___________ Displacement: A reaction between ________________ and _______________ that
produces a different ______________ and _____________.
General Forms: AX + Y  AY + X or AX + B  BX + A
Examples:
5) ______________ Displacement: A reaction between _________________ that are dissolved in
water that produces ________________, one of which is ___________.
Water or a gas may be one of the two compounds being produced.
General Form:
AX (aq) + BY(aq)  AY(aq) + BX (s)
A solid produced during a chemical reaction is called a ________________.
Examples:
Sections 2 and 3: Types of Reactions and Activity Series
Making Synthesis Reactions
• Metals with nonmetals  ________ compounds
Mg + O2  MgO
• Nonmetals with nonmetals  ___________ compounds
C + O2  CO2
• Metal Oxides react with water to form ______________.
CaO + H2O  Ca(OH)2
• Nonmetal Oxides react with water to form ________.
SO2 + H2O  H2SO3
Decomposition
• Decomposition of Binary Compounds
HgO  Hg + O2
• Decomposition of Metal Carbonates
CaCO3  CaO + CO2
• Decomposition of Metal Hydroxides
Ca(OH)2  CaO + H2O
• Decomposition of Metal Chlorates
KClO3  KCl + O2
• Decomposition of Acids
H2CO3  CO2 + H2O
Combustion
•
Remember, these ___________ produce CO2 and H2O.
Single Displacement
 The element that is trying to replace the other must be more reactive than the one it is replacing.
 You must use the __________________ to see if the reaction will happen.
 The Higher up it is = the more reactive it is
 Elements from Li to Na can displace hydrogen in water to form a metallic hydroxide and H2 gas.
Single Replacement Reactions
NaCl +
F2

_____ + _____
Remember the
FeCl2 +
K

_____ + _____
Activity Series!
HCl +
Zn

_____ + _____
Table 3 on page 286
HCl +
Au

_____ + _____
H2O +
Na

_____ + _____
H2O +
Fe

_____ + _____
AgNO3 +
Cu

_____ + _____
Metals Replace Metals
Al + Pb(NO3)2  Pb + Al(NO3)3
• Metals Replace Hydrogen in Water
Na + H2O  NaOH + H2
• Metals Replace Hydrogen in Acid
Mg + HCl  H2 + MgCl2
• Halogens replace halogens below them
Double Displacement
• Switch the compounds and make sure the new compounds are ______________.
• They will _______ react and switch, no activity series needed.
KI + Pb(NO3)2  PbI2 + KNO3
Once you have solved for the products of the reaction, you must then balance the reaction!