Name ____________________________________
Period ____________
8-1 Describing Chemical Reactions
1. What are chemical reactions?
a. Chemical reaction –
The formation of new substances involves the breaking chemical bonds of the reactants
and forming chemical bonds of the products
ii. When bonds are broken and formed energy is released and absorbed
iii. ways energy is released in a chemical reaction:
1.
i.
2.
3.
4.
iv. When new chemical bonds form the reaction makes a new substance (product) that can
also be observed:
1.
2.
3.
4.
2. What are the mechanics of a chemical reaction?
𝑯𝟐(𝒈) + 𝑶𝟐(𝒈) → 𝑯𝟐 𝑶(𝒍)
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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How would you read this reaction:
8-2 Balancing Equations
1. How are equations used in chemistry?
a. Conservation of mass
-
b. All chemical equations must obey the law of Conservation of mass
In a chemical reaction:
The number of atoms in the reactants (mass of the reactants)
- must equal The number of atoms in the products (mass of the products)
c. How do you make sure equations obey the law of conservation of mass?
d. What is the difference between Subscripts and coefficients?
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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e. What do you change when balancing a equation?
H2(g) + O2(g)  H2O
Is NOT balanced if you where to change the subscripts:
H2(g) + O2(g)  H2O2
this equation now reads that hydrogen gas and oxygen gas react to form peroxide that you use to clean out a cut,
not water that you drink
Is balanced if you where to change the number of molecules that go into and out of the reaction:
2H2(g) + O2(g)  2H2O
This equation reads that two hydrogen molecules and 1 oxygen
molecule react to form 2 water molecules
4
Start
H atoms
End
4H
atoms
2O
atoms
2 O atoms
Balance the following equations:
H2
P
NaNO3
C8H18
Misuro Chemistry 5.0
Unit 8 – Chemical equations
Page 3 of 9
+
+
+
N2
→
O2
→
O2
→
NaNO2
→
CO2
NH3
P2O5
+
O2
+
H2O
8-3 Classifying Chemical Reactions
1. How are chemical reactions classified?
a. There are 5 types of chemical equations:
1.
2.
3.
4.
5.
2. What are Combustion Reactions?
i. Reactants:
ii. Products:
iii. Combustion reactions usually involve expositions and flames
iv. How to balance combustion reactions:
1.
2.
3.
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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Balance these combustion reactions:
C2H6
+ O2
C4H6
→ CO2 + H2O
+ O2
→
C6H12O6 + O2 →
3. What are Synthesis Reactions?
a. Reactants:
b. Products:
i. Synthesis -
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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Balance these synthesis reactions:
H2 + N2  NH3
Na + Cl2 
Iron (III) + Oxygen gas 
4. What are Decomposition Reactions?
a. Reactants
b. Products:
c. Decompose -
break apart
d. How are synthesis reactions related to decomposition reactions?
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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5. What are single replacement reactions?
a. Reactants:
b. Products:
c. A Singe replacement reactions will only take place when a more reactive
element replaces a less reactive element
i. An activity series can be used to predict whether a single
replacement reaction will occur or not.
More Reactive
Less Reactive
ii. The general form of a single replacement reaction is:
A
Fe
3Mg
Ag
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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+
+
+
+
BX
CuSO4
2Al(NO3)3
Pb(NO3)2
→
AX
+ B
→
FeSO4
+ Cu
→ 3Mg(NO3)2 + 2Al
→
No RXN
Balance these singe replacement reactions:
Na +
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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Na2O + H2
Li
+
NaCl 
Cu
+
ZnSO4 
6. What are Double-Replacement Reactions?
a. Reactants:
b. Products:

H2O
Balance these Double replacement reactions:
CoCl2 +
Na2O
FeO
+
CuO +

CoO + NaCl
Al(NO3)3 
ZnSO4 
Classify and balance the following equations:
Misuro Chemistry 5.0
Unit 8 – Chemical equations
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