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Chapter 8
Chemical Reactions
Chapter 8 Notepack
NAME____________________________
Section 8.1 Describing Chemical Change
A. What is a chemical equation?
B. Why must chemical equations be balanced?
c. There are 5 general types of chemical reactions. List them below, including the general pattern for
each:
1.
2.
3. (If A = metal)
(If X = nonmetal)
4.
5. (Complete)
(Incomplete)
D. Define Reactants E. Define Products –
F. Chemists often use symbols when writing chemical equations. Look at the chart on page 206 and fill in
the following information:
1.
2.
3.
4.
5.
6.
7.
__________
__________
__________
__________
__________
__________
__________
used to separate two reactants or two products
yields, separates reactants from products
used in reversible reactions
designates a substance in the solid state, placed after the formula
designates a substance in the liquid state, placed after the formula
designates a substance in the gaseous phase, placed after the formula
designates an aqueous solution, one that is dissolved in water, placed after
the formula.
8. __________ indicates that heat is supplied to the reaction
9. __________ a formula written above or below the yield sign indicates it is used as a
catalyst. In this case, platinum.
G. What is a skeleton equation?
H. What is a catalyst?
PRACTICE PROBLEMS:
Write a skeleton equation for each of these chemical reactions
1.
Aluminum metal reacts with oxygen in the air to form aluminum oxide.
2. When solid mercury (II) sulfide is heated with oxygen, liquid mercury metal and gaseous sulfur
dioxide are produced.
3. Oxygen gas can be made by heating potassium chlorate in the presence of the catalyst
manganese dioxide. Potassium chloride is left as a solid residue.
Write sentences that completely describe each of the chemical reactions shown in these skeleton
equations.
1.
KOH(aq) + H2SO4 (aq) --> H20(l) + K2SO4(aq)
2. Na (s) + H2O (l) --> NaOH (aq) + H2 (g)
**Remember, in a chemical reaction, atoms are not created or destroyed, but simply rearranged.
**There must be the same number of each element on both sides of the equation to obey the law of
Conservation of Mass.
**Read pages 208-209, The Rules for Balancing Equations, and SUMMARIZE them below:
1.
2.
3.
4.
5.
6.
Practice Examples: Balance the following equations.
1. _____ AgNO3 + _____H2S  _____Ag2S + _____HNO3
2. _____MnO2 + _____HCl  _____MnCl2 + _____H2O + _____Cl2
3. _____Zn(OH)2 + _____H3PO4  _____Zn3(PO4)2 + _____H2O
4. ____CO + _____Fe2O3  _____ Fe + _____CO2
5. _____FeCl3 + _____NaOH  _____Fe(OH)3 + _____NaCl
Practice Examples: Rewrite these word equations as balanced chemical equations.
1. Gaseous hydrogen + solid sulfur  aqueous hydrosulfuric acid.
2. aqeous iron (III) chloride + aqueous calcium hydroxide  solid iron (III) hydroxide + aqueous
calcium chloride.
3. Solid Carbon reacts with oxygen from the air  gaseous carbon monoxide.
4. Aqueous silver nitrate reacts with solid copper to produce aqueous copper (II) nitrate and
solid silver metal.
5. Aluminum metal reacts with oxygen from the air to form solid aluminum oxide.
Section 8.2 Types of Chemical Reactions
COMBINATION REACTIONS
A. What is a combination reaction? (Sometimes called a synthesis reaction)
B. Write a general equation for a combination reaction:
C. Write the equations for the teacher demonstrations:
1.
2.
3.
**4 Good things to know about combination reactions…. (Fill in examples)
1 When a metal combines with a nonmetal, use their oxidation numbers to figure out the product.
(forms an ionic compound called a formula unit.)
Example: Potassium metal reacts with Chlorine gas
2
When two nonmetals combine, you cannot figure out the product based on oxidation numbers.
(forms a molecule and therefore we must rely on observation to predict product.)
Example: Chlorine gas reacts with bromine gas to produce trichlorine pentabromide solid.
3. When a nonmetal oxide reacts with water, it will produce an Acid.
(Start with the H and end with the O)
Example: Sulfur dioxide gas reacts with water
4. When a metal oxide reacts with water, it will produce a Base.
(start with the metal and end with hydroxide, OH-)
Example: Sodium oxide reacts with water
Practice Examples: Write the balanced equations for the following combinations…
(Use the helpful hints from above!)
1. Beryllium metal reacts with oxygen gas
2. gaseous Dinitrogen pentoxide reacts with water
3. Nitrogen gas reacts with lumps of sulfur to produce trinitrogen monosulfide.
4. Chunks of Calcium oxide is dropped into water
5. Aluminum metal rusts
Decomposition Reactions
A. Define a decomposition reaction:
B. Write a general formula for a decomposition reaction:
C. Write the equations for the teacher demonstrations:
1.
2.
3.
Helpful Hints for Decomposition Reactions
1. Some oxy-acids, when heated, decompose to form water and the nonmetal oxide.
Example: Sulfuric acid is heated
Example: Nitric acid is heated
2. Some metallic hydroxides (bases), when heated, decompose to form the metal oxide and
water.
Example: Sodium hydroxide is heated
Example: Calcium hydroxide is heated
3. Some metallic CARBONATES, when heated, decompose to form the metal oxide and carbon
dioxide gas.
Example: Copper (II) carbonate is heated
4. Some metallic CHLORATES, when heated, decompose to form the metal oxide and oxygen
gas.
Example: Potassium chlorate is heated
5. Some binary compounds, when heated or treated with electricity, will decompose into their
elements.
Example: Water decomposes when electricity is applied
Example: Silver oxide decomposes with heated
Practice Examples: Write the balanced equations for the following decompositions…
(Use the helpful hints from above!)
1. Calcium carbonate solid is heated
2. Magnesium chlorate is heated
3. Hydroiodic acid is heated
4. Magnesium hydroxide is heated
5. Sulfurous acid is heated
Single-Replacement Reactions
A. Define single-replacement reactions:
B. Write a general formula for a single-replacement reaction:
1. metal + ionic compound:
2. nonmetal + ionic compound:
Will every single replacement reaction work? Yes/No (circle one)
Define the activity series, from page 217, and explain what it is used for:
Be sure to include the nonmetals in your discussion
C. Write the equations for the teacher demonstrations here:
1.
2.
3.
Practice Problems: Write the balanced equations for the following single replacements. Be sure to
check your activity series to make sure the reaction occurs.
1. Solid magnesium metal reacts with aqueous zinc nitrate
2. Solid magnesium metal reacts with aqueous silver nitrate
3. Solid magnesium metal reacts with aqueous lithium nitrate
4. Chlorine gas reacts with aqueous magnesium iodide
5. Chlorine gas reacts with aqueous magnesium fluoride
Double – Replacement Reactions
A. Define Double-Replacement Reactions –
B. Write a general formula for a double-replacement reaction:
C. What are the three “driving forces” in this type of reaction?
1.
2.
3.
If a precipitate forms, the solubility chart is used to predict which product of the double-replacement
will be the precipitate.
** (soluble means it does dissolve in water, Insoluble means it is a precipitate - does not dissolve in
water.)
Practice: Using the solubility chart, indicate if the following are soluble or a ppt.
a. NaCl
_____________
rule # ________
name _____________________
b. BaSO4
_____________
rule # ________
name _____________________
c. Ca(NO3)2
_____________
rule # ________
name _____________________
d. AgCl
_____________
rule # ________
name _____________________
e. BaCO3
_____________
rule # ________
name _____________________
f. Li2CO3
_____________
rule # ________
name _____________________
g. KClO3
_____________
rule # ________
name _____________________
h. PbCl2
_____________
rule # ________
name _____________________
i. NaOH
_____________
rule # ________
name _____________________
Mg(OH)2
_____________
rule # ________
name _____________________
Practice Problems: Write the balanced equations for the following double-replacements. Be sure to
label the driving force.
1. Aqueous sodium hydroxide reacts with aqueous iron (III) nitrate
Driving Force _____________
2. Aqueous sodium hydroxide reacts with hydrochloric acid
Driving Force ______________
3. Aqueous sodium carbonate reacts with acetic acid to produce three products, one of
which is a gas.
Driving Force _____________
4. Solutions of barium chloride and sodium sulfate are added together
Driving Force _____________
5. Solutions of calcium hydroxide and sulfuric acid are added together
Driving Force ______________
Combustion Reactions:
A. Define a COMPLETE combustion reaction:
B. Define an INCOMPLETE combustion reaction:
C. Write the equations for the teacher demonstrations:
1.
2.
3.
Practice Problems: Write the complete balanced equation for each of the following:
1. Benzene, C6H6, completely combusts:
2. Methanol, CH3OH, incompletely combusts:
3. Glucose, C6H12O6, completely combusts:
4. Formic acid, HCOOH, incompletely combusts:
Name_______________
Hour_____________
Date____________
Chemical
Reactions
Notepack
Chapter 8