Name ____KEY_____________________________ Date ___________________ Period ___________
Chemistry
Study Guide- Chemical Reactions
Chapter 8
On the true and false questions, if it is false, correct the statement to make it
true!
1. Define a chemical reaction. Chemical reactins are changes in substances that
result in the formation of new substance(s).
2. What are the clues that a chemical reaction is taking place?1) Formation of a
gas (bubbles) 2) Color change 3) Formation of a precipitate 4) Release of
absorbance of heat
3. What is the purpose of balancing equations? (I am looking for a law here!)
Law of conservation of mass states that you cannot gain or lose mass in a
chemical reaction. There must be the same number and type of atoms on
each side of the equation.
4. When you balance equations, you must always add subscripts. T or F
You must add coefficients!
5. What are the symbols used to represent a formula as aqueous, solid, liquid,
and gas? (aq), (s), (l), (g)
6. What is a precipitate? A solid that forms from mixing 2 solutions.
7. When do precipitates form? When you mix two solutions that form a solid.
8. When going from a word equation to a formula equation, you must make
sure that each formula is balanced with proper subscripts before adding
coefficients. T or F
9. Balance the following equations:
C5H12 + 8 O2 
5CO2 +
6 H2O
Fe2(SO4)3 + 6 KOH  3 K2SO4 + 2 Fe(OH)3
2H3PO4 
H4P2O7 +
H2O
2 Na +2 H2O  2 NaOH + H2
10. How is HOFBrINCl important when balancing word equations?
You must use a subscript of 2 since they are diatomics as elements.
11. Write the formula equation and then balance for the following word
equations:
a. aluminum hydroxide is mixed with sulfuric acid to form aluminum sulfate
and water
2 Al(OH)3 + 3 H2SO4  Al2(SO4)3 + 6 H2O
b. potassium metal is added to water
2 K + 2 H2O  2 KOH + H2
c. Potassium metal is combined with elemental bromine
2 K + Br2  2 KBr
12. List all of the types of chemical reactions that we have focused on. Then,
describe how you can tell what type of reaction it is by only looking at the
reactants!
a. Synthesis (element + element) (Metal oxide + water ) (Metal oxide + CO2)
b. Combustion- CHO + O2  CO2 + H2O
c. Decomposition- Compound  element + element (or reverse of synthesis)
H2O2  H2O + O2
Metal chlorate  metal chloride + O2
d. Single replacement- metal + compound 
halogen + compound 
ACTIVITY series!
e. Double replacement- compound + compound  compound compound
AB + CD  AD + CB
13. What products form when metal carbonates decompose? Metal oxide + CO2
14. What products form when metal chlorates decompose? Metal chloride + O2
15. What products forms when metal oxides react with water? Metal hydroxides
16. What products forms when hydrogen peroxide decomposes? H2O + O2
17. What products forms when nonmetallic oxides combine with water? acids
18. What are the products of combustion of hydrocarbons or alcohols? CO2 + H2O
19. What is an activity series? What does it tell you? Activity series tells you the
reactivity ranking of metals. More active metals can replace less active ones
in a compound.
20. For the following, tell what type of reaction is present and then predict the
products:
a.
aluminum metal is added to copper (II) chloride solution
SR products: AlCl3 + Cu
b.
ammonia gas is mixed with excess oxygen
Combustion- NO2 + H2O
c.
chlorine gas is passed over sodium iodide solid
SR- I2 + NaCl
d.
hydrochloric acid is mixed with potassium hydroxide
DR- H2O + KCl
e.
iron metal is heated strongly in air
Combustion or synthesis - FeO
21. Elemental sulfur comes with a subscript of 8 and elemental phosphorus
comes with a subscript of 4. T or F