CHAPTER
REVIEW
6
The following icons indicate the Achievement Chart
category addressed by each question.
What Do you Remember?
1. Zinc oxide, ZnO, is an active ingredient in some
sunscreens. Zinc oxide can be made by heating
zinc sulfide strongly in air:
2 ZnS(s) + 3 O2(g) → 2 ZnO(s) + 2 SO2(g)
the coefficient for zinc sulfide
the number of sulfur atoms in sulfur dioxide
the coefficient for oxygen (the element)
the number of different reactants
the total number of reactant molecules
the states of matter present in this reaction
(6.1)
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2. The combustion of hydrocarbons sometimes
producesayellowflameandasootyresidue.(6.9)
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(a) Describe the conditions when this might occur.
(b) Name this type of combustion.
What Do you Understand?
3. Consider the six types of reactions discussed
in this chapter. All involve elements and
compounds. Identify the type(s) of reaction that
has the following reactants:
(a) two elements
(b) two compounds
(c) oxygen and
afuel
(d) only one
compound
(e) an element and a
compound(6.5–6.10)
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5. Hydrogenperoxideisaclear,colourlessliquid
used to disinfect cuts. The chemical equation for
the decomposition of hydrogen peroxide is
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T/I
(a) Explain the difference between the state
symbols (aq) and (l).
(b) Predict what you would expect to see in a
test tube of hydrogen peroxide undergoing
this reaction.
(c) Describe how to tell when the reaction is
complete.
(d) Predict how the mass might change as the
reaction proceeds. Explain.
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Chapter 6 • Chemicals and Their Reactions
Knowledge/Understanding
Communication
Thinking/Investigation
Application
T/I
A
6. People can choose to have the underside of their
vehicle sprayed with oil once a year. How does a
coating of oil help prevent rusting? (6.10)
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A
7. Balance and classify each of the following
chemical equations. (Note that some may fit into
more than one category.) (6.3–6.9)
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
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K2O → K + O2
Na + I2 → NaI
Cu(NO3)2 + NaOH → Cu(OH)2 + NaNO3
KClO3 → KCl + O2
Ca(NO3)2 + HBr → CaBr2 + HNO3
Sn(OH)2 → SnO + H2O
P4 + N2O → P4O6 + N2
Fe + Al2(SO4)3 → FeSO4 + Al
AlCl3 + Na2CO3 → Al2(CO3)3 + NaCl
C3H6 + O2 → CO2 + H2O
8. Explain why you should not cook on a barbecue
in an enclosed space. (6.9)
T/I
A
9. The following chemical reactions take place, one
afteranother,whenanautomobileairbaginflates.
Balance and classify each reaction. (6.3–6.6)
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(a) Th
egasneededtoinflatethebagcomesfrom
the reaction of sodium azide, NaN3.
NaN3(s) → N2(g) + Na(s)
4. Use the law of conservation of mass to explain
why chemical equations should be balanced.
(6.2, 6.3)
2 H2O2(aq) → 2 H2O(l) + O2(g) (6.1, 6.3)
C
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Referring to this chemical equation, write
(a)
(b)
(c)
(d)
(e)
(f)
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(b) The sodium produced in reaction (a) is
dangerous. It is removed by a reaction with
iron(III) oxide, Fe2O3, in the airbag.
Na(s) + Fe2O3(s) → Na2O(s) + Fe(s)
(c) The sodium oxide quickly reacts with carbon
dioxide and moisture from the air to form
sodium hydrogen carbonate.
Na2O(s) + CO2(g) + H2O(g) → NaHCO3(s)
solve a Problem
10. Fuels burn faster as the concentration of oxygen
is increased. For example, iron wool burns in
pure oxygen to produce iron(III) oxide and a
great deal of energy. (6.1, 6.3, 6.9)
K/U
T/I
(a) Write the word and chemical equations for
this reaction.
(b) Design an experiment using this reaction to
confirm the law of conservation of mass.
NEL
11. A student placed a piece of zinc metal in a
solution of hydrochloric acid. The chemical
equation for the reaction that occurred is
14. (a) Develop a visual organizer, such as a chart or
a consequence map, to show the risks and
benefits of burning fossil fuels.
Zn(s) + 2 HCl(aq) → H2(g) + ZnCl2(aq)
(b) Write two paragraphs, each written from
a different perspective, outlining why we
should (or should not) continue to burn
fossil fuels for energy. (6.9)
The following data were collected from the
experiment:
initialmassofzincreacted:
2.5g
initialmassofhydrochloricacid: 52.6g
finalmassofsolution: 54.8g
(6.3,6.5)
A
Reflect on your learning
T/I
(a) Calculate the mass of hydrogen produced.
(b) Do the results of this experiment violate the
law of conservation of mass? Explain.
12. Two properties that make gasoline potentially
dangerous are that it evaporates quickly at room
temperature and that its vapour ignites readily.
Despite these hazards, many homeowners keep
a small amount of gasoline on hand to fuel small
devices like lawn mowers and snowblowers.
What must be considered when handling or
storing gasoline? Explain your answer. (6.9)
A
Create and Evaluate
13. A routine test of the drinking water at Edgevale
High School revealed slightly higher than normal
concentrations of lead. Exposure to lead is
known to slow brain development, particularly in
children. The lead was coming from the corrosion
of the solder metal used to join lengths of copper
pipe together. Edgevale school officials were faced
with a difficult decision. Closing the school was
not an option. The copper pipes could not be
replaced until the following summer. However,
staff and students needed a safe supply of drinking
water now. Two options being considered were
• providingbottledwaterforall1500staff
and students or
• turningonalldrinkingfountainsforat
least 20 minutes each morning before
studentsarrive.(After20minutes,thelead
concentrations decreased to within the
“normal” range.) (6.10)
(a) List the risks and benefits of both options.
(b) If you were the school principal, which
option would you choose? Why?
A
15. (a)Howrelevantwastheideaofachemical
reaction to you before reading this chapter?
(b) Outline how your understanding of the role of
chemical reactions in your life has changed.
Web Connections
16. What is the “fire triangle”? How does it relate to
the work of firefighters? (6.10)
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A
17. The “carbonyl process” is a method of refining
nickel that involves passing carbon monoxide
gas over impure nickel at high temperature. This
produces a compound called nickel carbonyl:
Ni(s) + CO(g) → Ni(CO)4(g)
Nickel carbonyl is then strongly heated to
produce pure nickel and carbon monoxide gas:
Ni(CO)4(g) →Ni(s)+CO(g)(6.5)
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T/A
(a) Classify each of these reactions.
(b) Research the properties of nickel carbonyl and
carbon monoxide. Why must the reactions be
conducted in an airtight chamber?
18. Dinitrogen monoxide is also known as nitrous
oxide, N2O(g). Dentists sometimes use this gas to
relax their patients. Nitrous oxide can be made
from solid ammonium nitrate. Water is also
producedinthisreaction.(6.3,6.5,6.9)
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C
A
(a) Write the chemical equation for this reaction.
(b) Classify this reaction.
(c) Research how nitrous oxide can be used to
improve the performance of racing cars.
Summarize your findings in a short web
article for car enthusiasts. Include safety advice
regarding the use of nitrous oxide in car engines.
To do an online self-quiz or for all
other Nelson Web Connections,
Go to NElsoN sCIENCE
NEL
Chapter 6 Review
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