CHAPTER 2
ANSWER KEY
BLM 2-1, Writing Names and Formulas of
Binary Ionic Compounds/Science Inquiry
BLM 2-2, Ionic or Molecular?/Science
Inquiry
Goal: Students demonstrate their ability to write the names
and formulas of chemical compounds and their ability to
distinguish between ionic and molecular compounds.
Goal: Students demonstrate their understanding of the
differences between ionic and molecular compounds.
Answers
Answers to the questions for Investigation 2-A: Writing
Names and Formulas of Binary Ionic Compounds are
provided in the SCIENCEFOCUS 10 Teacher’s Resource.
Answers
Observations for Investigation 2-B: Ionic or Molecular?
are provided in the SCIENCEFOCUS 10 Teacher’s
Resource.
BLM 2-3, Chemical Names and Formulas/Reinforcement
Goal: Students practise naming and writing formulas for different substances.
Answers
Answers are in boldface.
Chemical
formula
NH4Cl
K2S
CI4
CaO
NH4Cl
Li3N
Mg(OH)2
ZnO
CuNO3
SiO2
OCl2
CuCl
FeCl2
CaS
Ca(HCO3)2
P2O5
SiBr4
Al(BrO3)3
Ca(HS)2
NH4NO2
Ionic or
molecular?
ionic
ionic
molecular
ionic
ionic
ionic
ionic
ionic
ionic
molecular
molecular
ionic
ionic
ionic
ionic
molecular
molecular
ionic
ionic
ionic
Name of compound
ammonium chloride
potassium sulfide
carbon tetraiodide
calcium oxide
ammonium chloride
lithium nitride
magnesium hydroxide
zinc oxide
copper(I) nitride
silicon dioxide
oxygen dichloride
copper(I) chloride
iron(II) chloride
calcium sulfide
calcium hydrogen carbonate
diphosphorus pentaoxide
silicon tetrabromide
aluminum bromate
calcium hydrogen sulfide
ammonium nitrite
Chemical
formula
AgCH3COO
CaCrO4
N2O5
Fe2(CO3)3
HgS
AgHSO4
KMnO4
Mg(OH)2
AlPO4
CS2
K2SO4
SnF2
K2Cr2O7
HgS
Na2B4O7
V2O5
(NH4)2Cr2O7
Bi3(PO4)5
Na2SiO3
Co3(PO4)2
Ionic or
molecular?
ionic
ionic
molecular
ionic
ionic
ionic
ionic
ionic
ionic
molecular
ionic
molecular
ionic
ionic
ionic
ionic
ionic
ionic
ionic
ionic
Name of compound
silver acetate
calcium chromate
dinitrogen pentaoxide
iron (III) carbonate
mercury(II) sulfide
silver hydrogen sulfate
potassium permanganate
magnesium hydroxide
aluminum phosphate
carbon disulfide
potassium sulfate
tin(II) fluoride
potassium dichromate
mercury(II) sulfide
sodium tetraborate
vanadium(V) oxide
ammonium dichromate
bismuth(V) phosphate
sodium silicate
cobalt(II) phosphate
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CHAPTER 2
ANSWER KEY
BLM 2-4, Chemical Formulas Quiz/
Assessment
BLM 2-6, Acid or Base Pre-Test/
Assessment
Goal: Students demonstrate their knowledge of chemical
formulas.
Goal: Students demonstrate their understanding of the
concepts, procedures, and safety precautions used in Find
Out Activity: Acid or Base?
Answers
Answers
Answers are in boldface.
1.
Name
sodium chloride
dinitrogen trioxide
magnesium oxide
lithium iodide
tetraphosphorus decaoxide
carbon dioxide
strontium hydroxide
potassium sulfide
carbon trisulfide
copper(II) bromide
iron(III) iodide
barium phosphate
aluminum hydroxide
ammonium cyanide
tetranitride pentachloride
gallium hydrogencarbonate
iron(III) nitrate
gold(III) sulfate
iron(II) carbonate
niobium(V) hydroxide
2. (a)
(b)
(c)
(d)
Ionic or
Formula
molecular?
NaCl(s)
ionic
N2O3
molecular
MgO(s)
ionic
LiI
ionic
P4O10(s)
molecular
CO2
molecular
Sr(OH)2
ionic
K2S
ionic
CS3
molecular
CuBr2
ionic
FeI3
ionic
Ba3(PO4)2 ionic
Al(OH)3
ionic
NH4CN
ionic
N4Cl5
molecular
Ga(HCO3)3 ionic
Fe(NO3)3
ionic
Au2(SO4)3 ionic
FeCO3
ionic
Nb(OH)5
ionic
H 2O
CH4
NH3
CH3OH
BLM 2-5, The Crossover Method/Skill
Builder
Goal: Students learn an alternative method for writing
formulas and determining cation charges.
Answers
1. (a)
(b)
(c)
(d)
CaBr2
Li2O
FeCl3
CoS
2. (a)
(b)
(c)
(d)
Cu+
Ni2+
Pd2+
Ti4+
1. The safety glasses, gloves, and lab apron serve the
same purpose: to protect against accidental spills and
contact with corrosive acids and bases. The eyewash
station and safety showers are both used to
immediately dilute any acid or base that has contacted
living tissues, to the point at which it is not
concentrated enough to cause significant damage.
2. (a) Using a base to neutralize an acid spill to tissue is
not a good idea because it is difficult to judge the
correct amount to use. Too little base, and the
acid will still be corrosive. Too much base, and
the corrosive base will damage the tissue. Also,
the heat generated by the reaction can further
damage skin.
(b) The student should immediately dilute the acid on
the affected area by flushing with lots of cold
water for several minutes.
3. A pH meter relies on the change in electrical
conductivity produced by the formation of hydrogen
cations or hydroxide anions. An acid-base indicator
relies on the colour change that occurs when the
indicator reacts with hydrogen or hydroxide ions. A
pH meter gives very accurate results (to a precision of
several decimal places) when properly calibrated. An
acid-base indicator usually tells you only whether a
substance is acidic or basic.
BLM 2-7, Acid and Base Quiz/
Assessment
Goal: Students demonstrate their ability to identify acids
and bases by their properties and demonstrate their
understanding of terms related to acids and bases.
Answers
1. (a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
Arrhenius, H+
less than
lower
blue, red, turns pink
conduct
Arrhenius, OH–
sour
greater than
higher
red, blue, remains colourless
conduct
bitter
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
CHAPTER 2
ANSWER KEY
2. Answers are in boldface.
Chemical
Name of
formula of
Name of
substance
aqueous solution
acid or base
hydrogen sulfide
H2S (aq)
hydrosulfuric acid
H2CO3 (aq)
hydrogen
carbonic acid
carbonate
phosphoric acid
hydrogen
H3PO4 (aq)
phosphate
magnesium
Mg(OH)2 (aq)
magnesium
hydroxide
hydroxide
solution
NH4OH (aq)
ammonium
ammonium
hydroxide
hydroxide
solution
hydrogen chlorate
HClO3 (aq)
chloric acid
hydrogen acetate CH3COOH (aq)
acetic acid or
ethanoic acid
sulfurous acid
hydrogen sulfite
H2SO3 (aq)
3. Baking soda can act as either an acid or a base. This
property means that it can neutralize both acids and
bases.
BLM 2-8, Home-Grown Indicators/
Science Inquiry
Goal: Students demonstrate their understanding of the
differences between acidic and basic substances.
Answers
Answers to the questions for Find Out Activity: HomeGrown Indicators are provided in the SCIENCEFOCUS 10
Teacher’s Resource.
BLM 2-9, Physical Properties of Water/
Science Inquiry
Goal: Students demonstrate their understanding of the
properties of water.Answers
Answers
Answers for Investigation 2-D: Physical Properties of
Water are provided in the SCIENCEFOCUS 10 Teacher’s
Resource.
BLM 2-10, Chapter 2 Test/Assessment
Goal: Students demonstrate their understanding of the
information presented in Chapter 2.
Answers
1. F: Blue litmus paper turns red in the presence of an
acid.
2. F: Basic solutions and neutral solutions are also
capable of conducting electricity.
3. T
4. F: The names of binary ionic compounds almost
always end in “ide.”
5. F: Only cations that have more than one possible
charge should be named using the Stock system.
6. (f)
7. (k)
8. (g)
9. (l)
10. (e)
11. polar
12. molecular
13. Stock
14. ionic
15. hydrogen
16. (a)
17. (d)
18. (d)
19. (b)
20. (c)
21. (a)
22. (a)
23. (d)
24. (c)
25. (c)
26. An ionic bond exists between a cation and an anion in
an ionic compound. An ionic bond is formed when
electrons are transferred from a metal to a non-metal.
A covalent bond exists within a molecular compound.
A covalent bond is formed when non-metals share
electrons.
27. You do not use the Stock system to name sodium
cations. Sodium forms only one cation: Na+.
Therefore, there is no need to indicate its charge.
28. Acids dissolve in water to release H+ ions. Bases
dissolve in water to release OH– ions.
29. (a) Substance A is a base because it turns red litmus
blue and conducts electricity.
Substance B is an ionic compound because it
conducts electricity when dissolved in water.
Substance C is a molecular compound because it
is a liquid at room temperature and does not
conduct electricity or change the colour of litmus.
Substance D is an acid because it turns blue
litmus red when dissolved in water and also
conducts electricity when dissolved in water.
(b) Answers are in boldface.
Correct
chemical
Substance letter
Substance
formula
(A, B, C, or D)
methanol
CH3OH(l)
C
hydrogen sulfide
H2S(g)
D
sodium hydroxide
NaOH(aq)
A
(aqueous solution)
ammonium sulfide (NH4)2S(aq)
B
(aqueous solution)
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.