BLM 2-1, Writing Names and Formulas of Binary Ionic Compounds/Science Inquiry

CHAPTER 2

ANSWER KEY

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BLM 2-1, Writing Names and Formulas of Binary Ionic Compounds/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.

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.

BLM 2-2, Ionic or Molecular?/Science Inquiry

Goal: Students demonstrate their understanding of the differences between ionic and molecular compounds.

Answers

Observations for Investigation 2-B: Ionic or Molecular? are provided in the SCIENCEFOCUS 10 Teacher’s Resource.

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BLM 2-3, Chemical Names and Formulas/Reinforcement

Goal: Students practise naming and writing formulas for different substances.

Answers

Answers are in boldface.

ZnO

CaS

CHAPTER 2

ANSWER KEY

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.

BLM 2-4, Chemical Formulas Quiz/ Assessment

Goal: Students demonstrate their knowledge of chemical formulas.

Answers

Answers are in boldface.

1.

LiI

2. (a) H2O

(b) CH4

(c) NH3

(d) 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) CaBr2

(b) Li2O

(c) FeCl3

(d) CoS

2. (a) Cu+

(b) Ni2+

(c) Pd2+

(d) Ti4+

BLM 2-6, Acid or Base Pre-Test/ Assessment

Goal: Students demonstrate their understanding of the concepts, procedures, and safety precautions used in Find Out Activity: Acid or Base?

Answers

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) Arrhenius, H+

(b) less than

(c) lower

(d) blue, red, turns pink

(e) conduct

(f) Arrhenius, OH–

(g) sour

(h) greater than

(i) higher

(j) red, blue, remains colourless

(k) conduct

(l) 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

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.

2. Answers are in boldface.

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: Home-Grown 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.

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.