Video Education
Australasia
Bringing Learning to Life
Program Support Notes
Middle - Senior Secondary
30mins
Acids and Bases
Teacher Notes by Keir
Strahan, B.Sc. Dip.Ed.
Produced by Video Education Australasia
Commissioning Editor Christine Henderson B.Sc.
Ph.D. Dip.Ed.
Mark McAuliffe Dip.Art (Film &
TV) Dip.Ed. B.Ed. Ph.D.
Executive Producer
© Video Education Australasia Pty. Ltd.
Suitable for:
Chemistry
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Acids and Bases
For Teachers:
Brief Summary of Program
Acids and bases are all around us. The program features the following: early theories of Arrenhius and
Lowry-Bronsted. Valence structures, exposed protons and proton transfer. Diprotic and triprotic acids
linked to structures. Amphiprotic example given by hydrogen sulphate ion. The pH scale and the use of
indicators to measure pH. Conjugate pairs and strengths of acids with strong acids giving weak
conjugate bases. Standard reactions: acid + metal, acid + oxide, acid + carbonate, acid + hydrogen
carbonate.
Introduction
Acids and bases are an important part of life. From their presence in food, to their use as cleaning
agents and electrolytes, this program introduces them in familiar settings. The corrosive properties of
acids and bases are demonstrated by the impact that acid rain has on the environment and building
structures, and by the caustic properties of alkaline oven cleaners.
The chemistry of acids and bases is then examined. The theories of Svante Arrenhius and LowryBronsted lead into an analysis of the structures of a number of common acids. The need for an exposed
proton is clearly explained and the mechanism of an acid-base reaction is graphically demonstrated as
we see a proton transfer between water and hydrochloric acid. Examples of diprotic and triprotic acids
are provided and the amphiprotic nature of the hydrogen sulphate ion is addressed with clear graphics.
The pH scale and its relationship to the concentration of dissolved hydronium ions is linked with the
use of indicators in analytical chemistry. Indicators are described as weak acids and a number of
common indicators are used to show changes in pH.
Acid-base conjugate pairs are then considered and the extent that an acid ionises is used to explain the
differences observed in the strengths of certain acids. The program concludes with a look at some
common acid-base reactions as acids are mixed with metals, oxides, carbonates and hydrogen
carbonates. Chemical equations accompany all of the reactions that are demonstrated.
Program Timeline
00.30
01.38
06.10
06.48
12.01
12.56
15.57
16.41
19.00
19.43
23.33
24.25
27.27
29.22
29.55
30.20
Introduction
Properties and uses
Summary
What are acids and bases
Summary
The pH scale
Summary
Indicators
Summary
Acids and bases conjugate pairs and strengths
Summary
Common reactions of acids
Summary
Conclusion
Credits
Acids and bases end
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Acids and Bases
For Students:
While Viewing the Program
1. Acids and bases are 2 chemical groups. What other types of chemical groups can you name?
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2. What does corrosive mean?
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3. What common 2 pollutants produced from the burning of fossil fuels lead to acid rain?
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4. What effect does acid rain have on trees, buildings and statues?
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5. What does the word “neutralise” mean to you?
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6. What does it mean when we say that acids and bases neutralise each other?
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7. Heartburn is a burning sensation in your chest that is caused by hydrochloric acid from the stomach
affecting the oesophagus. Which property of acids and bases is responsible for this burning?
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8. Why is vinegar useful as a cleaning product?
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9. Explain why indicators are useful in analytical chemistry that involves acids and bases.
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Acids and Bases
10. What is an electrolyte? Why do acids make good electrolytes when they are dissolved in water?
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11. How did Svante Arrenhius explain the fact that acids and bases neutralise each other?
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12. What do all acids have in common?
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13. How many electrons and protons do hydrogen atoms have?
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14. What is the Lowry-Bronsted theory of acids and bases?
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15. When sulphuric acid is dissolved in water it ionises. Is this an acid-base reaction? Explain your
answer.
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16. Annotate the equation for the reaction between hydronium ions and hydroxide ions in order to
show that it is an acid-base reaction.
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17. Ethanoic acid has the molecular formula CH3COOH. It contains 4 hydrogen atoms and yet it is
monoprotic. Explain why ethanoic acid is monoprotic.
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18. What is an amphiprotic substance? Write out the formulas of some amphiprotic substances.
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Acids and Bases
19. What is pH?
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20. What is the pH of solutions with H3O+ concentrations of 10-2, 10-6.5 and 10-11.1? Which of these pH
values are acidic and which are basic? Demonstrate that 10-3 is a larger number than 10-8 and hence
show that acidic solutions have a higher concentration of ions than basic solutions.
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21. How can you measure the pH of substances?
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22. Name 4 common substances and their pH values. Which are acidic and which are basic?
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23. What are indicators?
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24. How does Universal Indicator differ from other indicators? Why can it be used to measure pH
whereas an indicator such as Phenolphthalein cannot?
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25. What is a conjugate base? Why is the chloride ion (Cl-) the conjugate base of hydrochloric acid
(HCl)?
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26. What is the difference in molecular formula between a conjugate acid and its base? Use an
example in your answer.
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Acids and Bases
27. Explain how measuring the conductivity of an acid in solution can identify it as being a strong or
weak acid.
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28. Is the chloride ion (Cl-) a strong or weak conjugate base?
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29. Vinegar contains ethanoic acid (CH3COOH) which is a weak acid. Is its conjugate base relatively
weak or strong?
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30. Compose a generalisation for the strengths of conjugates acids and bases compared to the strengths
of the acids and bases from which they are derived.
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31. Why is the reaction between magnesium (Mg) and hydrochloric acid (HCl) not classed as an acid
base reaction?
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32. Write a general equation for the reaction between an acid and an oxide.
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33. Write a general equation for the reaction between an acid and a carbonate.
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34. Write a general equation for the reaction between an acid and a hydrogen carbonate.
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6
Acids and Bases
Web Site References
• Clearly covers the theory of acids and bases
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch11/acidbaseframe.html
• Directory with many links to acid-base sites
http://search.looksmart.com/p/browse/us1/us317914/us263953/us263958/us330416/us330423/
• Introduction to acids and bases with examples of common acid-base reactions
http://www.rjclarkson.demon.co.uk/junior/junior.htm
• Introductory unit into acids and bases
http://www.visionlearning.com/library/module_viewer.php?mid=58
• Directory with many sites that relate to acids and bases and how they impact on the environment
http://www.westfieldnj.com/eis/team6/6science_ch6.htm#Neutralization
• A fun game of memory that asks players to match definitions to other terms
http://www.glencoe.com/sec/science/Science600/co/617.php?iRef=617
Other Relevant Programs Available from VEA
Chemical Equations
Our Chemical Environment Series
The Super-Charged World of Chemistry Series
Applied Chemistry – Science Bank Series
The Amazing Mole
Please visit our website for many more relevant programs www.vea.com.au
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