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Weekly plan 2
Arenes 2
Student book links
Specification links
Link to AS specification
Suggested time allowed (includes contact and non-contact time):
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Four to five hours
1.1.6–8
4.1.1.(e)–(h)
2.2.1 Alcohols
2.1.3 Alkenes
Suggested teaching order
Weekly learning outcomes
Students should be able to:
 Explain the relative resistance to bromination of benzene compared with alkenes.
 Describe the reactions of phenol with aqueous alkalis and with sodium to form salts.
 Discuss the role of phenol as an early antiseptic.
 Describe the reactions of phenol with bromine to form 2,4,6-tribromophenol.
 Explain the relative ease of bromination of phenol compared with benzene.
 State the uses of phenols.
Key words
Cyclohexene
Addition
Electrophile
Substitution
Acid–base
1. A comparison of the reaction of bromine with benzene and an
alkene such as cyclohexene
2. The structures of phenol and other phenols
3. The acidic properties of phenol, i.e. with sodium and sodium
hydroxide
4. The explanation of the acidic properties of phenol – in terms of
the delocalisation of oxygen’s lone pairs
5. The reaction of phenol with bromine
6. The explanation of phenol’s reactivity compared with benzene
– in terms of the delocalisation of oxygen’s lone pairs
7. The uses of phenols
How Science Works
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Phenol
Phenoxide
Delocalisation
Activation
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HSW 1 & 4 The mechanism for the addition reaction of
cyclohexene with bromine
HSW 6a The benefits of using phenol as an antiseptic
Learning styles (S = Starter activities, M = Main activities, P = Plenary activities)
ICT activities
Kinaesthetic
Activity S3
Activity M3
Activities P1&3
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Interpersonal
Activity S2
Activities M1–2
Activity P2
Auditory
Activity S2
Activities M1–2
Activity P2
Visual
Activity S3
Activities M1–3
Activities P1–2
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Research the discovery of phenol (carbolic acid) by Lister (see
Activity S1 below).
Activity M3 below could be done as a spreadsheet.
The web links referred to here are some that the author has found personally helpful but are not intended to be a comprehensive list, many other
good resources exist.
© Pearson Education Ltd 2009
This document may have been altered from the original
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Weekly plan 2
Suggested starter activities
Equipment
Teacher notes
1. Research Lister’s discovery of phenol (carbolic acid).
PCs
This should help students understand that phenol was an
extremely useful antiseptic in its time; however, harmful side
effects (e,g. blistering of skin) along with modern
developments mean that it is no longer used today.
Read about the phenols found in some herbs.
2. Students carry out a risk assessment regarding the use of
phenol in the laboratory.
Hazcards, etc.
This is in preparation for Activity M1: ‘Could phenol be used
as an antiseptic in hospitals (or the home) today?’ Students
to work in groups.
Suggested main activities
Equipment
Teacher notes
1. Give a teacher demonstration of the solubility of phenol in
water and in sodium hydroxide solution.
Phenol, sodium hydroxide solution
Risk assessment
2. Give a teacher demonstration of the reaction between
phenol and bromine.
Phenol in solution, bromine water
Risk assessment
3. Use your AS knowledge to suggest a mechanism for the
reaction of bromine with cyclohexene.
3. Draw up a table to compare the reactions of benzene and
cyclohexene with bromine.
This could be done in groups.
Suggested plenary activities
Equipment
1. Use molecular models to show the structure and reactions
of phenol.
Molecular model kits
2. Play Alcohol or phenol?
Cards with increasingly complicated
structures
Teacher notes
Students to say: ‘Alcohol’; ‘Phenol’; ‘Both’; or ‘Neither’. How
many can they correctly call in 60 seconds?
3. Write equations and name the products for the reactions
between phenol and other Group 1 metals.
© Pearson Education Ltd 2009
This document may have been altered from the original
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Weekly plan 2
4. Predict products of reactions of phenols and arenas with a
variety of electrophiles.
Whiteboard
Homework suggestions
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Write equations for the reactions of other phenols with sodium, sodium hydroxide and bromine.
Find out which antiseptics are now used in hospitals, etc. Do any have structures related to phenol?
Compare with an example the reactivity of: (i) bromine with benzene and an alkene; and (ii) bromine with benzene and phenol. Explain the differences.
Cross-curriculum links
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Biology – antiseptics
Stretch and Challenge
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Suggest an equation for the reaction between phenol and ethanoic acid. Name the product – is the reaction more or less likely to happen than with an alcohol?
Suggest or research the conditions.
Suggest five reactions that would be expected of the hypothetical molecule cyclohexa-1,3,5-triene. Give equations and name any products.
Compare the acid strength of ethanol, phenol and ethanoic acid with reference to anion stability and their reactions with Na, NaOH and Na2CO3.
Can you use the Kekulé model and the curly arrow model to explain why the bromines go into the 2,4 and 6 positions when it reacts with phenol?
Look at reactions of phenol with dilute nitric acid in comparison with benzene.
Potential misconceptions
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Students often confuse phenols with alcohols – in phenols the OH group is attached to one of the carbon atoms in the benzene ring.
Students often confuse phenols with the phenyl group.
Phenol is a compound but phenols are a class of compounds.
Notes
© Pearson Education Ltd 2009
This document may have been altered from the original
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