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UNIT06.indd

Statement

Topic

1a

Using scientific ideas and models to explain phenomena and developing them to generate and test theories.

7Ec, 7Ed, 7Ee

1b

Critically analysing and evaluating evidence from observations and experiments.

all

2a

Exploring how the creative application of scientific ideas can bring about technological developments and consequent changes in

the way people think and behave.

7Ed, 7Ee

2b

Examining the ethical and moral implications of using and applying science.

7Ee

3a

Recognising that modern science has its

roots in many different societies and cultures

and draws on a variety of valid approaches

to scientific practice.

7Ea, 7Ec, 7Ed

4a

Sharing developments and common understanding across disciplines and boundaries.

7Ee

Links with other units

7H

Rocks and weathering.

9E

Reactions of metals and metal compounds.

8H

The rock cycle.

Cross-curricular links

Topic

Links

7Eb

Food technology

7Ec,

7Ed

Art

7Ee

Geography

Statement

Topic

2c

Elements and compounds show characteristic chemical properties and patterns in their behaviour.

all

4c

Human activity and natural processes can lead to changes in the environment.

7Eb, 7Ee

Code

Framework threads

Year 7

Topic

1.2a

Using investigative approaches: planning an approach

Describe an appropriate approach to answer a scientific question using a limited range of information and making relevant observations or measurements.

7Ed, 7Ee

1.2b

Using investigative approaches: selecting and managing variables

Recognise the range of variables involved in an investigation and decide which to control.

7Ed, 7Ee

1.2c

Using investigative approaches: assessing risk and working safely

Explain how action has been taken to control obvious risk and how methods are adequate for the task.

7Ea, 7Eb, 7Ec

7Ed, 7Ee

1.2d

Using investigative approaches: obtaining and presenting primary evidence

Describe and record observations and evidence systematically.

7Eb, 7Ec, 7Ed

7Ee

Recognise that the presentation of experimental results through the routine use of tables, bar charts and simple graphs makes it easier to see patterns and trends.

7Eb, 7Ed, 7Ee

1.2e

Working critically with primary evidence

Describe patterns and trends in results and link this evidence to any prediction made.

7Ec, 7Ed, 7Ee

Describe and suggest how planning and implementation could be improved

7Ed, 7Ee

1.2f

Working critically with secondary evidence

Describe patterns and trends in secondary evidence and link these to the prediction or conclusion drawn.

7Ea, 7Eb, 7Ee

Recognise that different conclusions may be drawn from secondary data.

7Eb, 7Ec

Code

Framework sub-strands

Year 7

Topic

3.2

Chemical reactions

Sort some reactions into reversible and irreversible.

7Ee

Recognise that new materials are made during chemical reactions.

7Ee

3.3

Patterns in chemical reactions

Describe, record and group observations from chemical reactions.

7Ea, 7Ec, 7Ed

7Ee

Topic

Level

Learning objectives covered

Key words

Tasks

7Ea

Must

All pupils must: realise that acids can be hazardous; work safely with dilute acids; be able to deal with acids and alkalis if they are splashed on the skin; describe some hazard warnings used on laboratory chemicals and road tankers.

acid, alkali

Starter 1, Starter 3, Starter 5, Explaining 1, Exploring 3, Plenary 2, Homework 1

Should

Most pupils should: describe what is mean by a risk assessment; identify the hazard warning symbols

for corrosive and irritant substances; describe how dilution with water can reduce the hazard of an

acid or alkali; give the names of the three common laboratory acids: sulphuric acid, nitric acid and

hydrochloric acid; give some examples of the uses of acids; use the Hazchem code to identify the

hazards of chemicals.

corrosive, hydrochloric acid, irritant, nitric acid, risk assessment, sulphuric acid

Starter 1, Starter 2, Explaining 1, Starter 5, Exploring 3, Plenary 1, Homework 1

Could

Some pupils could: describe in detail how the Hazchem code is used by the emergency services.

Starter 1, Starter 2, Explaining 1, Starter 5, Exploring 3, Plenary 1, Homework 2

7Eb

Must

All pupils must: state that acids have a sour or sharp taste.

acid

Starter 2, Exploring 4, Exploring 2, Explaining 1, Explaining 2, Plenary 1, Homework 1

Should

Most pupils should: state that vinegar and citrus fruits are acidic; identify some everyday uses of acids,

for example in preserving foods; describe how some acids used in the home are less hazardous than

those used in laboratories.

Starter 1, Starter 2, Exploring 4, Exploring 2, Explaining 1, Explaining 2, Plenary 2, Plenary 3, Homework 1

Could

Some pupils could: carry out detailed research into the positive and negative effects of acids in the home and in the environment.

Starter 2, Exploring 5, Exploring 3, Explaining 1, Explaining 3, Exploring 1, Plenary 3, Exploring 5 (as homework)

7Ec

Must

All pupils must: describe the colour change of litmus indicator with different substances; explain that alkalis have the opposite effect on indicators from acids; describe substances which are neither acidic nor alkaline as neutral; develop skills in the use of a pestle and mortar, and filtration techniques.

acid, alkali, indicator, litmus, neutral

Starter 1, Explaining 1, Exploring 1, Explaining 2, Plenary 1, Homework 1

Should

Most pupils should: state that most indicators are derived from plant colours; critically evaluate the results of experiments with indicators; explain that the neutral (purple) form of litmus is a mixture of the red and blue forms; state that alkalis are at least as corrosive as acids.

Starter 1, Starter 2, Explaining 1, Exploring 1, Explaining 2, Plenary 3, Homework 1

Could

Some pupils could: explain the role of Arabic scientists in developing the concept of an alkali.

Starter 1, Explaining 1, Exploring 1, Explaining 2, Plenary 3, Plenary 4, Homework 1

7Ed

Must

All pupils must: use universal indicator to test solutions for acidity and alkalinity and to measure pH;

give examples of everyday substances that are acids or alkalis.

pH

Starter 1, Starter 2, Exploring 2, Explaining 2, Plenary 1, Homework 1

Should

Most pupils should: explain that in the past there were a number of competing theories to explain acidity; describe the main features of the pH scale and classify solutions as strong or weak acids or alkalis; identify the pH of a solution using universal indicator.

strong/weak (as applied to acids), universal indicator

Starter 1, Starter 2, Exploring 1, Exploring 2, Explaining 2, Plenary 2, Homework 2

Could

Some pupils could: explain that all acids contain hydrogen; use ideas about colour mixing to explain how universal indicators are made, and how they work; describe some alternative theories to explain acidity and explain some evidence for the currently accepted theory.

Starter 2, Exploring 1, Exploring 3, Exploring 4, Explaining 2, Plenary 2, Homework 3

7Ee

Must

All pupils must: explain that a neutral solution can be obtained by adding an acid to an alkali;

recognise that the building of a chemical factory may cause controversy.

Starter 2, Exploring 1, Explaining 1, Plenary 2, Homework 2

Should

Most pupils should: describe pH changes on neutralisation or dilution of an acid or an alkali; link the strength of acids and alkalis to the potential hazards; describe some applications of neutralisation reactions; be able to state some arguments for and against the building of chemical factories.

neutralisation

Starter 1, Exploring 1, Explaining 1, Explaining 3, Plenary 1, Homework 1

Could

Some pupils could: give a balanced evaluation of the arguments for and against the construction of new chemical facilities.

Starter 1, Starter 2, Exploring 4, Explaining 3, Plenary 2, Exploring 2 (as homework)

Task

Level

NC

Type

Objectives

Skills

1 KC

2 KP

3 RC

4 CO

Starter 1

S

46

Classwork

PLTS (Rl, Ct)

2c

Starter 2

S

56

Classwork

1, 5

PLTS (Ct)

1a

1c

2c

a

Exploring 1

M/S

45

Practical

1

PLTS (Ep)

1a

1a, 1c, 2a

2c

a, f

Exploring 2

C

56

Classwork

1, 3, 5

Lit (EC), PLTS (Rl)

2b

2c

Exploring 3

S

46

Classwork

1, 2, 4, 5

ICT (MS

1a, 1b

3a

2c

Exploring 4

C

47

Practical

1, 3

PLTS (Ep, Tw),

Num (M), Lit (EW)

1b

1a, 1b, 1c, 2a

2c

a, c

Exploring 5

M/S

46

Classwork

1, 5

Lit (WF)

2c

Explaining 1

M/S

46

Classwork

1, 3, 5

2c

c

Explaining 2

C

57

Practical

1

Num (L)

1a

1c,

2c

a

Explaining 3

M/S

46

Classwork

2, 6, 7

Lit (DS)

2a, 2b

3a

4c

a, c, d, j

Plenary 1

S

46

Classwork

all topics

PLTS (Rl)

2c

Plenary 2

M/S

45

Classwork

1, 3, 5,

Lit (WF)

2c

Plenary 3

C

57

Classwork

2, 6, 7

Lit (EW), PLTS (Ep)

2a, 2b, 4a

4c

a, c, d, e, j

Plenary 4

M/S

47

Classwork

2, 6, 7

Lit (EW)

2a, 2b, 4a

4c

c, d, j, k

Plenary 5

M/S

46

Classwork

whole unit

PLTS (Rl)

2c

Plenary 6

M/S

46

Classwork

whole unit

PLTS (Rl)

2c

Plenary 7

M/S

47

Classwork

whole unit

PLTS (Rl, Sm)

Homework 1

S/C

46

Homework

1, 5

1a

1a, 1b, 2a

2c

c

Homework 2

S

46

Homework/ Practical

1, 5

PLTS (Ie)

1a

1a, 1b, 1c, 2a, 2b, 3a

2c

a, c

This unit introduces ideas about acids, alkalis and indicators

in the context of acid manufacture. There is also an introduction to ideas about risk assessment and hazard classification.

We recommend between 7.5 and 10 hours of teaching time for this unit.

(L4) Recognise that people who deal with acids or alkalis have strict

safety rules.

SHOULD

2 Yr KS3

PB pages

7476

7Ee Starter 1

7Ee Exploring 1

7Ee Explaining 1

7Ee Explaining 3

7Ee Exploring 2

7Ee Plenary 1 (as

homework)

7Ee Plenary 7

Most pupils should:

(L5) Describe some of the arguments for and against industrial development in a particular area.

(L6) Recognise that the modern understanding of acids and alkalis

is based on work from many scientists, including Arabic scientists.

From KS2 most pupils will:

know that solids remain in the solution when they dissolve

know that there is a limit to how much solid will dissolve in a liquid

know about several variables which affect the rate at which a solid will dissolve

know that some materials can be dangerous.

This unit builds on ideas introduced in the QCA Scheme of Work

for KS2: Unit 6C More about dissolving and Unit 6D Reversible and irreversible changes.

Some pupils could:

(L7) Evaluate the conflicting evidence for competing theories about acids.

(L7) Give reasons for why you agree or disagree with others when

discussing the arguments for and against industrial development in an area.

Key processes

At the end of this unit

All pupils must:

(L4) Carry out a fair test.

(L4) Present results in table and bar charts. (L5) Work safely with dilute acids and alkalis.

(L5) Use an indicator to work out if something is acidic, alkaline or

neutral.

The linking theme for this unit is the manufacture, transportation

and uses of acids. The manufacture of sulphuric acid is used to

show how hazards are classified, the care needed in transportation and storage of chemicals and the need to monitor the environment. The uses of weak acids are introduced through the familiar context

of food and drink. The aim throughout is to build up the more abstract ideas from contexts, applications or ideas with which the pupils are already confident, or where the relevance should be readily apparent.

Most pupils should:

(L5) Use a knowledge of acids and alkalis to identify questions that can be investigated and suggest appropriate data to collect.

(L5) Identify relationships in data.

(L6) Recognise hazard warning symbols and act accordingly (maybe using secondary sources to find out the dangers).

(L6) Describe how to lessen the risks of working with acids and alkalis.

(L6) Explain how conclusions match evidence. (L6) Suggest how a method can be improved.

Some pupils could:

(L7) Evaluate your own work and that of others to see whether you can make valid comparisons between the different sets of results.

Topic 7Ea uses the manufacture and transport of acids to

introduce ideas about hazard warning classifications as used in the laboratory and for the transportation of chemicals.

Topic 7Eb introduces the idea that many familiar and non- hazardous substances are classified as acids, and that these non- hazardous acids can be identified by their taste.

Topic 7Ec introduces acids and alkalis with a practical definition based on their effect on indicators. The practical and historical approach is sustained through the introduction to alkalis.

Topic 7Ed progresses from this concrete experience of acids and alkalis to the more theoretical concepts of pH, substance classification and acid strength, by looking at how our understanding of the nature of acids has changed over time. In

both Topics 7Ec and 7Ed, familiar substances encountered in the home are used as a context to introduce new scientific ideas. Practical work covers ideas about blind testing in an investigation where only subjective results can be obtained.

Topic 7Ee looks at some applications of neutralisation in more detail, and includes investigations of the way that pH changes when an acid is added to an alkali. Pupils can apply their ideas on neutralisation to a practical homework on making sherbet, giving a return to the theme of food and drink. There is also the

opportunity for pupils to carry out an investigation for Attainment Target 1 to find out which of a range of indigestion cures is most effective. The topic ends with a look at why manufacturing plants are situated in particular areas, offering pupils the chance to engage in debate about the possible impact of a development in their local area.

Range and content


All pupils must:

(W4) Name something that is an acid.

(L4) Describe differences between acids and alkalis. (L4) List some common uses of acids and alkalis.

Most pupils should:

(L5) Be able to classify solutions as acidic, alkaline or neutral using indicator colours and pH values.

(L6) Explain what happens to pH during neutralisation. (L6) List some common uses of neutralisation.

Some pupils could:

(L7) Link the pH of an acid or alkali to its hazards.

For a list of updated and vetted websites that can be used to

support your teaching of this unit please visit the Exploring Science: How Science Works E-Forum HYPERLINK http://groups.google.co.uk/group/exploringscience (http://groups.google.co.uk/group/exploringscience).

Expectations

Key concepts


All pupils must:

(L4) Recognise that different people will have different views on the development of an industrial site.

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Pearson Education Limited 2008

Acids and alkalis

7E

7E NC statements covered

From KS2

4 Curriculum opportunities

COULD

PB pages

7476

Starter 1

Starter 2

Exploring 4

Explaining 3

Plenary 2

Exploring 2 (as

homework)

At KS3

1 Key concepts

2 Key processes

Skills opportunities for Personal, Learning and Thinking Skills (PLTS),

literacy, numeracy and ICT are included in the individual topic notes.

3 Range and content

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7EAcids and alkalis

Framework statements covered by Unit 7E

1 How Science Works

1.1 Explanations, arguments and decisions

SHOULD

PB pages

7476

Starter 1

Exploring 1

Explaining 1

Explaining 3

Plenary 1

Plenary 7

Homework 1

1.2 Practical and enquiry skills

3 Chemical and material behaviour

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7E Routes through the unit

This page suggests routes through the unit at three different levels, using some of the tasks provided. Many other teaching sequences are possible using the alternative teaching materials and tasks provided or

by adding your own materials. We recommend between 7.5 and 10 hours of teaching time for this unit.

Acids and alkalis

7E

MUST

PB pages

7476

Starter 2

Exploring 1

Explaining 1

Plenary 2

Plenary 7

Homework 2

129


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7EAcids and alkalis

7E Background information

7Ea Acids in action/Diamonds are for safety

Many acids and alkalis are classified as either irritant or corrosive depending on the concentration. This means that appropriate care must be taken when handling them.

and accurate at this level, with power having the dual meaning

of strength as well as its mathematical sense as in power of ten. The recognition that hydrogen was the distinguishing feature of

an acid was a far from obvious one, and to this day we have the reminder of the erroneous theory that oxygen (= acid maker) was the relevant element. The fact that these theories of acid behaviour were being developed at the same time as the oxygen/phlogiston debate was at its height means that these theories are intimately intertwined.

Number and title

Level

Location

Type

Tasks

Finding the balance

Must/Should

PB p7475

Classwork

Explaining 1

Not in my back yard?

Must/Should

PB p76

Classwork

Explaining 3

7E

Quick Quiz

Must/Should

ASP

Classwork

Plenary 5

7E

Quick Quiz Answer Sheet

Must/Should

ASP

Classwork

Plenary 5

7E

End of Unit Test

Must/Should

ASP

Classwork

Plenary 6

7E

Level Ladder

Must/Should

ASP

Classwork

Plenary 7

7Ee

Quick Check

Must/Should

ASP

Classwork

Plenary 1

7Ee

Word Sheet

Should

ASP

Homework

7Ee(1)

Finding the balance

Must

CHAP

Access

Explaining 1

7Ee(2)

Rainbow fizz

Must/Should

CHAP

Practical

Exploring 1

7Ee(3)

Rainbow fizz results sheet

Must

CHAP

Practical

Exploring 1

7Ee(4)

Indigestion 1

Must/Should

CHAP

Practical

Exploring 4

7Ee(5)

Indigestion 2

Should

CHAP

Classwork

Exploring 2

7Ee(6)

Reverseword

Must/should

CHAP

Classwork

Exploring 5

7Ee(7)

Where do you build it?

Must/Should

CHAP

Classwork

Plenary 4

7Ee(8)

Making sherbet 1

Must/Should

CHAP

Homework

Homework 1

7Ee(9)

Making sherbet 2

Must/Should

CHAP

Homework

Homework 2

This is usually done by consulting and, if necessary, adapting

model standard risk assessments provided by employers. In most instances this will be information provided by organisations such as CLEAPSS or the ASE.

Principles of risk management include:

The description universal indicators is used deliberately to try to

counteract the idea that there is one substance called Universal Indicator. Universal (or full range) indicators are a class of mixtures which are made from blends of individual indicators. The type

used in schools has the majority of its colour changes in the pH

range 411: it is therefore well suited to classifying substances on

a five-point descriptive scale (strong acid/weak acid/neutral/weak alkali/strong alkali). For more specialised purposes (e.g. soil testing)

a narrow range indicator may be appropriate, e.g. with five or six distinct colours within the range pH 5.0 to 8.0.

consideration of whether a safer alternative substance or

procedure may be substituted

reducing the amount of hazardous substance used, for

example by reducing the scale of an experiment or using a less concentrated solution

taking appropriate precautions, e.g. use of fume cupboards, eye protection.

A common error by pupils and others is to assume that because

acids are dangerous, alkalis are safe. In fact, for solutions of equal concentration, alkalis are usually more dangerous than acids.

7Ee Finding the balance/Not in my backyard?

The precise definition of pH is - log [H+], where [H+] is the

hydrogen ion concentration in moles per cubic decimetre. The product of the hydrogen ion and hydroxide ion concentrations

is about 10-14 at 25 C. At the neutral point the hydrogen and hydroxide ion concentrations are equal at 10-7 (hence pH 7 is neutral). While even the highest-attaining pupils will not need anything like this depth of treatment, the main implications for the teaching at this level are that:

Further reading

A more extended treatment of the acid bath murders is given in

Richard Hart Chemistry Matters, pages 208209 (OUP, 1978).

7Eb Tangy tastes

The definition of an acid has changed over time. The accepted definition that is most useful for KS3 teachers is that acids are substances which dissolve in water to give solutions containing hydrogen ions (H+). The development of these ideas is taken further in Topic 7Ed.

the choice of the numbers 1 to 14 is not random some more

enquiring pupils may be satisfied with the explanation that it is linked in some way to the amount of hydrogen

changing the dilution of an acid or alkali by a factor of ten will alter the pH by one unit (this is the effect of choosing a logarithmic scale)

addition of a small amount of acid or alkali near the neutral point can have quite a large effect on the pH, whereas adding the same amount to a strong acid or alkali will have very little effect.

The sharp taste of acids is used as a starting point for identifying

acids in this topic. The English word sour derives from the same root as the German sauer meaning acid (as in sauerkraut).

7Ec In the red/Making an ash of it

Indicators are themselves weak acids or bases, which can gain

or lose hydrogen ions depending on the pH of the solution. This change in structure also causes a change in colour. The precise pH

at which this colour change occurs varies from indicator to indicator. Most indicators have two main colours, and an intermediate

colour which is the result of colour mixing. For example, the purple colour of neutral litmus solution is a result of a mixture of equal concentrations of the red (acidic) and blue (alkaline) forms. Litmus changes colour at about pH 7 and is therefore particularly well

suited to elementary work.

When fuels based on plant materials are burned, the non-metals

oxidise to volatile oxides. The solid ash left at the end of the fire will consist of the metal oxides mainly potassium and magnesium,

which were originally absorbed by the plant from the soil. These oxides are alkaline in nature, and the Pupils Book emphasises the

link between the original discovery of this property and our current use of the word alkali. It is also the source of the symbol K for potassium the first letter of the name Kali in Arabic, or the Latin equivalent Kalium (it is also Kalion in Greek). The reaction of alkalis with fats and oils to make soap is also considered. This is one

reason why concentrated alkalis are so corrosive: they start to react with the natural oils in your skin to turn them into soap.

7Ed Mixing a rainbow/Focus on the H factor

The strength of acids and alkalis is linked to the concentration of hydrogen ions in solution. Although the origin of the phrase is Danish (potenz, meaning power in Danish and German) the use

of power of hydrogen to explain the meaning of pH is logical

130

Exploring Science

edition


Task

Level

NC

Type

Objectives

Skills

1 KC

2 KP

3 RC

4 CO

Starter 1

M/S

45

Classwork

PLTS (Ct, Rl)

2c

Starter 2

S

45

Classwork

5, 7

PLTS (Ct)

1a

1a

2c

a

Exploring 1

M/S

35

Practical

1, 2, 4, 5

PLTS (Ep, Tw)

1a, 1b, 2a

2c

Exploring 2

M/S

35

Classwork

1, 2, 4, 5

2a

2c

Exploring 3

C

46

Practical

1, 4, 5

PLTS (Ep, Tw)

1a

1a, 1c, 2a

2c

a

Exploring 4

S

45

Classwork

1, 4, 5

PLTS (Ct)

2c,

a

Exploring 5

S/C

56

Practical

1, 4, 5, 7

PLTS (Ct)

1a

1a, 1c, 2a, 2b

2c

a, f

Exploring 6

S/C

57

Classwork

3, 6,

Lit (EC), PLTS (Tw, Ep)

1b, 3a

2c

h

Explaining 1

S/C

57

Classwork

1, 2, 4, 5

PLTS (Rl)

2a

2c

b, c

Explaining 2

M/S

45

Classwork

3, 6, 8

3a

2c

h

Plenary 1

S

46

Classwork

1, 2, 4, 5

PLTS (Ct, Rl)

2c

Plenary 2

S

46

Classwork

1, 2, 4, 5

PLTS (Ct)

2c

Plenary 3

M

45

Classwork

1, 2, 4, 5

Lit (WF)

2c

Homework 1

M

4

Homework

1, 2, 4

2c

c

Homework 2

S

56

Homework

7

PLTS (Ct)

1a, 1b

2a

2c

Homework 3

C

58

Homework

6

Lit (Ew)

1c

2c

b, c

COULD

PB pages

7073

Starter 2

Exploring 1

Exploring 3

Exploring 4

Explaining 2

Plenary 2

Homework 3

MUST

PB pages

7073

Starter 1

Starter 2

Exploring 2

Explaining 2

Plenary 1

Homework 1

SHOULD

2 Yr KS3*

PB pages

6873

7Ec Starter 1

7Ec Exploring 2

7Ec Explaining 1

7Ec Explaining 2

7Ed Explaining 1

7Ed Exploring 1

7Ed Plenary 2

7Ed Homework 2

SHOULD

PB pages

7073

Starter 1

Starter 2

Exploring 1

Exploring 2

Explaining 2

Plenary 2

Homework 2

Pupils materials

Number and title

Level

Location

Type

Tasks

Mixing a rainbow

Must/Should

PB p7071

Classwork

Explaining 1

What is an acid?

Should/Could

PB p7273

Classwork

Explaining 2

7Ed

Quick Check

Must/Should

ASP

Classwork

Plenary 1

7Ed

Word Sheet

Must/Should

ASP

Homework

7Ed(1)

Mixing a rainbow

Must

CHAP

Access

Explaining 1

7Ed(2)

The H factor

Must/Should

CHAP

Access

Explaining 2

7Ed(3)

pH testing 1

Must

CHAP

Practical

Exploring 1

7Ed(4)

pH testing 2

Should

CHAP

Practical

Exploring 1

7Ed(5)

Arguments about acids 1

Should

CHAP

Classwork

Exploring 6

7Ed(6)

Arguments about acids 2

Could

CHAP

Classwork

Exploring 6

7Ed(7)

Making a pH chart

Must

CHAP

Homework

Homework 1

7Ed(8)

More about indicators

Should

CHAP

Homework

Homework 2

7Ed(9)

pH balanced products

Could

CHAP

Homework

Homework 3

SS14

Thinking Skills

Should

CHAP

Skills Sheet

Exploring 4, Plenary 2

Objectives

All pupils must:

(1) realise that acids can be hazardous

(2) work safely with dilute acids

(3) be able to deal with acids and alkalis if they are splashed on the skin

(4) describe some hazard warnings used on laboratory chemicals and road tankers.

Correctly use the words acid, alkali.

Most pupils should:

(5) describe what is mean by a risk assessment

(6) identify the hazard warning symbols for corrosive and irritant substances

(7) describe how dilution with water can reduce the hazard of an acid or alkali

(8) give the names of the three common laboratory acids:

sulphuric acid, nitric acid and hydrochloric acid

(9) give some examples of the uses of acids

(10) use the Hazchem code to identify the hazards of chemicals.

Correctly use the words corrosive, hydrochloric acid,

irritant, nitric acid, risk assessment, sulphuric acid.

Some pupils could:

(11) describe in detail how the Hazchem code is used by the emergency services.

Exemplar topic plans

* This table is repeated in 7Eb.

Topic notes

Targets for the topic can be accessed via the ActiveBook or

ActiveTeach from the link next to the initiator question.

131


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7EaAcids in action

Topic task planner

Use these tasks to adapt the exemplar topic plan to your own needs. Many tasks can be adapted to become different types (e.g. starter

rather than exploring). AT or AB/AT at the top of a task means that the task depends on using the ActiveBook and/or ActiveTeach;

where these symbols appear in brackets it indicates that the task can be carried out with or without their use.

Task

Level

NC

Type

Objectives

Skills

1 KC

2 KP

3 RC

4 CO

Starter 1

S

46

Practical

1

PLTS (Ct)

1a

1a

2c

a

Starter 2

All

Classwork

2

PLTS (Rl)

2c

Exploring 1

M/S

45

Practical

26

PLTS (Ep, Tw)

1b

1a, 1b, 2a,

2c

a

Exploring 2

M/S

45

Classwork

1, 2, 3, 6, 7

PLTS (Ep)

1b

2a

2c

Exploring 3

All

46

Classwork

6

PLTS (Ct)

1b

2a, 2b

2c

Explaining 1

S

45

Classwork

1, 2, 3

1b

2c

Explaining 2

S

45

Classwork

1, 2, 3, 5, 6, 7

3a

2c

h

Plenary 1

M

45

Classwork

1, 5

Lit (WF)

2c

Plenary 2

M

45

Classwork

2, 3, 6, 7

Lit (WF)

2c

Plenary 3

M/S

45

Classwork

13, 8

Lit (WF), PLTS (Ct, Rl)

2c

Plenary 4

All

45

Classwork

13, 58

PLTS (Ct)

2c

Homework 1

All

45

Homework

13, 68

PLTS (Ie)

1a, 1b

1a, 1b, 1c,

2a, 2b

2c

a, c, e

Homework 2

S/C

46

Homework

13, 68

Lit (RR), ICT (PS), PLTS (Tw)

2a, 3a

2c

a, c

is likely to be written off) about one third to one half full with

granulated sugar. Pour concentrated sulphuric acid over it so that

it just covers the sugar. The sugar will darken immediately. Stir the mixture carefully and leave it to stand the reaction will become more vigorous after about a minute. Black carbon is formed, and the reaction is sufficiently exothermic to turn the water that is

formed into steam, which pushes the sugar up out of the beaker in

a black, sausage-shaped foam, which then hardens.

Starters

1: Quick Quiz

Afl

Use the 7E Quick Quiz for baseline assessment for this unit.

Pupils could record their answers on the 7E Quick Quiz Answer

Sheet.

2: Acids brainstorm

Ask pupils to brainstorm hazards associated with acids and other chemicals. Draw up a list of key words on the board and save them

to be returned to later in the topic or unit.

Paper towels placed in a beaker of concentrated sulphuric acid will

blacken very quickly the beaker will get warm. You could also demonstrate the action of acid on cotton.

This demonstration should be carried out in a fume cupboard because of the production of carbon monoxide (extremely flammable and toxic) and sulphur dioxide (toxic)

as possible by-products in the reaction. Concentrated sulphuric acid is corrosive.

3: Hazard symbols AT

The second AT presentation link on page 64 opens Hazard warning labels. Ask pupils to match the symbol to the hazard,

or rank the hazards in order from least to most harmful. Use this to stimulate a discussion on whether a flammable substance is more or less harmful than, say, a toxic one. This could also lead to discussion on why different acids and alkalis have different hazard labels, and suitable safety procedures for working with them (e.g.

eye protection).

Resources

Jam jar or 250 cm3 beaker; granulated sugar; concentrated sulphuric acid (corrosive); glass rod; fume cupboard. Optional: paper towels; piece of cotton material.

4: Uses of sulphuric acid AT

Ask pupils to think about why we need to make sulphuric acid. The AT video link on page 63 opens Chemical plants introducing the health and safety officer and his role at the plant together with a summary of what the plant produces and the key uses. Ask pupils

to recall the key points about safety from what they have seen.

Exploring tasks

1: What hazard? AT

The AT animation link on page 65 opens How dangerous are these acids? photos of a number of different acids at varying concentrations. By hovering over the relevant acid, the associated

hazard symbol (corrosive, irritant or low hazard) appears. Pupils can deduce how concentration affects hazard classification and compare the hazards posed by different acids.

5: Demonstration: Action of concentrated sulphuric acid

This is a spectacular demonstration of the effect of a corrosive substance on everyday materials. Fill a beaker (or jam jar it

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Acids in action7Ea

2: Thinking about dilution (AT)

PMI: only dilute acids should be allowed. (Possible answers:

P the hazards of concentrated acids would be removed, murderers would not be able to dissolve bodies!; M it would be much more expensive to transport acids; I are some concentrated acids more dangerous than others?)

The first AT presentation link on page 65 opens Thinking about dilution a PowerPoint presentation version of this task.

For pupils who might find it difficult to cope with the question in

this open-ended form, you could present several graph types and ask them to discuss which would best match the statement.

2: Pupils Book page 6465 (AB/AT)

Worksheet 7Ea(1) is the Access Sheet.

COULD

PB pages

6869

Starter 1

Explaining 1

Exploring 1

Explaining 2

Plenary 3

Plenary 4

Homework 1

The AT video link on page 65 opens the video Dealing with

hazards this shows how safety officers deal with spillages within

a factory.

3: Practical: Comparing acids

Pupils compare the hazardous nature of different acids by reference to simple observations linked to chemical reactivity.

The third AT presentation link and the document link on page

64 open Handling acids which prompt pupils to design a presentation poster about handling acids safely.

Must: only three acids are used, and the tests are restricted to

those that can give a clear visual indication. The instructions are on Worksheet 7Ea(2).

Should: instructions are given on Worksheet 7Ea(3). Pupils use another acid and a more subtle test (the reaction with

sodium hydroxide solution) is introduced. Given the corrosive nature of sodium hydroxide if it is at a concentration likely to give a measurable temperature rise, this version should only be attempted if you are confident of the practical abilities and

behaviour of the group. If digital temperature probes capable of reading to 0.1 C are available, this may allow the concentration of the sodium hydroxide to be reduced to 0.4 mol dm3 (irritant)

while still getting useful and observable results. An alternative would be to set up four temperature probes linked to a datalogger for this part of the experiment, which would then effectively become a demonstration.

Could: present pupils with extracts from the relevant CLEAPSS Student Safety Sheets, and ask them to discuss the risks involved before starting any practical work.

1 mol dm-3 sodium hydroxide is corrosive. Eye protection should

be worn.

3: Comparing the hazards

Worksheet 7Ea(4) asks pupils to use the results of experiments to compare reactions and hazards, and draw conclusions. It also

reinforces pupils knowledge of what a fair test is.

Plenaries

1: Thinking about hazards (AT)

PMI: all chemicals should have hazard labels. (Possible answers:

P it would be more obvious if the chemical is hazardous or not;

M more hazardous chemicals might be less obvious; I who invented the hazard labels? When were these labels introduced?)

The third AT presentation link on page 65 opens Thinking about hazards a PowerPoint presentation version of this task.

2: Hazards matching

Worksheet 7Ea(5) allows pupils to summarise key learning on hazards through a matching activity. This could be developed into

a projected resource and pupils could carry out the matching on screen. As an extension, ask pupils to rank the symbols in order from least to most harmful. There is no one correct answer to this ranking exercise, as the dangers of a particular chemical depend

on its circumstances for instance, something that is poisonous may be completely harmless in the context of a spill, and some flammable substances can be consumed (e.g. alcohol!).

Resources (per group)

Must: test tube rack plus at least 3 test tubes; 3 pieces of magnesium ribbon (about 1 cm length); 3 marble chips (small enough to fit comfortably into the test tube); thermometer; dilute hydrochloric acid at concentrations

1 mol dm-3, 0.1 mol dm-3 and 0.01 mol dm-3 labelled (at random) X, Y and Z; Worksheet 7Ea(2).

Should: as for Must level, plus: hydrochloric and ethanoic acids

at concentrations of 0.5 mol dm-3, 1 mol dm-3 and 2 mol dm-3; sodium hydroxide solution (1 mol dm-3); eye protection;

thermometers or digital temperature probes; Worksheet 7Ea(3).

Resources

Worksheet 7Ea(5); access to glue and scissors.

3: Summarising ideas on hazards

Pupils Book question 6 on page 65 allows pupils to summarise their ideas on hazards.

4: Acid bath murders

Ask pupils to find out more about the acid bath murders and present their findings in the form of a presentation to the rest of the class.

4: I can cloze exercise AB/AT

Afl

The second AT document link on page 65 opens a cloze

exercise covering the material on pages 6465. There is also an AT

presentation version with answers.

Resources

Library/internet access.

5: Quick Check

5: Acid spills AB/AT

The first AT document link on page 65 opens Acid spills a document that can be used as a stimulus to get pupils thinking about what would happen if a there were an accident in the

locality. If there is a genuine local incident that can be drawn upon through local news reports this would obviously add immediate

interest. This could then link to Homework 2.

Afl

The Quick Check sheet for this topic asks pupils to use their

experience of laboratory work at KS2 and from this topic to identify

safety hazards in the laboratory through a cartoon of unsafe practices.

Homework tasks

1: Worksheet 7Ea(6) is a write-on sheet on the Hazchem code.

2: Worksheet 7Ea(7) contains more complex questions on the

Hazchem code.

3: Question 7 on page 65 of the Pupils Book could be used as a homework task in extended writing.

Explaining tasks

1: Pupils Book page 63

Question 3 encourages pupils to think about translating a comparative statement into graphical form. A graph with a positive

correlation would be expected if the statement were true.

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Starter 1

Explaining 1

Exploring 1

Explaining 2

Plenary 1

Homework 1

SHOULD

2 Yr KS3*

PB pages

6873

7Ec Starter 1

7Ec Exploring 2

7Ec Explaining 1

7Ec Explaining 2

7Ed Explaining 1

7Ed Exploring 1

7Ed Plenary 2

7Ed Homework 2

SHOULD

PB pages

6869

Starter 1

Starter 2

Explaining 1

Exploring 1

Explaining 2

Plenary 3

Homework 1

Number and title

Level

Location

Type

Tasks

In the red

Must/Should

PB p68

Classwork

Explaining 1

Making an ash of it

Must/Should

PB p69

Classwork

Explaining 2

7Ec

Quick Check

Must

ASP

Classwork

Plenary 3

7Eb

Word Sheet

Must

ASP

Homework

7Ec(1)

In the red

Must

CHAP

Access

Explaining 1

7Ec(2)

Making an ash of it

Must

CHAP

Access

Explaining 2

7Ec(3)

Red cabbage indicator

Must/Should

CHAP

Practical

Exploring 1

7Ec(4)

Red cabbage: methods and techniques

Must/Should

CHAP

Practical

Exploring 1

7Ec(5)

The litmus test 1

Must/should

CHAP

Classwork

Exploring 3

7Ec(6)

The litmus test 2

Must

CHAP

Classwork

Exploring 3

7Ec(7)

Indicators at home 1

Must

CHAP

Homework

Homework 1

7Ec(8)

Indicators at home 2

Should

CHAP

Homework

Homework 1

7Ec(9)

Alkalis in action

Could

CHAP

Classwork

Homework 2

SS12

Thinking Skills

All

CHAP

Skills Sheet

Plenary 4

Pupils materials

Task

Level

NC

Type

Objectives

Skills

1 KC

2 KP

3 RC

4 CO

Starter 1

M/S

46

Classwork

15

PLTS (Ep)

2c

a, c

Starter 2

M/S

56

Classwork

15

1b

2c

c, k

Exploring 1

M/S

36

Practical

14

PLTS (Ep, Tw)

1b

1a, 1b, 1c, 2a

2c

c, k

Exploring 2

M/S

Classwork

1, 2, 3

2a

2c

c, k

Exploring 3

M/S

Classwork

1, 3, 4

Lit (WF)

2c

c

Exploring 4

S/C

57

Classwork

5

Num (T,C,L)

1b

2a, 3a

2c

Exploring 5

C

57

Classwork/ Homework

3, 6

Lit (RR), ICT (PS), PLTS (Tw)

3a

2c, 4c

b

Explaining 1

M/S

47

Classwork

3

2c

Explaining 2

M/S

Classwork

2, 3

PLTS (Ct)

2c

c, k

Explaining 3

C

57

Classwork

2c

c, k

Plenary 1

M

45

Classwork

1, 2, 3, 4

Lit (WF)

2c

Plenary 2

M/S

45

Classwork

2

PLTS (Rl)

2c

Plenary 3

M/S

Classwork

14

PLTS (Ct)

3a

2c

Homework 1

All

45

Homework

3, 5

Lit (WF, RR), ICT (PS)

3a

2c

c

Objectives

All pupils must:

(1) state that acids have a sour or sharp taste.

Correctly use the word acid.

Most pupils should:

(2) state that vinegar and citrus fruits are acidic

(3) identify some everyday uses of acids, for example in preserving foods

(4) describe how some acids used in the home are less hazardous than those used in laboratories.

Some pupils could:

(5) carry out detailed research into the positive and negative effects of acids in the home and in the environment.


Topic notes



* This table is repeated in 7Ea

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Tangy tastes7Eb

Topic task planner

Use these tasks to adapt the exemplar topic plans to your own needs. Many tasks can be adapted to become different types (e.g. starter


where these symbols appear in brackets it indicates that the task can be carried out with or without their use. Also consider using one of the plenaries from the previous topic as a starter task in this topic.

SHOULD

2 Yr KS3*

PB pages

6367

7Ea Starter 1

7Ea Starter 4

7Ea Exploring 2

7Ea Exploring 1

7Eb Starter 2

7Eb Exploring 3

7Eb Exploring 2

7Eb Explaining 2

7Eb Plenary 2

7Eb Exploring 5

(as homework)

This experiment is best done in the food technology room

or the dining area. If a laboratory has to be used then the

exceptional nature of this practical should be emphasised. Wipe down all benches and lay out paper towels to create clean areas. All bottles of chemicals must be removed from the laboratory beforehand.

Starters

1: Acids discussion

Ask pupils to discuss the statement All acids are dangerous.

Collect ideas or take a vote. This could be revisited later in the topic.

2: Acid sampling

Ask for a brave volunteer who is prepared to sample an acid in front of the class. Reward the volunteer with an acid drop or sherbet lemon sweet, and asked them to describe the taste. If done in a laboratory, take care to ensure that there is no contact

between sweets and surfaces pupils should be reminded that this

is an exception to a general rule. This could then lead in to a more general discussion about foods and drinks that contain acids.

Resources (per group or class, depending on

the method used)

Set of clean, disposable plastic drinking cups containing a selection of liquids (vinegar, salt water, tonic water, lemon juice, fizzy orange, milk, sugar water) labelled L1, L2, L3, etc; plastic drinking straws one per pupil per cup; blindfold; Worksheets

7Eb(2) and 7Eb(3).

2: Drink ingredients AT

The second AT presentation link on page 66 of the Pupils Book opens Drink ingredients an activity in which pupils are presented with pictures of ingredients of some popular drinks. Ask pupils to

list the acids they contain.

Exploring tasks

1: Practical: Taste tests

This activity depends on being able to carry out the test under hygienic conditions. Working in pairs or small groups, pupils take

a blind test in which they are asked to describe and identify a number of liquids. The liquids could be stored in plastic drinking cups, and dispensed using the end of a drinking straw (which

is easily disposable if it becomes contaminated). Include some liquids which are acidic, as well as a range of contrasting tastes.

Alternatively, you could dispense the liquids to pupils while they are working on another written task.

3: Acid or not acid? AT

The AT animation link on page 67 of the Pupils Book opens Acid

or not acid? audio files in which young people describe

how certain substances taste. Ask pupils to decide acid or

not acid?

4: Data analysis: Reaction of limestone and acid

Ask pupils to carry out a data analysis on results from an

experiment in which limestone chips are reacted with the acid in a fizzy drink provided on Worksheet 7Eb(4). This activity develops numeracy skills in calculation and graph plotting. Pupils are asked

to analyse critically the results of the experiment and whether conclusions drawn are valid.

Must: pupils use the framework on Worksheet 7Eb(2) to record

their results.

Should: Worksheet 7Eb(3) provides guidance but pupils design their own table for recording results.

Could: Worksheet 7Eb(3) provides an extension activity where pupils explore which areas of the tongue are most sensitive to acids.

5: Investigating applications of acids

Group work task pupils use Worksheet 7Eb(7) as a prompt to help them investigate an aspect of the applications of acids and present the work back to the class. This could also be set as a homework task.

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7EbTangy tastes

Explaining tasks

1: Pupils Book pages 6667

This explains the use of acids in foods and drinks, including coverage of taste, health issues, food preservation and food labelling. Worksheet 7Eb(1) is the Access Sheet. Use photo F on page 67 as a stimulus to discuss the similarities and differences between vinegar and non-brewed condiment.

SHOULD

PB pages

6667

Starter 1

Starter 2

Exploring 4

Exploring 2

Explaining 1

Explaining 2

Plenary 2

Plenary 3

Homework 1

The first AT document link on page 67 opens True or false?

a sequence of sentences for pupils to identify mistakes in.

2: Scurvy

Ask pupils if they know why British sailors used to be known as

limeys. Pupils could discuss their answers and use the information on Pupils Book page 66 to check their understanding.

3: Whats in a name?

Show samples of various vinegars, non-brewed condiment, dilute and concentrated ethanoic acid. Explain that everyday terms are

not the same as scientific ones, and that as the context for our understanding about acids changes, so do the names, e.g. vinegar/ acetic acid/ethanoic acid according to context, and different names historically such as methane carboxylic acid, acetyl hydroxide, hydrogen acetate.

Plenaries


Afl


exercise covering the content of pages 6667. There is also an AT


2: Quick Check

The Quick Check sheet requires pupils to use a selection of letters to come up with the names of a number of acids studied in this topic.

3: Thinking about acids around us (AT)

OOO: water, vinegar, orange juice. (Possible answers: water is the only neutral substance or not an acid.)

PMI: no substances should be acids. (Possible answers: P

we would not be harmed by acids; M alkalis could not be neutralised, foods would go off more easily, things would taste boring; I how would our stomachs kill harmful bacteria?)

The second AT presentation link on page 67 opens Thinking about acids around us a PowerPoint presentation version of this task.

Homework tasks

1: Pupils find out which products in their homes are acids and

display their results in an appropriate format.

Must: Worksheet 7Eb(5) is a very structured worksheet which requires very simple responses.

Should: Worksheet 7Eb(6) provides structured advice on what

to look for, but a more open-ended choice of materials and formats.

Could: Worksheet 7Eb(7) pupils work in groups and coordinate their research so that each group member has a specific role and/or has responsibility for a particular content area (see also Exploring 6).

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PB pages

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Starter 2

Exploring 4

Exploring 2

Explaining 1

Explaining 2

Plenary 1

Homework 1

COULD

PB pages

6667

Starter 2

Exploring 5

Exploring 3

Explaining 1

Explaining 3

Exploring 1

Plenary 3

Exploring 5 (as

homework)

Number and title

Level

Location

Type

Tasks

Tangy tastes

Must/Should

PB p6667

Classwork

Explaining 1

7Eb

Quick Check

Must/Should

ASP

Classwork

Plenary 2

7Eb

Word Sheet

Must/Should

ASP

Homework

7Eb(1)

Tangy tastes

Must

CHAP

Access

Explaining 1

7Eb(2)

Taste tests 1

Must

CHAP

Practical

Exploring 1

7Eb(3)

Taste tests 2

Should/Could

CHAP

Practical

Exploring 1

7Eb(4)

Acid corrosion

Should/Could

CHAP

Classwork

Exploring 4

7Eb(5)

Acids all around 1

Must

CHAP

Homework

Homework 1

7Eb(6)

Acids all around 2

Should

CHAP

Homework

Homework 1

7Eb(7)

Acids all around 3

Could

CHAP

Homework

Exploring 5, Homework 1

SS12

Thinking Skills

Must/Should

CHAP

Skills Sheet

Plenary 3

Task

Level

NC

Type

Objectives

Skills

1 KC

2 KP

3 RC

4 CO

Starter 1

All

46

Classwork

1, 4, 6, 7

PLTS (Rl)

2c

Starter 2

M

46

Classwork

1

PLTS (Ep, Rl)

1b

2c

Starter 3

S

56

Classwork

1, 2, 3, 4, 6, 10

PLTS (Ep), Lit (WF)

1b

2c

Starter 4

S

Classwork

1, 4, 5, 6, 10

PLTS (Ep)

1b

2c

c, e, i

Starter 5

M/S

Practical

1, 2, 6, 8, 9

1b

1a, 1b

2c

Exploring 1

S

5

Classwork

4, 6

1b, 2a

2c

Exploring 2

S

57

Classwork

1, 2, 3, 7

PLTS (Ct)

1b

2c

f

Exploring 3

M/S

47

Practical

19

PLTS (Ep, Tw)

1b

1a, 1b,

1c, 2a

2c

a

Exploring 4

C

57

Homework

1

Lit (RR), ICT (PS), PLTS (Sm)

2a, 3a

2c

a, b

Exploring 5

S

47

Classwork

17, 10, 11

Lit (EC)

1b, 3a

2c

c, d

Explaining 1

M/S

46

Classwork

110

3a

2b

2c

c, e

Explaining 2

M/S

46

Classwork

1, 2, 4, 5, 6, 7, 10, 11

1b,

2c

c, d, e, j

Explaining 3

C

46

Classwork

1

2a

2c

Plenary 1

M/S

Classwork

1, 4, 5

PLTS (Ct)

2c

Plenary 2

M

45

Classwork

1, 4, 5

Lit (WF)

1b

2c

Plenary 3

S

Classwork

19

Lit (RR), ICT (PS), PLTS (Tw, Rl)

1b

2c

Plenary 4

M

45

Classwork

1, 2, 4, 7

PLTS (Rl), Lit (WF)

2c

Plenary 5

M/S

Classwork

1, 2, 3, 5

PLTS (Rl)

1b

2c

Homework 1

M/S

45

Homework

1, 4, 7, 10

Lit (EC)

1b

2c

c

Homework 2

C

46

Homework

1, 4, 7, 10, 11

Lit (EC)

1b

2c

c

Homework 3

C

56

Homework

1, 4, 5, 7, 10, 11

Lit (EW), PLTS (Ct)

1b, 2a

2c

c

COULD

PB pages

6365

Starter 1

Starter 2

Explaining 1

Starter 5

Exploring 3

Plenary 1

Homework 2

Pupils materials

MUST

PB pages

6365

Starter 1

Starter 3

Starter 5

Explaining 1

Exploring 3

Plenary 2

Homework 1

Objectives

All pupils must:

(1) describe the colour change of litmus indicator with different substances

(2) explain that alkalis have the opposite effect on indicators from acids

(3) describe substances which are neither acidic nor alkaline as neutral

(4) develop skills in the use of a pestle and mortar and filtration techniques.

Correctly use the words acid, alkali, indicator, litmus,

neutral.

Most pupils should:

(5) state that most indicators are derived from plant colours

(6) critically evaluate the results of experiments with indicators

(7) explain that the neutral (purple) form of litmus is a mixture of the red and blue forms

(8) state that alkalis are at least as corrosive as acids.

Some pupils could:

(9) explain the role of Arabic scientists in developing the concept of an alkali.


* This table is repeated in 7Ed.

Topic notes



Be prepared: 7Ec

Exploring 1: red cabbage and/or other coloured substances

(e.g. beetroot, blackberries) needed.

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7EcIn the red

Topic task planner




SHOULD

2 Yr KS3*

PB pages

6367

7Ea Starter 1

7Ea Starter 4

7Ea Exploring 2

7Ea Exploring 1

7Eb Starter 2

7Eb Exploring 3

7Eb Exploring 2

7Eb Explaining 2

7Eb Plenary 2

7Eb Exploring 5

(as homework)

Worksheet 7Ec(4) is a follow-up sheet to revise the key words and

processes from the practical procedure. This could be used in class, or as a homework after the experiment has been completed. An alternative use could be as a starter activity in the next topic to reinforce prior learning.

Starters

1: Water into wine

Use the water into wine trick as a starter demonstration. Pour a beaker of water (in fact dilute sodium hydroxide solution) into an apparently empty beaker (which has a few drops of phenolphthalein indicator at the bottom of the beaker). When the alkaline solution touches the indicator, there is a change from colourless to pink/ purple. Ask pupils to speculate how the effect is achieved. Tell them that they will be able to produce similar colour transformations by

the end of the topic.

The first AT document link on page 68 opens Red Cabbage

Indicator a set of sample results which pupils are asked to add to a table.

Eye protection should be worn. There should be no tasting of food and drink (this is just after a tasting lesson!).


Part 1: red cabbage; blackberries or other strongly coloured fruit/vegetable; pestle and mortar; filter paper and funnel; access to kettle; Worksheet 7Ec(3). (If overnight storage is needed: boiling tubes/small conical flask with bung or screw cap (McCartney) bottle.)

Part 2: dropping pipettes; spotting tiles; a variety of common substances e.g. vinegar, salt, sugar, lemonade, toothpaste, lemon juice, flour, Milk of Magnesia, washing powder, scouring powder; coloured extract from part 1; eye protection.

Resources

Beaker/wine glass; dilute sodium hydroxide solution (irritant) (0.1 mol dm3); phenolphthalein indicator (highly flammable).

2: Alkali brainstorm

Ask pupils what they already know about acids, whether they have heard the word alkali before, and how you can tell the difference between acids and alkalis.

Exploring tasks

2: Experiments with litmus AT

The AT animation link on page 68 opens Experiments with litmus

a virtual experiment in which pupils move the cursor over a range of substances to find the colour of litmus (red, blue or purple).

This could either be used as a simple exercise in observation and inductive reasoning, or as a reinforcement exercise after pupils had done some initial practical work to see if they could apply their

ideas and predict what would happen in a related situation.

1: Practical: Using red cabbage as an indicator

(AB/AT)

This practical is in two parts: pupils first extract the colour from red

cabbage leaves by crushing, dissolving and filtering. The solution obtained from this process is then used to test a variety of household chemicals. The experiment could be introduced as an exercise in deductive reasoning demonstrate the effect of the cabbage juice with a named acid (e.g. hydrochloric) and then ask pupils to use the indicator to classify the substances being tested. Alternatively, you can use this task in an inductive way, with pupils first looking for colour changes. Once the results are summarised, the acids can be defined as that group of substances which turns

the indicator red. Worksheet 7Ec(3) gives all the practical instructions.

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In the red7Ec

3: The litmus test

Pupils are asked to evaluate a number of conclusions based on observations from indicator tests with litmus solution. Although the presence of water as a condition for acidic and alkaline

reactions to be shown is not a required piece of knowledge at KS3,

it is included here as an exercise in logic in a context which will

be simple enough for most pupils to understand. Allocate pupils

one of the conclusions to discuss in groups and report back to the class. After the discussion, pupils could record the findings for all the conclusions. Structured support for recording is provided by Worksheet 7Ec(6).

Homework tasks

1: After checking with an adult, pupils carry out a task at home

similar to Exploring 1 using everyday substances such as fruit juices or cold tea to make indicators. These indicators can then be tested with acids such as vinegar or lemon juice, and alkalis such as toothpaste or soap.

SHOULD

PB pages

6365

Starter 1

Starter 2

Explaining 1

Starter 5

Exploring 3

Plenary 1

Homework 1

Homework 1

Must: Worksheet 7Ec(7) offers highly structured support for

this activity in the planning, carrying out and recording of the work.

Should: Worksheet 7Ec(8) gives structured guidance on the planning, but requires pupils to produce their own written record.

Resources

Worksheets 7Ec(5) and 7Ec(6) (for Must level).

2: Worksheet 7Ec(9) asks pupils to research examples of alkalis

that are used in the home and prepare a poster, leaflet or presentation. Be aware that images downloaded from the internet may be under copyright.

Explaining tasks

1: Pupils Book page 68

This deals with the introductory ideas on indicators and their effect on acids. Worksheet 7Ec(1) is the Access Sheet.

2: Pupils Book page 69 (AT)

This deals with the concept of alkalis, their historical development and gives a simple introduction to their dangers. Worksheet 7Ec(2)

is the Access Sheet.

The second AT presentation link on page 68 opens Acids and

alkalis which provides a list of everyday substances for pupils to classify as acids or alkalis.

Plenaries


Afl


exercise covering the material on page 68. There is also an AT



Afl

The AT document link on page 69 opens a cloze exercise

covering the material on page 69. There is also an AT presentation

version with answers.

3: Quick Check

The Quick Check sheet reinforces some of the key words encountered in this topic and also presents an exercise in logic and deduction.

4: Thinking about alkalis (AT)

OOO: butter, milk, soap. (Possible answers: soap is the only one that is made from fats and ashes; milk is the only liquid.)

PMI: no substances should be alkalis. (Possible answers: P we would not get burnt by alkalis; M acids could not be neutralised;

I how would we get rid of the acids in our mouth when we use toothpaste? How would we treat heartburn?)

PMI: only dilute alkalis should be allowed. (Possible answers:

P the hazards of concentrated alkalis would be removed;

M it would be much more expensive to transport alkalis;

I are some alkalis dangerous for reasons other than being alkalis?)

The fourth AT presentation link on page 68 opens Thinking about

alkalis a PowerPoint presentation version of this task.

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Number and title

Level

Location

Type

Tasks

Acids in action

Must/Should

PB p63

Classwork

Explaining 1

Diamonds are for safety

Must

PB p6465

Classwork

Explaining 2

7E

Quick Quiz

Must/Should

ASP

Classwork

Starter 1

7E

Quick Quiz Answer Sheet

Must/Should

ASP

Classwork

Starter 1

7Ea

Quick Check

Must/Should

ASP

Classwork

Plenary 5

7Ea

Word Sheet

Must/Should

ASP

Homework

7Ea(1)

Diamonds are for safety

Must/Should

CHAP

Access

Explaining 2

7Ea(2)

Spot the hazard 1

Must

CHAP

Practical

Exploring 3

7Ea(3)

Spot the hazard 2

Should

CHAP

Practical

Exploring 3

7Ea(4)

Comparing the hazards

Must

CHAP

Classwork

Explaining 3

7Ea(5)

What hazard?

Must/Should

CHAP

Homework

Plenary 2

7Ea(6)

Cracking the Hazchem code 1

Should

CHAP

Homework

Homework 1

7Ea(7)

Cracking the Hazchem code 2

Could

CHAP

Homework

Homework 2

SS12

Thinking Skills

Must/Should

CHAP

Skills Sheet

Exploring 2, Plenary 1

Code

Framework threads

Year 7

Topic

1.1a1

Scientific thinking: developing explanations using ideas and models

Recognise and explain the values of using models and analogies to clarify explanations.

7Ed

1.1a2

Scientific thinking: challenge and collaboration in the development of explanations

Recognise that scientists of all disciplines and nationalities often work together to develop explanations.

7Ed

1.1a3

Scientific thinking: developing argument

Identify a range of scientific data and other evidence to back an argument and the counterclaim in less complex and/or familiar contexts, e.g. establishing a wind farm.

7Ee

Recognise that scientific evidence can be used to support or disprove theories.

7Ee

1.1b

Applications, implications and cultural understanding

Describe some benefits and drawbacks of scientific developments with which they are familiar.

7Ea, 7Eb, 7Ec

Recognise that decisions about the use and application of science and technology are influenced by society and

individuals.

7Ee

Statement

Topic

a

Research, experiment, discuss and develop arguments.

all

b

Pursue an independent enquiry into an aspect of science of personal interest.

7Ea, 7Eb, 7Ed

c

Use real-life examples as a basis for finding out about science.

all

d

Study science in local, national and global contexts and appreciate the connections between these.

7Ea, 7Ee

e

Experience science outside the school environment including in the workplace, where possible.

7Ea, 7Ec, 7Ee

f

Use creativity and innovation in science, and appreciate their importance in enterprise.

7Ea, 7Ee

h

Explore contemporary and historical scientific developments and how they have been communicated.

7Ec, 7Ed

i

Prepare to specialise in a range of science subjects at Key Stage 4 and consider career opportunities that are provided by science qualifications both within science and in other areas.

7Ea

j

Consider how knowledge and understanding of science informs personal and collective decisions, including those on substance

abuse and sexual health.

7Ea, 7Ed, 7Ee

k

Make links between science and other subjects and areas of the curriculum.

7Eb, 7Ee

Statement

Topic

1a

Use a range of scientific methods and techniques to develop and test ideas and explanations.

all

1b

Assess risk and work safely in the laboratory, field and workplace.

all

1c

Plan and carry out practical and investigative activities, both individually and in groups.

all

2a

Obtain, record and analyse data from

a wide range of primary and secondary

sources, including ICT sources, and use their

findings to provide evidence for scientific

explanations.

all

2b

Evaluate scientific evidence and working methods.

7Ec, 7Ed, 7Ee

3a

Use appropriate methods, including ICT,

to communicate scientific information and

contribute to presentations and discussions

about scientific issues.

7Eb, 7Ec, 7Ee

Pupils materials

Statement

Topic

Sc3 2a

To describe changes that occur when materials are mixed.

all

Objectives

All pupils must:

(1) use universal indicator to test solutions for acidity and alkalinity and to measure pH

(2) give examples of everyday substances that are acids and alkalis.

Correctly use the term pH.

Most pupils should:

(3) explain that, in the past, there were a number of competing theories to explain acidity

(4) describe the main features of the pH scale and classify solutions as strong or weak acids or alkalis

(5) identify the pH of a solution using universal indicator.

Correctly use the words strong, weak (as applied to acids and alkalis), universal indicator.

Some pupils could:

(6) explain that all acids contain hydrogen

(7) use ideas about colour mixing to explain how universal indicators are made, and how they work

(8) describe some alternative theories to explain acidity and explain some evidence for the currently accepted theory.


* This table is repeated in 7Ec.

Topic notes



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What is an acid7Ed

Topic task planner




Finding the balance

Must: pupils follow the instructions on Worksheet 7Ed(3) and

record their results on it.

Should: pupils follow the instructions on Worksheet 7Ed(4).

Could: ask pupils to check the values obtained with universal indicator solution against a pH meter. There are a number of small, solid state meters on the market which do not require

extensive and time-consuming calibration, and give a direct read- out of pH to within 0.1.

Eye protection should be worn. No tasting of any chemicals should be allowed.

Starters

1: Mixing indicators

Ask pupils to name three indicators that they used in Topic 7Ec

(e.g. red cabbage, litmus, phenolphthalein, tea, blackcurrant juice) and what colours they turned in different substances. Pupils

could then discuss what they might expect to happen if you mixed two of the different indicators together.

2: Demonstration: Laboratory indicators

Use this demonstration to introduce pupils to the idea that there

are several laboratory indicators. Set up a row of test tubes in pairs, with a different indicator in each pair. Show what happens when

the indictors are mixed together.


Dropping pipettes; spotting tiles; a variety of common substances (e.g. vinegar, salt, sugar, lemonade, toothpaste, lemon juice, flour, Milk of Magnesia, bleach, washing powder,

scouring powder); universal indicator solution and colour charts;

pH meter; eye protection; Worksheet 7Ed(3) or 7Ed(4).

Must/should: pour a little strong acid (e.g. dilute HCl) into one of

each pair and note the colour change; repeat with alkali (NaOH).

Could: show the colour in acid and ask pupils to predict the alkaline colour given their understanding of colour mixing (e.g. methyl orange is red in acid, so pupils may be able to predict that the alkaline colour has to be yellow to give the orange colour overall).

Eye protection should be worn. Some indicators may be highly flammable, depending on the solvent.

2: pH testing AT

The first AT video link on page 71 opens Testing pHs a virtual version of the pH experiment in Exploring 1, where pupils can test

a number of substances by rolling the cursor over the picture to get the universal indicator colour.

Resources

Rack with boiling tubes; hydrochloric acid (0.1 mol dm-3) (irritant); sodium hydroxide (0.1 mol dm-3); samples of indicators, e.g. methyl orange, thymol blue.

3: Practical: The dilution challenge

Ask pupils to predict what effect making an acid more dilute would have on pH. The predictions could be investigated or demonstrated. Pupils could also be asked if the acid would become more or less corrosive. Alternatively, set this exercise as a challenge show

pupils that the acid is pH 1, and ask them to find out how much water they would need to add to make it pH 2. In theory, the general rule is that a ten-fold dilution causes a shift in pH by

one unit, but the key learning objective here should be accurate planning, experimentation and data analysis, rather than any specific knowledge outcomes.

Eye protection should be worn.

Exploring tasks

1: Practical: Testing the pH of substances

Ask pupils to test substances using universal indicator solution or paper. Make sure that the colour chart the pupils work from

matches the type of indicator being used paper and solution are significantly different in the range of colours and pH values.

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7EdWhat is an acid?

The AT animation link on page 70 opens pH Testing an

interactive activity that asks pupils to guess the pH of various household substances.

Resources

Hydrochloric acid (0.1 mol dm-3); universal indicator solution; pH

meter (if available); test tubes; measuring cylinders.

2: Pupils Book pages 7273 (AB/AT)

This gives pupils the chance to explore the history of ideas about acids, and the conflict between differing theories and scientists. Worksheet 7Ed(2) is the Access Sheet.

4: Thinking about testing pH (AT)

CAP: a bottle labelled universal indicator has a red liquid inside. (Possible answers: an acid has been added to it; the label has been put on the wrong bottle.)

OOO: stomach acid, skin, blood. (Possible answers: skin is not a liquid; blood is slightly alkaline.)

OOO: red, orange, blue. (Possible answers: blue is the only colour that represents an alkali.)

7Ee

The AT document link on page 72 opens Acid observations a

sequence of statements about acids for pupils to correct.

Plenaries

The first AT presentation link on page 71 opens Thinking about

testing pH a PowerPoint presentation version of this task.

1: Quick Check

Ask pupils to produce questions to fit the answers given on the

Quick Check sheet. Pupils can work in small groups before holding

a short class discussion to decide what the questions should be. This can be done orally or in writing.

5: Practical: Make your own universal indicator

This activity could be suitable as an extension activity for those

who have finished other aspects of the work. Although pupils of all abilities may enjoy the challenge, higher-attaining pupils are more likely to be able to appreciate the necessary logic needed to make a sensible prediction.

2: Thinking about uses of acids and alkalis (AT)

PMI: soaps should be more alkaline. (Possible answers: P they would remove dirt more efficiently; M they would be more damaging to the skin and eyes; I how do soaps react with your skin?)

CAP: what might I need to consider when making a new

shampoo? (Possible answers: the pH; its smell; its cleaning power.)

OOO: 1, 8, 14. (Possible answers: 1 is the only pH number that is an acid; 8 is the only number that represents a weak rather than

a strong acid/alkali.)

The third AT presentation link on page 70 opens Thinking about uses of acids and alkalis a PowerPoint presentation version of this task.

Give pupils bottles of a number of indicators and asked them to

produce a mixture which has the maximum number and/or best

range of colour changes. This problem could be approached simply on a trial and error basis, although it is also possible to predict the effect of a suitable mixture using data tables. There is no practical instruction sheet for this activity, but Worksheet 7Ed(8) covers

linked work as an exercise in deduction for a homework activity.

Eye protection should be worn.


Test tubes; dropping pipettes; spotting tiles; set of bottles of different indicators (e.g. litmus, methyl orange, phenolphthalein (highly flammable), thymol blue, bromothymol blue); samples

of solutions at a range of pH values (ideally buffers, but this

is not critical) e.g. hydrochloric acid (pH 1) (corrosive),

ethanoic acid (pH 45) (irritant), water (pH 7) sodium hydrogen carbonate (pH 9), sodium hydroxide (pH 13) (corrosive).


Afl

The AT document link on page 71 opens a cloze exercise,

covering the content of pages 7071. The third AT presentation link

on page 71 opens a presentation version with answers.

Homework tasks

6: Arguments about acids

This activity illustrates some competing theories in the development of ideas about acids.

Should: this is a comprehension task based on Worksheet

7Ed(5). Pupils extract information from the grid to answer the questions. There are some simple calculations on chronology.

Could: the task involves matching and sequencing. Pupils have to read the text on Worksheet 7Ed(6) very carefully to be able to deduce the clues which allow them to assemble the text boxes in

a logical order.

1: Worksheet 7Ed(7) provides instructions for pupils to make a

pH chart to reinforce some of the ideas introduced during the lesson.

Resources

Scissors; glue; magazine pictures illustrating the different substances. Optional: coloured pencils.

2: Worksheet 7Ed(8) shows pupils, in a simple way, how universal

indicators are made, and takes them through a structured series of questions showing how a suitable mixture of indicators can

give rise to a range of colours.

3: Ask pupils to plan an investigation into the relative merits of different soaps, shower gels, etc. against participant bias (blind testing). This is an opportunity for high-attainers to involve themselves in a planning exercise that could give access to

levels 7 and 8. It also deals with the work of scientists in the world of medical research, and the use of blind testing as a technique for eliminating experimenter bias. Worksheet 7Ed(9) will assist pupils in their thinking.

Resources

Could: Scissors; glue.

Explaining tasks

1: Pupils Book pages 7071

(AB/AT)

This introduces ideas about the pH scale, why it was introduced,

how it gets its name, and how we can use universal indicator to measure pH. Worksheet 7Ed(1) is the Access Sheet.

The second AT video link on page 71 opens Environmental

monitoring discussing how both the external and internal environment of a factory is monitored.

The AT document link on page 70 opens pH which provides captions about pH to be completed.

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What is an acid?

7Ed

In the red

7Ec

Tangy tastes

7Eb

Pupils materials

Acids in action

Objectives

All pupils must:

(1) explain that a neutral solution can be obtained by adding an acid to an alkali

(2) recognise that the building of a chemical factory may cause controversy.

Most pupils should:

(3) describe pH changes on neutralisation or dilution of an acid or an alkali

(4) link the strength of acids and alkalis to the potential hazards

(5) describe some applications of neutralisation reactions

(6) be able to state some arguments for and against the building of chemical factories.

Correctly use the word neutralisation.

Some pupils could:

(7) give a balanced evaluation of the arguments for and against the construction of new chemical facilities.


Topic notes



Be prepared: 7Ee

Exploring 1: racks of tubes may need to be prepared in advance.

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7EeFinding the balance

Topic task planner




7Ea

Starters

Exploring tasks

1: Thinking about acids and alkalis (AT)

1: Practical: Rainbow fizz

This practical reinforces ideas about the pH scale, and also develops pupils ability in observation and following instructions. There is

a real sense of achievement if this experiment works well, but it does need a degree of care. Over-enthusiastic mixing will mean that pupils lose their rainbows. You are advised to check this experiment out first. It is advisable to prepare tubes before the lesson.

Afl

Carry out a Thinking skills exercise to remind pupils of what

they have learned so far about acids and alkalis.

OOO: sulphuric acid, citric acid, ascorbic acid. (Possible answer: sulphuric acid is the only one not present in fruits like lemons and limes.)

OOO: red, blue, yellow. (Possible answers: yellow is not a colour of litmus; blue is the colour of universal indicator with alkalis; the

other two are acid colours.)

OOO: vinegar, sugar, soap. (Possible answers: vinegar is the only acid/liquid; soap is the only alkali.)

OOO: hydrogen, oxygen, sulphur. (Possible answers: hydrogen is the only one thats in every acid; sulphur is the only solid; sulphur

is not in water.)

Must: pupils can record their work using the framework provided

in Worksheet 7Ee(3).

Should: pupils design their own format for recording results.

Make sure that pupils have been shown how to smell chemicals safely. Eye protection should be worn.

Note that there is usually more than one possibility for the odd one

out, and the important outcome is the pupils justification of his/her decision. Give pupils one point for a correct scientific reason, and bonus points if they can think of a reason that no-one else has thought of.

The first AT presentation link on page 76 opens Thinking about acids and alkalis a PowerPoint presentation version of this task.


Eye protection; test tube rack; boiling tube containing about

1 g anhydrous sodium carbonate (irritant); tube 1 test tube containing about 2 cm3 water; tube 2 test tube containing

about 10 drops universal indicator; tube 3 test tube containing about 2 cm3 approx. 0.5 mol dm-3 ethanoic acid; tube 4 test

tube containing about 2 cm3 approx. 0.5 mol dm-3 ethanoic acid; Worksheets 7Ee(2) and 7Ee(3).

2: Mixing solutions

Ask pupils to speculate on what the outcome might be if solutions

of given pH values were mixed. You could do this as a brief introductory demonstration, or use it as a discussion exercise.

Pupils may also identify volume as a key variable.

2: Planning a neutralisation investigation

Worksheet 7Ee(5) asks pupils to evaluate critically a number of

plans for a neutralisation investigation. This can be used as a stand- alone activity, or in conjunction with the investigation in Exploring 4.

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Finding the balance7Ee

3: Titration AT

The AT animation link on page 74 opens Neutralise an acid by titration this animation allows pupils to undertake a virtual neutralisation in which they can add an alkali to an acid and watch the change in pH that takes place.

Plenaries

1: Concept map

Ask pupils to draw a concept map linking all the ideas they have encounte

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