acids and metals

Acids and MetalsLevel E

Level E Science Topic Book

Earth and Space

Acids andMetals

Glasgow City Council

Designed and Published byEducation Services

Education Improvement ServiceWheatley House

25 Cochrane StreetGlasgow G1 1HL

Phone 0141 287 2000

ACIDS AND METALS Level E: Science Topic Book

Glasgow 5-14 Science Programme Education Improvement Service 2

Acids and MetalsContents

List of Learning Outcomes

Topic Outline

Activity Support Sheets

Teachers Science Notes

Investigations

Topic Assessment Sheets

Homework Sheets

Glossary

Pupil Checklist

Resources and Safety Issues



Acids and MetalsLearning Outcomes

TOPIC: Acids and Metals Level E Stage S1/S2

Knowledge and Understanding Strands Changing Materials.

Learning Outcomes:By the end of the unit the pupils should be able to: Level

Measure the pH of common solutions. E

Identify acids, alkalis and neutral solutions from the pH values. E

State that the lower the pH of an acid the greater the acidity; the higher the E

pH of an alkali the greater the alkalinity.

State that acids and alkalis combine to form a neutral solution. E

State that when an acid neutralises an alkali, a salt and water is formed. E

Give real life examples of neutralisation. E

Plan and carry out a practical investigation on the differences in E

acid content in a range of soft drinks.

List metals in order of reactivity with oxygen, water and acid. E

Give examples of how reactivity relates to uses and sources of metals. E

State that more reactive metals can displace less reactive metals from their solutions. E

State that electrolysis can be used to obtain a metal from a solution. E

Describe the effects of electroplating. E

Give examples of how some metals are extracted. E



The following topic outline suggests activities and examples of ongoing assessments to take forward the Learning

Outcomes listed for this study. To suit their own classes and situations, teachers may want to add to, or adapt some of

these. The main aim, however, is to ensure that children are given the opportunity to overtake the learning outcomes

listed.

Acids and MetalsTopic Outline

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LearningOutcomes

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Level Learning Activities Resources Assessment

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ACIDS AND METALS Level E: Topic Outline


Ask pupils what they already knowabout acids (many will mentionburning, corrosion, acid rain,vinegar, citric acid, sour sweets,rotting teeth, etc.). Develop theneed for a way to identify an acid(and later measure the degree ofacidity).Mention the pH scale consisting ofnumbers 0 to 14 which do this. Atthis point you could demonstratesome solutions and their pH using apH meter/probe with interface.Introduce the concept of anindicator and demonstrate the useof Universal Indicator as a way ofindicating the pH of a solution. Nowget pupils to measure the pH of avariety of (safe) common solutionswith Universal Indicator paper (orthe pH meter/probe).

Get pupils to use the values of pHmeasured from Support Sheet 1 tocomplete a table which sorts thesolutions into acids, alkalis andneutral solution.

The above activities will lead toopportunities to discuss what ishappening the further away frompH 7 you go. Teachers should, ifthey have not already done so,introduce the terms acidity/acidicand alkalinity/alkaline as well asacids and alkalis. Get pupils toname some strong acids andalkalis.

Measure the pH ofcommonsolutions.

Identify acids,alkalis andneutral solutionsfrom the pHvalues.

State that thelower the pH of anacid the greaterthe acidity; thehigher the pH ofan alkali thegreater thealkalinity.

Pupils can identify the pH(values, 0 - 14) of asolution from the colour ofpH paper or using a probeor Universal indicatorsolution.

Pupils can state that acidshave a pH value < 7,neutral solutions have apH value = 7, alkalis have apH value > 7.

Pupils can rank substancesin order of acidity/alkalinity using pH values.

Universal Indicator paperwith colour chart, pH meteror probe with interface,variety of commonsolutions e.g. lemon, lime,orange and grapefruitjuices, vinegar, citric acid,cream of tartar, coffee, tea,de-ionised water, saltsolution, Epsom salts, milk,milk of magnesia, washingup liquid, bicarbonate ofsoda, weak ammoniasolution, etc., beakers,safety glasses. (Possiblydroppers and dimple tiles.)

Activity Support Sheet 1.



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State that acidsand alkaliscombine to form aneutral solution.

State that when anacid neutralises analkali a salt andwater is formed.

Give real lifeexamples ofneutralisation.

Use 10ml syringes (use red andblue tape to identify which syringewill be used for the acid and alkali)to draw 10ml of alkali and put into abeaker (50ml) to which Universalindicator has been added. Nowadd acid (using the red-tapedsyringe) drop by drop, stirringconstantly noting the pH asindicated by the colour change (orpH probe). When the pH reaches 7,point out to pupils the volume ofacid added is the same as the initialvolume of alkali.

Repeat the experiment with alkalibeing added to acid. Point out thatneutralising an acid moves its pHup towards 7 and neutralising analkali moves its pH down towards 7.Use a pH meter or probe withinterface to graph volume versuspH for acid to alkali or alkali to acid.

Pupils can then repeat the aboveexperiment without using indicatorand then evaporate off the water toobtain the salt. (Before evaporation,pupils can check the pH using pHpaper.)

Other examples could be sodiumhydroxide and ethanoic acid,sulphuric acid and ammoniasolution.

Get pupils to find out about theapplications of acid, alkalis andneutralisation using the Find outabout sheet.

Some pupils can researchneutralisation examples such asmilk of magnesia for indigestion,treatment of garden soil, sodiumbicarbonate for acid bee stings andvinegar for alkali wasp stings.Others can research uses of acidsand alkalis such as skin hair care,fruit juices and vinegar andcleaning products. Others still mayresearch the harmful, irritant andcorrosive nature of acids andalkalis and precautions needed.

Syringes (10ml) of HCl andNaOH (same molarity e.g.0.1 M) Beakers, universalindicator, safety glasses.



Syringes (10ml) of HCl andNaOH (e.g. 0.1 M.)Beakers, safety glasses pHpaper evaporating basins,Bunsen burners, tripodstands.


Books, Internet access, CDROMs.


Pupils can state thatadding acid to alkalilowers the pH and addingalkali to acid raises the pHuntil pH 7 is reached whenthe solution is neutral.

Pupils can state that theneutral solution formed isa salt and water.

Pupils can identify someacids, e.g. vinegar, lemonjuice.

Pupils can identify someeveryday uses of acids,e.g. in foods, medicines,cleaning materialstreatment of bee/waspstings, treatment of soil,etc.

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Give real lifeexamples ofneutralisation,contd.

Plan and carry outa practicalinvestigation onthe differences inacid content in arange of softdrinks.

After their research you can getpupils to try out one or twoexamples as experiments. Get themto plan and record what they do.For example treatment forindigestion; pupils take 20 ml of HCland add to beaker, add someuniversal indicator, then addindigestion powder or indigestiontablets to beaker stir and watchwhat happens to pH. Ask pupilswhat type of reaction is taking placeand which type of chemical must bepresent in the indigestion powder.

Treatment of garden soil (farmland).Mention acid rain and its effect onraising soil acidity which can affectplant growth. Repeat the activityabove but replacing indigestionpowder with lime.

Give pupils a variety of soft drinksto test. Pupils can use pH paper orbetter still a pH meter or probe withinterface.

Use 0.1 M HCl, stirring rods,beakers, selection ofindigestion tablets/powders, universalindicator.


As above, but replaceindigestion powder withlime.


Various soft drinks eachwith a different acid contentare required, universalindicator, pH paper, pHmeter, beakers, measuringcylinders, syringes.

I am a Scientist

investigation sheets.

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List metals inorder of reactivitywith oxygen,water and acid.

Give examples ofhow reactivityrelates to usesand sources ofmetals.

Burn samples of magnesium andcopper to demonstrate theirreaction with oxygen and toillustrate either end of the reactivityseries. Pupils can look at display ofmetals that have been left exposedto oxygen for a month and compareit with fresh samples (arrange thedegree of corrosion to reinforce thereactivity of the metals).

Teacher demonstration of metals inwater using small samples ofpotassium, sodium (caesium can beshown using a video). Pupilsshould then try out samples ofcalcium, magnesium, aluminium,zinc, iron, tin, copper (note theorder).

Get pupils to repeat theirexperiments using dilute HCLinstead of water (Ca is veryreactive!). If any pupil (or teacher)has a piece of gold they are willingto add to acid that can be tested aswell. Include lead in the metalsamples to be tested.Pupils can test a sample of the gaswhich is generated to identify it ashydrogen. (The test for hydrogen iscovered in the Unit ChemicalReactions.) Pupils find it interestingto see that there is hydrogen gasgiven off by the action of a metal.

Discuss the experiments withpupils and then complete thereactivity series table. Point out thatmetals near the top react withoxygen and water; metals near themiddle react with acid but notwater and metals near the bottomdo not react at all.

Get pupils to research everydayuses of metals (and dates ofdiscovery) and how this relates totheir reactivity and use. Pupils canalso find out where different metalscome from. Pupils can write reportindividually or in a group andpresent work/or display work tothe rest of the class.

Safety screen, Bunsenburner, mat, tongs,magnesium ribbon, copperfoil; samples of metals,fresh and partially corroded e.g. Mg, Zn, Fe, Sn, Cu, Ag,Au.Activity Support Sheet 7.

Safety screen, trough withwater, samples of, K, Na, Ca,Mg, Al, Zn, Fe, Sn, Cu, Pb, testtubes and racks, safetygoggles.Activity Support Sheet 8.

Dilute HCl, CD-ROMs, MultiMedia Science School hasvideo clips of the group onemetals, also CrocodileChemistry will allow you toshow animations of theexperiments.Activity Support Sheet 9.


Books, Internet access, CDROMs.Activity Support Sheet 11.

Pupils should be able to listmetals in the correct orderof reactivity: potassium,sodium, calcium,magnesium, aluminium,zinc, iron, tin and copper.

Pupils can give examplesthat show how reactivity ofa metal is related to its use.

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State that morereactive metalscan displace lessreactive metalsfrom theirsolutions.

State thatelectrolysis can beused to obtain ametal from asolution.

Describe theeffects ofelectroplating.

Give examples ofhow some metalsare extracted.

Get pupils to use metals to displaceless reactive metals from theirsolutions. Give them a solution of aless reactive metal and a morereactive metal in metallic form toinsert.The inserted metal disappears andthe metal originally in solution isdeposited. For example - zinc metalinto a solution of copper sulphate.Iron metal into a solution of coppersulphate. Magnesium metal into asolution of nickel sulphate.Point out that the new metal hasbeen formed and that the originalmetal that was placed in solution isnot present any longer. Highlightany change in colour of the originalsolutions and possible change intemperature.

Let pupils carry out the electrolysisof copper (II) chloride and observeand record the formation ofproducts at the electrodes particularly the deposition ofcopper.Demonstrate the electrolysis ofmolten lead bromide. Show a videoclip for this experiment.

Safety Note: Use low voltage incopper chloride experiment toprevent build up of chlorine gas;

ventilate room while carrying outexperiment.

Get pupils to carry outelectroplating of a steel nail withnickel or with copper. Point out thatit is possible to electroplate onemetal with another usingelectrolysis.Discuss with pupils how thismethod is used to protect metalsfrom corrosion.

Get pupils to research theextraction of metals from their orese.g. Iron, aluminium, copper, lead,gold, silver.

Zinc, iron and magnesiummetals. Copper sulphatesolution and nickelsulphate solution.Or any other suitablecombinations.Small beakers, stirring rods,(or boiling tubes) safetygoggles.


Solution of copper (II)chloride, carbon electrodes,power pack, leads, beakers,safety goggles.

Lead bromide and suitableapparatus for carrying outthe electrolysis experiment.


Solutions of copperchloride and nickelsulphate, power pack,leads, carbon electrodes,steel nails, beakers,crocodile clip.


Books, Internet access, CDROMs.Activity Support Sheet 15.

Pupils can state that metalshigher in the reactivityseries can displace metalslower in the series fromtheir solutions.

Pupils state thatelectrolysis is a method ofextracting metals fromsolutions.

Pupils can describe theeffects of electroplatingone metal with anotherusing electrolysis.

Pupils can explain theextraction of some metalsfrom their ores.

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Acids and MetalsActivity Support Sheets

Primarily the pupil worksheets support children through practical activities or experiments. A few reinforce knowledge

and understanding.

The Glasgow 5-14 Science Programme promotes an enquiry-based approach to learning which is characterised by first-

hand experience. Great care has been taken, therefore, not to place an over-reliance on worksheets.

ACIDS AND METALS: Level E: Activity Support Sheet

Name


1

Measuring pHUse the table here to record your values for the pH of the solutions youtested. Write the name of your solution in the left hand column the firsttwo have been done for you.

Acid, alkali or neutral

Use the values of pH to decide if the solution is an acid, alkali or neutral and write your result in thelast column.

solution

Hydrochloric acid

Sodium hydroxide

pH acid or alkali or neutral


Name


2

Adding acid to alkaliAdd the alkali to the beaker first and use the table to record how the pHchanges as you add acid.

Use the words in the word bank to complete the sentence about adding acid to alkali.

When acid is added to , the pH of the mixture

until the solution is

Wordbank

neutral decreases alkali

Volume of alkali 10 ml

2

4

6

8

10

volume of acid added (ml) pH

acid alkali

universal indicator


Name


3

Adding alkali to acidAdd the acid to the beaker first and use the table to record how the pHchanges as you add alkali.

Use the words in the word bank to complete the sentence about adding acid to alkali.

When alkali is added to , the pH of the mixture

until the solution is

Wordbank

neutral increases acid

Volume of acid 10 ml

2

4

6

8

10

volume of alkali added (ml) pH

acid alkali

universal indicator


Name


4

Making salt

acid alkali

acid + alkali a salt + water

Space for diagram

Describe how hydrochloric acid and sodiumhydroxide can be used to make common salt(sodium chloride).


Name


5

Finding out about neutralisationThis sheet will help you to plan how you are going to carry out your research, record your findings andpresent a report to your class.

1. Where are you going to find the information you need?Write the names of the books, CD ROMs or web sites you use in this box.Your teacher may be able to help you with this.

2. What information are you going to need?Use this box to write down any questions you want to find the answers to, e.g.How is indigestion cured? How are bee and wasp stings treated?How do gardeners treat soil?

3. Now write down all of the information you have found.Do this in your jotter or on a separate piece of paper.

4. How are you going to present your findings?You could use a poster, a written report, or a report you read out to your class.Be creative what about a poem, a play or a presentation?


Name


Trying it outCollect some dilute hydrochloric acid in a test tube and add a few dropsof Universal Indicator.Crush an indigestion tablet. Add the crushed tablet bit by bit to the acid(stirring all the time) until the acid is neutralised.Use the space below to plan out your experiment.

6

Treating the soil

Collect a small amount of soil, add some water and a few drops of Universal Indicator solution.Change the pH of the soil to make it alkaline good for roses!Use the space below to plan out your experiment.


Name


7

Reactions of metals with oxygenCompare the appearance of each fresh metal sample with how it looksafter being exposed to oxygen for a month.Describe the differences as accurately as you can.

The most reactive metal is the most corroded.Place the metals below in order of how reactive they are.

less reactive more reactive

magnesium iron tin

gold zinc copper

name of metal fresh after a month's exposure


Name


8

Reactions of metals with waterDescribe how each metal reacts with water as accurately as you can.

name of metal decription of reaction with water

Place the metals below in order of how reactive they are in water.


magnesium iron caesium

potassium sodium zinc calcium


Name


9

Reactions of metals with acidDescribe how each metal reacts with acid as accurately as you can.

Place the metals below in order of how reactive they are in acid.


magnesium iron tin

copper aluminium zinc lead

name of metal decription of reaction with acid


Name


10

Reactivity SeriesComplete the table below using the following metals:aluminium, zinc, potassium, sodium, clacium,magnesium, gold, slver, iron, tin, lead. copper, caesium.

react with water metal react with acid


Name


11

Finding out about metalsThis sheet will help you to plan how you are going to carry out your research, record your findings andpresent a report to your class.


2. What information are you going to need?Use this box to write down any questions you want to find the answers to, e.g.Why is copper used for household plumbing? Whats so special about gold?


4. How are you going to present your findings?You could use a poster, a written report, or a report you read out to your class.Be creative what about a poem, a play or a presentation?


Name


12

Using reactivity displacementSet up the two experiments shown here.In the space below each diagram, record any changes you see asaccurately as possible.

zinc sulphate solution

copper zinc

copper sulphate solution


Name


at the positive electrode at the negative electrode

13

Splitting upUse this sheet to record your observations of the electrolysisof copper chloride.

+

positive electrode negative electrode

250 ml beaker

Power PackDC Supply

copper chloride


Name


14

ElectroplatingUse this sheet to record your observations of electroplatinga steel nail with copper.

+

positive electrode steel nail

Power PackDC Supply

copper sulphate


Name


15

Finding out about metal extractionThis sheet will help you to plan how you are going to carry out your research, recordyour findings and present a report to your class.


2. What information are you going to need?Use this box to write down any questions you want to find the answers to, e.g.What is an ore? What happens to it in a blast furnace?


4. How are you going to present your findings?You could use a poster, a written report, or a report you read out to your class.Be creative what about a poem, play or presentation?

ACIDS AND METALS Level E: Teachers Science Notes


Acids and MetalsTeachers Science Notes

Many teachers do not feel confident to teach science outwith their own specialist area. They are concerned that their own

limited knowledge restricts what they should be teaching. The materials in this programme are designed to help increase

teacher confidence.

These notes provide a summary of the science ideas covered in this topic and relate directly to the suggested learning

activities.



Acids and MetalsTeachers Science Notes

AcidsPupils often describe acids as being dangerous and able to dissolve things like the blood from the creature in Alien. You

can have a good session exploring the misconceptions.

Acids are really compounds which generate hydrogen ions when dissolved in water. The degree of acidity is measured by

the hydrogen ion concentration called the pH scale.

Acids and alkalisYou can describe acids as substances which like to give hydrogen. The opposite of an acid is a base a substance which

likes to accept hydrogen. In this unit, we only mention alkalis - which are bases that are soluble in water. Neutral substances

do not like to give or accept hydrogen. A solution is acidic, alkaline or neutral.

pH = 4

pH = 5

pH = 6

pH = 7

pH = 8

pH = 9

pH = 10

pH ScaleA good way to help pupils remember what they are measuring is to call the

pH scale the Power of Hydrogen scale. Values of pH less than 7 indicate the

solution is an acid; a value greater than 7 indicates the solution is an alkali; a

value equal to 7 indicates a neutral solution. (All substances tested in this

unit will be in solution.) A strong acid will have a pH value of 0 and a strong

alkali will have a pH value of 14.

The pH number of a solution can be determined by colour matching using

Universal Indicator which comes as a liquid or in strips of paper which has

been impregnated with Universal Indicator called Universal Indicator

Paper or, more normally, pH paper.

NeutralisationAcids and alkalis can cancel each other out in a process called neutralisation. This has many useful applications which

include:

Treating bee stings (venom is acidic) with sodium bicarbonate and wasp (venom is alkaline) stings with vinegar.

Indigestion tablets (alkaline) to cure acid indigestion e.g. milk of magnesia.

Lime (alkali) used by farmers to raise soil pH.

All neutralisation processes move the pH of an acid or alkali towards 7. The products of all neutralisation reactions include

a salt and water. (With a carbonate the gas carbon dioxide is also formed.) To name the salt, use the metal from the alkali

for the first part and the name of the acid for the second part, e.g. reacting sodium hydroxide and Hydrochloric Acid

together would give you sodium chloride. Testing the pH of salts will show that not all salts are neutral.

Sample of colours of UniversalIndicator showing pH values 4-10.



METALS REACTION WITHOXYGENREACTION WITH

WATERREACTION WITH

ACIDREACTION WITHCOMPOUND

Potassium

Sodium

Lithium

Calcium

Magnesium

Aluminium

Zinc

Iron

Nickel

Tin

Lead

Copper

Silver

Mercury

Gold NO

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Reactivity SeriesThe reactivity series is a list which places metals in order of their readiness to take part in chemical reactions. Metals at the

top react faster with water and dilute acid and burn more vigorously in oxygen. See the table below for the reactivity of

common metals.

Metals higher up the table can also push out lower ones from compounds. This is called displacement.

When a metal higher up the reactivity series is added to a solution containing a metal lower in the series, the lower metal

is forced out of the solution and is deposited the higher up metal replaces it in solution.



The reactivity series affects how metals are used. Metals like

lead and copper are used for roofs and piping because they

do not react easily.

Iron is common and is used to make many things, but it has

to be protected from corrosion (electroplating).

Very unreactive metals like gold and silver are used for

jewellery because they stay shiny.

Electroplating of MetalsElectroplating is the coating of an object (which must be a conductor) with a metal. The object to be coated is attached to

the negative electrode. The positive electrode would be the coating metal (otherwise the coating metal comes out of solution).

These would then be placed in a solution of the coating metal. An electric current passes through the solution due to the

movement of electrons and ions in the solution. This is also the basis of the operation of a battery.

The Glasgow Science Centre has a titanium roof.



METAL EXTRACTED ORE USE

copper chalcopyriteElectrical wiring good conductor

of electricity

aluminium bauxiteCans; aircraft bodies

because of its lowdensity

zinc smithsoniteUsed to protect iron

by galvanising

magnesium magnesium chlorideFireworks; flares;

medicines

tin cassiteriteSolder; anodising

steel

iron haematite

Iron is used to makesteel girders and steel to

reinforce concretebecause it is strong

under tension

Extraction of MetalsElectrolysis is a method of extraction using electricity to split up a metal ore. This method of extraction is only used to

extract the metals from the top of the reactivity series. The metal always forms around the negative electrode during

electrolysis (because metal ions are positive).

Less reactive metals are extracted using heat and carbon (coke) usually in a furnace. The extraction of iron is carried out in

a blast furnace using this method. The very unreactive metals such as gold and silver have been known since earliest

civilisation and are often found in their metallic state.

ACIDS AND METALS Level E: Investigations


Acids and MetalsInvestigations

Although investigating is an activity that crosses the curriculum, it has special significance for

science. First-hand investigations are central to the way in which young children learn science,

providing opportunities to plan fair tests, make observations, hypothesise, predict, collect

evidence, research, survey and discuss. Through such means, opportunities arise to infer,

deduce, calculate, draw conclusions from evidence, make judgements and debate important

issues. Characteristics such as curiosity, responsibility, perseverance, cooperation, attention

to detail and divergent thinking are also encouraged.

Environmental Studies 5-14 National Guidelines (2000)

Open-ended investigations are proven to increase pupil motivation, thinking skills and knowledge and understanding.

The investigative skills of planning, fair testing, observing, measuring, recording, reporting and evaluating are best promoted

through investigative work and to this end, this topic includes a topic investigation.



By the time pupils reach S1/S2, they will have, with the support of their teachers, developed a range of investigative skills.

If the Glasgow Science Programme has been used throughout the primary stages, almost all pupils will have achieved skills

at level C by P7 and most will be working at level D. During S1/S2, therefore, pupils should concentrate on the skills at D to

F. The teacher will decide which level is most appropriate for each pupil. The progression in S1/S2 from Level D to Level F

is reflected in the difficulty of the planning and recording sheet for the topic. However, to ensure differentiation, the I am a

Scientist sheets from topics at other levels can be used.

This section of the booklet offers teachers advice on developing the skill areas of

Preparing for tasks

Planning

Predicting

Fair testing

Carrying out tasks

Observing and measuring

Recording

Reviewing and reporting on tasks

Reporting and presenting

Interpreting and evaluating

It also suggests a topic investigation that will promote scientific enquiry.

It is important that when carrying out investigations pupils are encouraged to suggest ways of answering the investigating

question.

The accompanying Investigation Planning and Recording Sheet I am a Scientist takes pupils through a structure for

investigation and allows them to systematically record their findings. A separate sheet is included for each skill strand.



Preparing for TasksPreparing for tasks includes understanding a task and planning a practical activity, making predictions and

undertaking fair testing.

By the time pupils reach S1, they will have been working at level D and should be able, with help from the teacher,

to contribute to the whole investigative process from planning to evaluation. Teachers in secondary schools

should be aware that the 5-14 programme is not an end point but a pathway to Standard Grade courses in S3/S4

and skills development should lead naturally to pupils acquiring those skills required for Standard Grade

investigations. Even so, pupils at the beginning of S1 will require more support than those at the end of S2.

The following outlines the progression in skills for preparing for tasks for levels D to F and includes the

investigative skill objectives from Standard Grade (all sciences).

Level DPupils are able to:

identify two or three questions to investigate

provide reasons for planning decisions

include fair testing in planning by changing one

factor

show awareness of the significance of variables

Level EPupils are able to:

identify a number of questions to investigate

plan a valid and reliable test for a given hypothesis

Level FPupils are able to:

formulate a testable hypothesis

plan an appropriate strategy to investigate a

hypothesis

Standard GradePupils are able to:

demonstrate understanding of the problem posed (G1)

state the aim of the investigation (G2)

articulate a testable hypothesis (G3)

suggest a broad strategy to adopt (G4)



Carrying out TasksCarrying out tasks includes observing, measuring and recording findings.

By the time pupils reach S1, they will have been working at level D and should be able, with help from the teacher,

to contribute to the whole investigative process from planning to evaluation. Teachers in secondary schools should

be aware that the 5-14 programme is not an end point but a pathway to Standard Grade courses in S3/S4 and

skills development should lead naturally to pupils acquiring those skills required for Standard Grade investigations.

Even so, pupils at the beginning of S1 will require more support than those at the end of S2 although their repertoire

of measurement skills should be quite well developed on entry to secondary.

The following outlines the progression in skills for carrying out tasks for levels D to F and includes the investigative

skill objectives from Standard Grade (all sciences).


make an appropriate series of accurate

measurements

select an appropriate way of recording findings


select and use appropriate forms of graphical

presentation


make a series of measurements of the input and

outcome variables

make their own selection and be able to use

appropriate recording and presentation


adopt appropriate and safe procedures (E1)

identify the input variable to be used and alter it

over a suitable range (E2)

control all relevant variables as necessary (E3)

make valid, reliable measurement of the outcome

variable (E4)



Reviewing & Reporting on TasksReviewing and reporting on tasks includes reporting and presenting as well as interpreting and evaluating results

and processes.

Scientific investigations lend themselves to reporting and presenting information to fellow pupils. This forces

children to clarify their thinking and knowledge. Explaining to others is at the heart of constructivism and is a very

powerful way to learn developing metacognition in pupils.

The following outlines the progression in skills for reviewing and reporting on tasks for levels D to F and includes

the investigative skill objectives from Standard Grade (all sciences).


make an organised report of an investigation using

appropriate illustrations

provide explanations related to scientific

knowledge

draw conclusions consistent with the findings

identify limitations of the approach used.


write a structured report of an investigation using

appropriate illustrations and vocabulary

establish links between the results and the original

hypothesis

suggest improvements to the approach used


evaluate a range of aspects of the investigation


tabulate results with appropriate headings and units

of measurement (RR1)

present the results on a graph or chart (RR2)

draw a valid conclusion inter-relating the appropriate

variables (Ev1)

use results to evaluate the original hypothesis (Ev2)

describe how the investigation was carried out (RR3)



Acids and MetalsTopic Investigation: Teacher InformationWhich drink is the most acidic?

Preparing for tasksWhat will be measured? The pH (the acidity) of the drink, type (name ) of drink.

How will it be measured? Using pH paper or universal indicator or because of the colour of some of the

soft drinks a pH meter may be more suitable.

What needs to be kept the same? The volume of soft drink.

Make a hypothesis. There is no obvious trend to determine. Pupils may wish to take the

investigation further by looking at label contents or compare still and fizzy

drinks.

Carrying out tasksHow will measurements be recorded? Use a table headings could be:

Name of soft drink and pH value

Reviewing and reporting on tasksMake a graph A bar graph in this case.

Draw a conclusion Which drink gave the highest/lowest pH?

Was the prediction correct?

Can you explain? Drinks with acid give a low pH. Milk is alkaline, although if it is left out for a few

days its pH decreases. This is a possible alternative investigation.

Write a report. Include a plan, diagram of apparatus , table of measurements , and description

of procedure.

If another pupil could repeat the investigation from the report, it is good.



a science investigation report

by:

Preparing the taskTitle

(Investigative question)

What Iwill change

(Input variable)

What will bemeasured?(Outcome variable)

How will it bemeasured?

(Description of apparatus)

What do I thinkwill happen?

(Hypothesis)

What I will do tokeep the test

fair?(Control of variables)



Carrying Out the TaskMy table of results

A graph of my results

Comments (e.g. relationships between variables)



Reviewing & Reporting on the TaskDiagram of my apparatus

Description of what I did:

Summary of what I found out (Conclusion/links to hypothesis):

Description of improvements (Evaluate at least two aspects):

Acids and Metals

ACIDS AND METALS Level E: Assessment Sheets

Assessment Sheets

The topic outline offers suggestions for ongoing assessment. The following sheets are provided to aid summative assessment

of pupils knowledge and understanding. They can be copied and used during the topic or at the end of the topic if the

teacher prefers.

The pupil evaluation sheets ask pupils to think about how much they have learned and what areas they enjoyed. These

sheets give the pupils an opportunity to give feedback to the teacher and provide some evidence for the teacher on the

pupils developing attitudes.




Evaluation Sheet

I have completed a topic about:

These are the things I have learned and can do better:

Next time I do science I want to get better at:

Shade in the box to show how much you enjoyed the Topic.

Comment:

very poor very good

ACIDS AND METALS: Level E: Assessment Sheets

Name

Use this page to record things you want to get off your chest!

Some dentists would like to see fizzy drinks banned because they damage teeth. Others wantthe acid content reduced or the drinks to cost more. The makers dont want the drinks banned.They are also worried that changing the acid content will affect the taste. What do you think?

Find out some information about the acid content in drinks. Revise what you know about teeth andtooth decay.

Give your opinion on the issue below.


ACIDS AND METALS: Level E: Assessment Sheet

Name


1

What colour is pH paper when in an acid?

What colour is pH paper when in an alkali?

What colour is pH paper when in neutral substances?

Name two common solutions which are acidic.

Name two common solutions which are alkali.

Name two laboratory acids.

Name two laboratory alkalis.

KU


Name


2KU

In an experiment, Caitlin was asked toorganise some solutions into threegroups:

What name could be given to a solution in:

Group A?

Group B?

Group C?

What chemical could Caitlin use to test the pH of liquids?

What happens to the pH of an acid as it is neutralised?

What happens to the pH of an alkali as it is neutralised?

A

B

C

less than 7

7

more than 7

GROUP pH

pH 1

pH 2

pH 3

pH 4

pH 5

pH 6

pH 7

pH 8

pH 9

pH 10

pH 11

pH 12

pH 13

pH 14


Name


3KU

Taking indigestion remedies to cure acid indigestion is an example of neutralisation.What two things are always made when neutralisation takes place?

+

Describe another example of neutralisation.

Rearrange the following metals in order of reactivity; putting the most reactive on top.

zinc

copper

calcium

tin

sodium

aluminium

potassium

magnesium

iron

METAL ORDER


Name


4KU

Gold and silver have been used to make jewellerysince the earliest times.Other metals such as calcium and aluminium wereunknown until approximately 200 years ago.

Explain why gold and silver were among the first metals to be discovered.

Explain why calcium and aluminium were not discovered until recent times.

Some metals were added to solutions as shown below. In the box provided state which metal is leftafter the reaction takes place.

iron + copper sulphate

tin + zinc sulphate

magnesium + nickel chloride

METAL FORMED


Name


5KU

Describe what happens when copperchloride is electrolysed.Remember to describe what happens at theelectrodes.

Space for diagram

Screws, which are to be used outside, are often electroplated with zinc.Describe how a steel screw can be electroplated.

Why is it useful to use zinc-plated screws outdoors?


Name


6KU

Describe two different extraction processesfor any metals you have studied in thistopic.Method 1:

Space for diagram

Space for diagram

Method 2:


Name


7PS

Jeff added dilute potassium hydroxide slowly to dilute sulphuric acid. After he added each drop, hetested the pH of the solution and recorded the results in a table.

Draw a line graph of Jeffs results.

How many drops of potassium hydroxide neutralised the acid?

0

2

4

6

8

10

12

2

3

4

5

6

7

8

NUMBER OF DROPS pH OF SOLUTION


Name


8PS

Name the acid and alkali which could be used to prepare solutions of each of the following salts.

Experiments were set up to investigate the rate of reaction of six metals, A, B, C, D, E and F with dilutehydrochloric acid, oxygen and water. The results are shown below.

Place the six metals in order of reactivity. (Start with the least reactive.)

magnesium sulphate

sodium chloride

calcium nitrate


A

B

C

D

E

F

no reaction

vigorous reaction

slow reaction

explosive reaction

slow reaction

vigorous reaction

no reaction

slow reaction

slow reaction

vigorous reaction

no reaction

fast reaction

no reaction

slow reaction

no reaction

very quick reaction

no reaction

quick reaction

METAL REACTION WITH ACID REACTION WITH WATER REACTION WITH OXYGEN

Acids and Metals

ACIDS AND METALS Level E/F: Homework Sheets

Homework Sheets

Improving Science Education 5-14 (1999), section 2.3 makes the following statement about homework:

Science homework was rarely given in primary schools and was not sufficiently purposeful or challenging in

secondary schools.

The following homework sheets are designed to address this need. The questions are intended to offer the opportunity for

pupils to think, write extended answers and try some simple practical tasks. Teachers should ensure that pupils are given

any necessary safety advice in relation to the practical tasks (e.g. do not drink the water after adding salt, if the tumbler

breaks, ask an adult to help clean the broken glass).

Although entitled Homework Sheets, these questions can be used to check pupils understanding and can be used in

class as well as at home. The material supplied here is not exhaustive. Teachers can and should use other sources for

homework in the course of their teaching.


ACIDS AND METALS: Level E: Homework Sheet

Name


1

The table below was copied from Universal Indicator paper (pH paper).

1pH 2 3 4 5 6 7 8 9 10 11 12 13 14

red

pink

oran

ge

beig

e

yello

w

lime

gree

n

gree

nne

utra

l

slig

htly

aci

d

very

aci

d

slih

tly a

lkal

ine

very

alk

alin

e

dark

gre

en

turq

uois

e

pale

blu

e

blue

dark

blu

e

viol

et

purp

le

Describe how the pH of a solution can be measured using pH paper.

What colours does pH paper turn in acids?

What range of pH values indicates a solution is acidic?

What range of pH values indicates a solution is alkaline?

What colour does pH paper turn in neutral solutions?

What is the pH of neutral solutions?

Name one neutral solution.


Name


1a

The table below was copied from Universal Indicator paper (pH paper).

Describe how the pH of a solution can be measured using pH paper.

What colours does pH paper turn in acids?

What range of pH values indicates a solution is acidic?

What range of pH values indicates a solution is alkaline?

What colour does pH paper turn in neutral solutions?

What is the pH of neutral solutions?

Name one neutral solution.

1pH 2 3 4 5 6 7 8 9 10 11 12 13 14

red

pin

k

ora

nge

bei

ge

yello

w

lime

gre

en

gre

enne

utra

l

slig

htly

aci

d

very

aci

d

slih

tly a

lka

line

very

alk

alin

e

da

rk g

reen

turq

uois

e

pa

le b

lue

blu

e

da

rk b

lue

viol

et

pur

ple


Name


2

The following is a report given by SEPA to a fish farmer.

Describe how you would use Universal Indicator or pH paper to measure the pH of the water.

Give a name of a substance which could be used to neutralise the water.

Explain what is meant by neutralisation.

What happens to the pH of an acid as it is neutralised?

What happens to the pH of an alkali as it is neutralised?

What are the two products formed in a neutralisation reaction?

Explain why indigestion tablets are taken to relieve indigestion.

If you were stung by a wasp what would you use to neutralise it?


Name


3

The table below shows how long it takes 1g of each of the five metals to react completely inhydrochloric acid.

Write down the metals in order of reactivity (most reactive first).

1

2

3

4

5

Which of these metals react most strongly with water?

The reactivity of calcium is mid-way between those sodium and magnesium. How long might 1g ofcalcium take to dissolve in the acid?

Explain why copper rather than magnesium is used to make water pipes.Concentrate on reactivity in your answer.

copper

iron

magnesium

sodium

zinc

years

600s

35s

15s

180s

METAL TIME


Name


4

As a homework exercise, pupils were asked to find the pH values of a number of substances found inthe home. One pupil wrote down her results as follows:

Make a table to show whether these substances were acid, alkali or neutral.

Draw and label a diagram to show how copper can be obtained from the electrolysis of copperchloride.

Name one neutral substance, one laboratory acid and one laboratory alkali.

ACIDS ALKALISNEUTRAL

lemon juice 3 washing up liquid 8 window cleaner 12

indigestion tablet 10

vinegar 4 bicarbonate of soda 9 salty water 7

coffee 5 cola drink 5sugar solution 7

ACIDS AND METALS Level E: Glossary


Acids and MetalsGlossaryName

WORD MEANING

acid

alkali

neutralisation

pH scale

pH paper

Universal Indicator

solution

reaction

Reactivity Series

metals

displacement

electrolysis

electroplating

corrosion

extraction

electrode

ore

blast furnace

ACIDS AND METALS Level E: Glossary


Acids and MetalsGlossaryName

WORD MEANING

ACIDS AND METALS Level E: Pupil Checklist


Acids and MetalsPupil ChecklistName

By the end of this unit I should be able to:

Measure the pH of common solutions using pH paper and Universal Indicator.

State that acids have a pH value less than 7, neutral solutions have a pH value = 7 and alkalishave a pH value more than 7.

State that the lower the pH of an acid the greater the acidity; the higher the pH of an alkali thegreater the alkalinity.

State that acids and alkalis combine to form a neutral solution and adding acid lowers pH whileadding alkali raises pH.

State that when an acid neutralises an alkali, a salt and water is formed.

Give real life examples of neutralisation.

Plan and carry out a practical investigation on the differences in acid content in a range of softdrinks.

List metals in order of reactivity with oxygen, water and acid; potassium, sodium, calcium,magnesium, aluminium, zinc, iron, tin and copper.

Give examples of how reactivity relates to uses and sources of metals.

State that more reactive metals can displace less reactive metals from their solutions.

State that electrolysis can be used to obtain a metal from a solution.

Describe the effects of electroplating one metal with another using electrolysis.

Give examples of how some metals are extracted from their ores.

ACIDS AND METALS Level E: Resources and Safety Issues


Acids and MetalsResources and Safety Issues

A list of the resources required for this topic is given. The list is intended to give an overall feel of the nature and quality of

the resources required. Teachers should refer to the resources column in the Topic Guide which gives a list of resources

(per pupil/group) for each activity. The pupil numbers in each group and the number of pupils in the class will determine

the number of items.

There are relatively few hazards associated with the science activities outlined in the Glasgow Science Programme. For

those that do exist, the risks they present are readily controlled. Areas of safety to be aware of are outlined in the following

section but more detailed advice on all aspects of safety in science can be found in Glasgow City Councils Science Code of

Practice SSF/S1, Hazardous Chemicals Manual COSHH/8b and Be Safe (GSF/25, SSF/S31).

Teachers should follow advice given in these documents as well as exercise common sense when carrying out science

activities. Pupils too, should be made aware of potential hazards and be encouraged to consider these when planning

their own investigations.

If there is any doubt about safety issues during the teaching of this topic, consult Technician Resource Service (TRS), 135

Westmuir Street, Glasgow G31 5EX, 0141 554 6322 (or David Lawson, Adviser in Science, 0141 287 4126).

Teachers must ensure that proper risk assessments are undertaken for each activity that is relevant to their own

establishment. The following advice is taken from Be Safe and is suitable generic risk assessment for all activities.



Acids and MetalsResources Universal Indicator paper with colour chart.

Universal indicator.

pH meter or probe with interface.

Variety of common solutions e.g. lemon, lime, orange and grapefruit juices, vinegar, citric acid, cream of tartar, coffee,

tea, deionised water, salt solution, Epsom salts, milk, milk of magnesia, washing up liquid, bicarbonate of soda, weak

ammonia solution.

Beakers (50 ml, 100ml 250ml).

Safety glasses.

Droppers and dimple tiles.

Text books, CD ROMs, internet access.

10 ml syringes marked with red and blue tape.

HCl, H2SO

4, CH

3CO

2H (ethanoic acid), NH

3OH, NaOH (all solutions are 0.1M).

Evaporating basin.

Bunsen burner, tripod stand, heat resistant mats.

Stirring rods.

Indigestion tablets/powder.

Lime for putting on soil.

Soft drinks various acidities.

Measuring cylinders.

Safety screen.

Samples of fresh and partially corroded magnesium, zinc, iron, tin, copper.

Tongs.

Samples of metals for reactions: potassium, sodium, calcium, magnesium, aluminium, zinc, iron, tin, copper.

Test tubes and racks.

Copper sulphate solution and nickel sulphate solution for displacement reactions.

Copper (II) chloride, carbon electrodes, power pack and leads for electrolysis.

Lead bromide (demonstration of molten electrolysis).

Steel nail for electroplating, crocodile clips.



Acids and MetalsSafety Issues(Advice taken from Be Safe)

ChemicalsThe substances suggested for use in this topic can be used safely by pupils with the correct precautions but remember that

any substance, even salt can be harmful if taken in sufficient quantity. Be aware that any substance in a fine powdery or

dusty form can be inhaled and thus harm health.

Safety code for using chemicals When transferring solid chemicals use small spoons kept for this purpose, and not fingers. For liquids, use droppers

always taking great care to avoid cross contaminating the chemicals.

Only dispense small quantities so that it is never necessary to return excess chemical to the container.

Prevent contact with the eyes. This can happen when chemicals spit out of a tube during heating or when fingers are

contaminated with chemicals. Wear safety goggles/spectacles for such activities.

Avoid skin contact and use protective gloves if the information on the substance indicates it is corrosive or irritating to

skin or is poisonous by skin absorption.

Wipe away any spillage at once.

Always wash hands after using chemicals.

It may be dangerous to mix chemicals. Even inadvertent mixing in a sink, etc. of household chemicals, such as bleach

with other cleaners or acid can produce a toxic gas. Warn children of the dangers.

Safety code for storing chemicals Always store chemicals in containers securely labelled with the name of the chemical, and with a hazard warning

symbol if appropriate. It is best to use the original containers.

Be aware of the risk of confusion and avoid using food or drinks containers for the storage of chemicals.

Keep only small quantities of chemicals.

Keep a record of all chemicals stored.

Store all chemicals in a locked cupboard or room away from heat sources and separate from those intended as foodstuffs.

Store flammable liquids separately from other chemicals. Where there is more than half a litre of any one flammable, it

must be locked in a flame-resistant cupboard or store.

Disposing of chemicalsConsult the Technician Resource Service (TRS), 135 Westmuir Street, Glasgow G31 5EX (or David Lawson, Adviser in Science

0141 287 4126) if you wish to dispose of any chemicals.



Particular advice for this topicChemicalsThere are a number of acids and alkalis suggested for this topic. The concentration of these solutions should not exceed

0.1 M. In all experiments, safe classroom practice should be carried out at all times.

The acids and alkalis used can be safely disposed of down the drain, flushing well with water.

Reference should be made to the COSHH guidelines in the school (or contacts see above) if there is any doubt about

disposal.

Some pointers to remember when dealing with the chemicals are: Prevent contact with the eyes this can happen if

fingers are contaminated. Wear safety goggles/spectacles for all activities, wipe away any spillage at once and always wash

hands after use.

MetalsWhen testing the more reactive metals (Alkali metals) this should be done as a teacher demonstration.

The Multi Media Science School on the schools network has some nice video clips of the more reactive metals which you

can show. It also has a nice but very short clip of the electrolysis of molten lead bromide which you could show.

When heating the magnesium ribbon remind the pupils not to look directly at the magnesium as it can damage their eyes,

a beaker of cold water could be used to drop the copper in to after heating it.

When collecting the hydrogen gas for testing remind the pupils not to touch the bottom of the test tubes containing the acid

and metal as they will be warm, in some cases very warm!

ElectrolysisWhen carrying out the electrolysis experiments remember to ventilate the room to prevent a build up of chlorine gas, and

do not exceed 6V on the power pack when doing the experiment.

ElectroplatingWhen carrying out the electroplating experiments remind the pupils to be careful with the electroplating solution and to

rinse it off immediately if they spill it on themselves. Remember to switch off the power packs before handling the electrodes.

Further informationConsult Technician Resource Service (TRS), 135 Westmuir Street, Glasgow G31 5EX, 0141 554 6322 (or David Lawson, Adviser

in Science, 0141 287 4126).

acids and metals

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