Reaction speedsIf a metal reacts with water it is likely to react even faster withacids. Calcium fizzes more violently in acid than in water. Somemetals do not react at all. Gold stays shiny in water and in acidtoo. Gold is very unreactive.

Unreactive metals are used to make jewellery and coins and foruse outside in the weather.

Why does a gold bottle not corrode when it is filled withacid?

Gold never wears out so why is it not used for roofing?

Comparing reactivityMany metals react with acids and release bubbles of hydrogengas. We can use the rate of bubbling to compare the reactivityof metals. Reactivemetals bubble faster than unreactive metals.This allows a reactivity series to be drawn up of themetals that are tested.

Describe an investigation to find out which of twometals is the more reactive.

Describe an investigation to find out how much gasis released when a piece of metal reacts with anacid.

Developing a reactivity seriesWe can test metal samples with a variety of reagents such asoxygen, water, acids and alkalis. Comparison of the reactivities andthe products of the reactions allows us to construct a reactivityseries but there are problems. Aluminium appears unreactive, weuse it for window frames and tube trains. The metal is very reactiveindeed but it becomes coated in an unreactive layer of aluminiumoxide protects the metal underneath.

Iron goes rusty by reaction with oxygen and water. Whydoesn’t this rust coating stop any further corrosion?

... rate ... reactive ... reactivity

Metals and acidsMetals and acids

68

You are learning to:� Describe what you see

when metals react withacids

� Construct equations for thereactions

� Use evidence fromexperiments to makepredictions

BIG IDEASBIG IDEAS

FIGURE 1:Which metal, Aor B, is the more reactive?

A

B

Artists use acids and heattreatment to produce interestingcolour effects. Some metals suchas titanium can show a range ofcolours and surface patterns.Each piece made by the artist isunique. The technique allowsartists to be very creative.

Science in Practice

Scientists find it very usefulto place metals in order oftheir reactivity. By doing thisthey can predict whichmetals will be useful fordifferent jobs.

The reactivity of metals canbe compared by placing thesame-sized samples ofdifferent metals in thesame type and volume ofacid. By observing thenumbers of bubblesproduced, the metals can beplaced in order of their reactivity.

Your teacher will provide you with theapparatus that you may need foryour investigation.

Method:

1 Put four test tubes in a rack.

2 Add 2 cm3 of dilute sulphuric acidto each tube.

3 Add clean pieces of the fourmetals, one in each tube. Labeleach tube.

4 Observe and record the numbersof bubbles released in each testtube in a table.

Reactivity series

Questions1 Which was the most reactive metal?

2 What was the order of reactivity, starting with the most reactive metal? Write youranswer using symbols.

3 Where would you place gold (Au) in your series?

... reactivity series ... unreactive 69

FIGURE 1: Goldis used to makejewellery. Whyis this?

Planning exerciseHow could you find out if thereactivity series of Mg, Zn, Feand Cu with sulphuric acidresembles those with differentacids? These might includehydrochloric and phosphoricacids.Use similar pieces of theseparate metals and test withsolutions of the different acids.Control the concentrations andtemperatures of the acids.Compare the reactions, forexample in terms ofeffervescence.When particles of an acid collidewith metal particles, a reactionmay occur. In terms of particles,how would reactive andunreactive metals bedifferent?

70

Things have changed since the BronzeAge thousands of years ago – then peoplefound actual pieces of copper, oftenwashed down by streams. This wasnative copper, just the metal itself. Theleast reactive metals were discoveredfirst, for example copper, silver and gold.These three metals are all placed in thecentre part of the Periodic Table. BronzeAge people melted it with tin metal to formbronze. They used the bronze to makeweapons, axes and jewellery. Today, thereis very little native copper left. It has to beextracted from its ores (compounds ofcopper) that occur naturally in the Earth’scrust. In metallic ores, copper particles arecombined with other elements such asoxygen or sulphur. The copper particlesmust be chemically separated to give themetal itself. We call this smelting.

� Copper miners working 100 years ago inCornwall could expect to dig up ores thatcontained up to 10% copper. Today minersfind ores that contain less than 0.5% metal –this is all that is left.

� With a metal ore that is 99.5% waste, miningneeds to be carried out on a huge scale toproduce enough copper for wiring andplumbing needs. Copper and lead have somevery useful metallic properties. They aremalleable, conductors and easy to alloy withother metals to improve their properties.

� Copper is often extracted from its ore bysoaking it in sulphuric acid. This process iscalled leaching. It gives a blue solutioncontaining copper sulphate.

As metal ores become scarcer and more andmore expensive we need to find ways to makesupplies of essential metals last. Twopossibilities are:

� metal recycling

� the use of alternative materials.

Brass is an alloy of copper and zinc. Almost all ofthe brass used today is recycled material. Thisreduces the need for more mines producing newcopper and zinc. In plumbing, modern housesoften use plastic pipes as an alternative tocopper. This preserves limited supplies of themetal for essential uses such as electrical wiring.

Coppermining

An open-pit copper mine in the USA.

Copper wiring used in electric circuits.

8Your answersdemonstrate anextensive knowledge and

understanding of theproperties of materials and theEarth.

7Your answers show anadvanced understandingof the wide range of

processes related to the Earthand the properties ofmaterials.

6Your answers show thatyou can describeprocesses that relate to

materials and the Earth andthat you can use appropriateterminology

5Your answers show thatyou can describeprocesses related to

materials and the Earth, usingmore than one step or that youcan use a model to explain.

4Your answers show thatyou can describe someprocesses related to the

Earth and materials and thatyou understand the importanceof evidence.

71

Assess Yourself1 Which two metals are used to make bronze?

2 Give three uses of bronze.

3 What are natural compounds of metals called?

4 How much metal could you extract from 1000gof an ore containing 1% metal?

5 Why are copper mines operated on such a largescale today?

6 Why is brass a good example of conservation?

7 Give two ways in which supplies of metal orescan be conserved for the future.

8 What are the environmental gains of recyclingmetals?

History ActivityResearch theuses of bronzein the AncientWorld. Youmight considerbronze used incoins orjewellery orfor statuesand why itwas such agood materialto use.

Geography ActivityFind out where in the world the top threemajorproducers of a particular metal are located. You couldchoose from copper, aluminium or iron.

ConcentrationMany fruit drinks are very concentrated. They have a lot of fruitand sugar dissolved in water. A fruit drink can be diluted byadding water. After dilution, the concentrations of fruit and sugarare less.

What do we call a drink that has lots and lots of fruit andsugar dissolved in it?

How can you tell from the photograph below that the threeblackcurrant drinks are not equally concentrated?

Preparing solutionsSome acids are solids, for example citric acid and tartaric acid.Citric acid is found in lemon juice. If 1 g of citricacid is weighed out and dissolved in 100 cm3

water, the acid solution is quite dilute. Theconcentration of the acid solution is doubled bydissolving 2g of citric acid in the same volume ofwater. A range of acid concentrations can beprepared in this way.

It is not possible to tell the concentration of anacid solution just by looking at it – it is acolourless liquid. The reaction of a metal with anacid can be used to see the effects of changingacid concentration on the speed of a reaction.

Name one solid acid.

A solution of an acid contains 3g in 50cm3

water. How could you prepare a solution that ishalf as concentrated?

Predict how increasing the acid concentrationmight affect the speed of bubbling of a metalwith an acid.

... concentrated ... corrosive

Acidconcentration

Acidconcentration

72

You are learning to:� Explain how we change the

concentration of acids� Use the idea of particles to

explain how concentrationaffects the reaction speed

� Plan an investigation tofind the connectionbetween rate and concentration

BIG IDEASBIG IDEAS

FIGURE 2: How would you prepare a solutionof citric acid that is three times theconcentration of 1 g acid in 100 cm3 water?

Concentrated acids are oftenvery corrosive. They candamage the skin and the eyes.The best emergency treatmentfor an acid spillage is usuallyto add lots of water. Thisdilutes the acid andlowers itsconcentration.

The hazardsymbol indicatesan acid is corrosive.

FIGURE 1: Three different concentrations ofblackcurrant squash diluted with water.

Science in Practice

Comparing reaction speedsPlan an investigation to see if theconcentration of an acid affects the speedof a reaction.

Use this reaction for your plan.

Metal � acid a salt � hydrogen

A suitable metal to use is magnesiumribbon that can be cut into appropriatelengths.

Show how you would record your results.

... dilute ... solid 73

Questions

1 What conclusion can you make about the change in reaction speed (rate) withconcentration of acid?

Reacting particlesWhen acid particles collide with particles of magnesium metal, it is obvious that there is areaction. If you touch the tube, you notice that the temperature rises. As the particles reactto form products, heat energy is released.

2 How could you obtain some data for a graph based on the temperaturechanges with different concentrations of acid?

3 How is the surface of magnesium controlled in the above experiment and why doesit matter?

What experimental strategy might you use to investigate how the surface area ofmagnesium ribbon influences the rate of its reaction with acids?

FIGURE 1: Magnesiumribbon burning in oxygen.

Basketball competitionThere is always great competition to play for a sports team. Inbasketball, extra players wait to see if they get a chance to play. Thecoach can replace one player with another player. There are chemicalreactions where one metal is replaced by a different metal. The morereactivemetal displaces another metal. We can see changes whenone metal displaces another. These might be a change in the colour ora change in the temperature.

Which word describes what happens when one metal takes theplace of another?

Give one example of the kind of change there might be whenone metal replaces another.

Displacement reactionsWhen the reactivities of copper and iron are compared it is clear that iron is more reactive. Thecompound copper sulphate has a very distinctive blue colour. The two metals look very different too.Iron is silver-grey and copper is brown.

Reaction of an iron nail in copper sulphate solutionWhen an iron nail is placed in blue copper sulphate solution, changes are observed.

... displace ... displacement reaction

Displacement ofmetals

Displacement ofmetals

74

You are learning to:� Discuss how one metal can take

the place of another� Recognise that relevant

observations provideevidence

� Construct equations fordisplacements

BIG IDEASBIG IDEAS

FIGURE 1: The coach for thisbasketball team is replacingone player with another.

Material Start of reaction End of reaction

copper sulphate blue paler blue

iron metal silvery grey brown coating

Some of the iron in the nail has reacted with the coppersulphate solution.

iron � copper sulphate copper � iron sulphategrey blue brown very pale green

Some people have made moneyout of displacement reactions.Scrap iron is cheap but coppermetal is worth a lot of money.Old copper mines often becomeflooded and the water turnsblue. It is a solution of coppersulphate. Adding scrap iron tothe solution displaces coppermetal, a useful source of avaluable raw material.

So4 So4Cu

This displacement reaction takes place because iron is more reactive than copper. Amore reactivemetal displaces a less reactive metal from its solution. In this case, iron has displaced copper fromcopper sulphate.

Observations of similar reactions let us work out a reactivity series for metal displacements. Fromthis, we can predict which other displacements should be successful.

Why does the blue colour become paler in this investigation?

a What would be the final colour of this solution if all of the copper was displaced?

b Part of the reactivity series reads: Zn>Fe>Sn>Pb>Cu where > means more reactive than.How many of these metals could zinc displace? Explain your answer.

Displacement equationsZinc is more reactive than iron. This means that zinc can also displace copper from solutions such ascopper sulphate or copper nitrate.

The equations are very similar:

The reaction of zinc with copper sulphate works better if zinc powder is added to the blue solution.The powder provides a large surface area for reaction with the solution. Zinc powder is pale grey.There is a temperature rise as the displacement occurs. This is shown by placing a thermometer in thetest tube during the reaction.

Describe two changes you would expect when zinc powder is added tocopper sulphate solution.

Magnesium is more reactive than zinc. Write a symbol equation for thereaction between magnesium and copper sulphate solution.

Would anything happen if you added magnesium to a solution of zinc sulphate?Explain your answer.

Changing placesWhen metals displace each other from solutions, the particles rearrange themselves. The metalparticles that were originally in the soluble compounds are displaced as particles of the elementsthemselves. For example:

What can you conclude about the relative reactivities of magnesium and copper?

Write a symbol equation for the reaction of magnesium with zinc nitrate solution Zn(NO3)2where zinc is displaced.

Why is calcium metal of limited use in investigating displacement reactions of metals?

... reactive ... replace ... surface area 75

++++O O

O O

SO O

O O

SCu CuMg Mg

++++O O

O O

SO O

O O

SCu CuZn Zn

Predicting displacement reactionsIn chemical reactions we can often make predictions. If we have seen several reactions that aresimilar, we can predict other reactions we have not tried. If four different metals all fizz with acidswe might predict that another metal would fizz too.

By testing many metals to see how they react with oxygen, water or acids, we can develop areactivity series. The most reactive metals are written at the top with the metals becoming lessreactive down the list. More reactive metals displace less reactive ones. The reactivity series is usedto predict which displacement reactions will be successful.

... aluminium oxide ... displace

PredictingreactionsPredictingreactions

76

You are learning to:� Recognise that predictions can

be useful� Explain how to use data

to predict reactions� Construct equations to

match your predictions

BIG IDEASBIG IDEAS

Symbol Name Reacts with Reacts with Reacts withoxygen? water? dilute acid?

K potassium � �, fast in cold �

Na sodium � �, fast in cold �

Ca calcium � �, fast in cold �

Mg magnesium � �, slow in cold, �fast in steam

Al aluminium � �, needs steam �

Zn zinc � �, fast in steam �

Fe iron � �, fast in steam �

Pb lead � no �

Cu copper � no no

Au gold no no no

Does iron displace copper?The table above shows that iron is more reactive than copper.Therefore this displacement reaction can be predicted to besuccessful:

iron � copper sulphate copper � iron sulphate �

Does copper displace iron?The reaction between copper and iron sulphate can bepredicted not to be successful according to the data.

... predict ... reactivity series 77

copper � iron sulphate iron � copper sulphate �

a Which metal in the table do you predict could notdisplace any other metal?

b Name one metal that could displace magnesium frommagnesium sulphate solution but would be toodangerous to try. Explain why.

c Why should the surfaces of metals be cleaned beforetesting displacement reactions?

d Write both word and symbol equations for the reaction ofzinc with iron sulphate, FeSO4.

Describing displacement reactionsWith blue copper sulphate it is obvious if a displacement reaction has occurred because there is acolour change. Most solutions are colourless and there may not be a colour change. Often thereis a temperature change and this shows that a reaction has occurred.

Balanced symbol equations can be written– even for reactions that do not work.

Only one of the reactions shown by the equations above is predicted to work. It is the reactionbetween magnesium (Mg) and zinc sulphate (ZnSO4). From the data in the table on page 76magnesium is more reactive and displaces zinc.

Write a word equation for the reaction between zinc and lead nitrate solution.

Write a symbol equation for the reaction between magnesium and iron sulphate.

Predict if the reactions in Q2 and Q3 will be successful.

Particles and bondsThe number of metal particles that can combine with sulphate particles can vary. Metals canhave different numbers of bonds to combine with other groups or elements. For example:

Sodium sulphate Na2SO4

Zinc sulphate ZnSO4

Aluminium sulphate Al2(SO4 )3

We need to find out the numbers of bonds before writing more difficult chemical formulae.The sulphate particle in the examples has two bonds.

Zn � MgSO4 ZnSO4 � MgMg � ZnSO4 MgSO4 � Zn

Would you predict that reactivealuminium would be a badchoice for use as cooking foil ina hot oven? Aluminium is highin the reactivity series andshould react with food or drink.But it does not. Aluminiummetal is covered in a thin layerof aluminium oxide that stopsit reacting further. This is anexample of a prediction notbeing enough – a reaction mustbe carried out to test theprediction.

What is rust?Cars are made from steel. Steel is mostly made fromthe element iron. The problem with iron is that itrusts. If the paint chips off a car, the iron underneathstarts to go rusty. Rust can even spread under paint.Rusty iron is brown in colour. Iron loses its strength as itgoes rusty. This is why rusty cars become unsafe to driveand end up in a scrap yard.

Which element that is in steel goes rusty?

Describe two changes to iron caused by rusting.

The golden alternativeRusting is just one example ofcorrosion. When somemetals react with air andwater they start to corrode.They lose their shinyappearance and become dull.In some cases the corrosioncontinues until no metalremains, as with iron.

But some metals resistcorrosion. They are unreactivemetals that are not affected by air orwater, or metals that react extremely slowly. Examples of unreactivemetals are gold and platinum. A golden car would never corrode but itwould be too expensive and also very heavy! Copper and lead corrodeslowly but are still used for roofing.

Copper jewellery also corrodes slowly – it turns green. It can even stainyour skin green too.

Aluminium is the shiny metal we use for cooking foil. It does not seemto corrode, even at high temperatures inside an oven. Aluminium is aspecial case. The metal reacts rapidly with oxygen in the air to formaluminium oxide which protects the metal underneath fromfurther corrosion.

... alloyed ... corrosion ... element ... rust

Corrosion ofmetals

Corrosion ofmetals

78

You are learning to:� Recognise that iron goes rusty

in certain conditions� Explain why some metals do not

corrode� Make connections

between the availabilityand uses of metals

BIG IDEASBIG IDEAS

FIGURE 1: Rusty cars end up in scrap yards.Why are rusted cars unsafe to drive?

FIGURE 3: St Paul’s Cathedral inLondon. What is its dome made from?

FIGURE 2:Why does gold jewellerystay shiny whereas copper jewelleryeventually turns green?

Give two examples of metals that resist corrosion.

What colour change is seen when copper corrodes?

Suggest how acid rain affects the speed at which metalscorrode.

Making the right choiceMetals that resist corrosion have special uses. Gold, silver andplatinum are all used to make jewellery, coins and medals. It isimportant that metals chosen for these objects do not corrode,for example iron coins would be unsuitable. Fine gold wires areused in computers. If these wires corroded, data would be lost orthe computer might stop working.

Iron can be made to resist corrosion if it is alloyed (mixed) withchromium and nickel which gives stainless steel. This shiny alloyis used for cutlery and for the insides of washing machines and inhospitals where corroded metals might harbour germs.

Name two metals that are used in coinage.

Which elements are alloyed with iron in stainless steel?

a Why are the insides of dishwashersmade from stainless steel?

b Where in the reactivity series wouldyou find metals such as gold andplatinum?

c Why are you unlikely to readequations that show gold displacinganother metal?

d Write a word and symbol equationfor the reaction of sodium with silvernitrate solution, AgNO3 solution.What problems might you find intesting this reaction?

Why use steel?Both iron and steel go rusty and yet we still use steel to make millions of cars each year. There areseveral reasons for choosing steel. Steel is a low-cost construction material compared withalternatives such as aluminium or stainless steel. Steel is malleable and very strong. Both galvanising(zinc coating) and painting can slow down the rusting process.

If the nitrate particle has a single bond to attach to other things, how many bonds must beformed by aluminium and by silver in this equation?Al + 3AgNO3 Al(NO3)3 + 3Ag

... stainless steel ... steel ... unreactive 79

The metal titanium is used forsome replacement body parts.People whose knee joints need tobe replaced can have a titaniumhinge joint. Titanium does notcorrode inside the body.

FIGURE 4:Why are hospital surfacesoften made from stainless steel?

Keeping iron dryThe things that make iron rust are:

water air (oxygen).

... anodising ... corroding ... galvanised iron

How to stopcorrosionHow to stopcorrosion

80

You are learning to:� Decide how to stop iron from

rusting� Discuss the factors that affect

rusting� Compare the range of anti-

corrosion methods

BIG IDEASBIG IDEAS

Dry iron does not go rusty. In a desert there is very little waterand so iron hardly rusts at all.

In our climate we need ways of keeping iron dry to stop itfrom rusting.

Iron can be painted, for example cars and trucks.

Iron can be covered in plastic, for example a washingline or clothes-drying rack.

Iron can be covered in grease or oil, for example abicycle has oil or grease put on its iron chain.

All of these methods work by keeping water away from iron.

Why do cars not go rusty in deserts?

a How can you stop a bicycle chain from rusting?

b Water cannot soak through plastic or grease. Explainwhy this helps keep bicycle chains shiny andplastic-coated steel washing lines in new condition.

Zinc to the rescueIron and steel can be coated with zinc to stop the ironunderneath corroding. The process is called galvanisingand the product is galvanised iron.

In the 19th Century much of thecentre of Paris was rebuilt. Thearchitect chose zinc sheeting asthe roofing material. Zinccorrodes very slowly and producesan attractive grey surface, calleda patina. These zinc roofs canlast for up to 100 years and havebeen favourite subjects for artistsin Paris to paint.

The steel cables supporting theForth bridge are slowly corrodingand some thin wires have alreadysnapped.Engineers are pumping a currentof dry air through the cables tostop the corrosion. Without this,the bridge might collapse.

Forth road suspension bridge,near Edinburgh in Scotland.

FIGURE 1: These have not rustedbecause the climate is dry.

For iron to rust oxygen and water must bepresent. If either oxygen or water is excluded,the iron does not corrode. The zinc coatingexcludes oxygen and water.

An example of galvanising is in iron roofingsheets and nails. They are coated with zinc toprotect them from the weather. (Zinc is tooweak to make nails.)

Food cans are often called ‘tins’ because thesteel can is covered with a thin layer of tin.This prevents the steel from corroding andpossibly reacting with the food inside the can. Zinc cannot be used forcans because some foods dissolve the zinc coating.

What is the corrosion coating called that forms on some metals?

Tin follows iron in the reactivity series. Why is this a problemwhen a tin-plated steel can is scratched?

The sunken wreck of the ship The Titanic is surrounded bycold seawater. Why has the wreck not rusted away completely?

Stopping the rotAluminium does not corrode because it has a coating of aluminium oxide on itssurface that is unreactive. This coating can be improved by anodising the metal.During this process an aluminium object is placed in a special electrical cell thatproduces oxygen and this strengthens the surface coating. The coating can absorbbright colours. We see examples of this in Christmas decorations and in cookware.

Most cars are now partly galvanised to resist corrosion. Many layers of paint aresprayed on to further protect the steel underneath. Some modern cars are madecompletely from aluminium, just like aircraft and underground trains. Thealuminium does not need to be painted. Stainless steel planes would be too heavyeven to take off.

Give two ways in which cars can be protected from corrosion.

Why might you describe a steel plane as an ‘expensive caravan’?

Designer problemsAluminium cars do not go rusty, unlike steel. The reactive aluminium is protected byan impermeable surface layer of aluminium oxide that protects the metal. However,aluminium is much more expensive than steel to produce. We could also use theunreactive metal titanium to build cars but they would cost a fortune to buy.

Aluminium requires large amounts of expensive electricity to extract frombauxite ore. Why is this an argument in favour of recycling drinks cans?

... galvanising ... patina 81

FIGURE 2: Galvanised iron roofingsheets. Why is it necessary to galvaniseiron materials that are used outside?

FIGURE 3:Why isaluminium anodised? Whydo anodised aluminiumobjects look attractive?

For each of the following statements write ‘T’ if the statement is true or ‘F’ if it isfalse.

a Iron needs water and air to rust.

b Rusting is not an example of corrosion.

c Metal ores are natural compounds.

d Gold coins never rust.

Copy and complete the sentences using the words below.

equations gold more series

a Some metals are ____________ reactive than others.

b A reactivity __________ shows how the properties of metals compare.

c One metal that is found as a pure metal is ______________ .

d We can show what happens in a reaction using ______________ .

Write down the correct description for each word.

displacement corrosion of iron

dilution speed of reaction

rusting take the place of

rate adding water to a solution

Write down the correct metal for each use.

Metal: Use:

gold drinks can

aluminium steel in cars

copper jewellery

iron electrical wiring

Grey zinc powder is added to a blue solution of copper sulphate. The solid changescolour to brown and the solution becomes colourless. For each of the followingstatements write ‘T’ if the statement is true or ‘F’ if it is false.

a Zinc has displaced copper.

b The final solution contains zinc sulphate.

c Zinc is less reactive than copper.

d A finer zinc powder would react more slowly.

Practice questions

82

Copy and complete the equations below.

a sodium + water sodium hydroxide + _________

b iron + ___________ + air rust

c magnesium + copper sulphate _________ + magnesium sulphate

d aluminium + iron oxide iron + aluminium ____________

Use the following reactivity series to write ‘T’ if a statement below is true or ‘F’ if itis false.

K Na Ca Mg Zn Fe Pb Cu Au

a The most reactive metal is potassium.

b Magnesium can displace lead from solution.

c The reactivities of zinc and of iron are similar.

d The metal least likely to be found as a native element is gold (Au).

a Why do gold objects usually provide more detailed information to archaeologiststhan iron objects?

b What is special about the soil at Sutton Hoo that affected the preservation of the

burial goods?

c Why do we extract copper from ores that contain only 0.5% copper minerals?

d Why are copper mines so big?

Copy and complete and balance the following equations.

a Na + H2O NaOH + __________

b K + H2O ________ + __________

c Mg + O2 MgO

d Ca + ________ CaO

Aluminium is found towards the top of the reactivity series of metals.

a What is formed when aluminium reacts with oxygen?

b What is the formula of the product?

c Why does the aluminium in a drinks can not react with the contents?

83

Topic Summary

� I know that some groups of metals have special names. page 62

� I know that iron rusts. page 78

� I know that acids react with metals. page 64

� I know that gold is unreactive. page 68

� I know what ‘concentrated’ and ‘dilute’ mean. page 72

� I know how the alkali metals react with water. page 62

� I know that rusting is an example of corrosion. page 78

� I know that metals react at different rates with acids. page 68

� I know why gold is chosen to make jewellery and coins. page 78

� I know how to vary the concentration of an acid. page 72

� I know that the Earth’s supply of metals is limited. page 78

� I know the reactivity trend for the alkali metals. page 63

� I know that reactivity is linked to rate of corrosion. page 78

� I can draw up a reactivity series of metals. page 68

� I can decide which metal to use based on reactivity. page 79

� I can predict the outcomes of displacement reactions. pages 74–75

� I can write and interpret word equations. page 64

� I can predict the reactivity of the alkali metals from data. page 63

� I can understand how to prevent metals corroding. page 79

� I can interpret the behaviour of metals in terms of the reactivity series. page 69

� I can understand the importance of gold in archaeology. pages 60-61

� I can write symbol equations for displacement reactions. page 75

� I can assess the importance of recycling in the conservation of metals. page 81

� I can use both scientific and economic data to decide on how best to page 81use metals

� I can interpret formulae and equations in terms of the numbers of bonds page 77used by the particles involved.

84

85

1 Which metal goes rusty?

2 Name one yellow metal that does notcorrode.

3 Why does a new car not go rustywhen left in the rain?

4 How can you dilute an acid?

5 What do you see when magnesiumreacts with an acid?

6 Which gas is produced when reactivemetals are placed in an acid?

7 Which group of metals includessodium (Na) and potassium (K)?

8 What happens in a displacementreaction?

9 What does ‘reactivity series’ mean?

10 How much copper ore is contained inthe material mined from most coppermines?

A 5% B 0.5% C 2.5%?

11 What happens when copper ore isleached?

12 What is the link between acidconcentration and rate of reactionwith metals?

True or False?

If a statement is false then rewrite it so it iscorrect.

1 Alkali metals include sodium andpotassium.

2 Alkali metals are not very reactive.

3 Rusting is an example of corrosion.

4 Iron needs only water to rust.

5 Magnesium is more reactive thancopper.

6 Copper can displace magnesium fromsolution.

7 An acid can be made moreconcentrated by adding water.

8 A reactivity series allows reactions tobe predicted.

9 Symbol equations give us moreinformation than word equations.

10 A low-grade copper ore contains lessthan 0.5% copper.

11 Scrap iron can be used to recovercopper from solutions containingcopper sulphate.

12 The compound formed in the reactionbetween potassium and water is KOH.

Topic Quiz

Literacy ActivityWrite the text for a poster urging people to recycle aluminium drinks cans. Make it clear whatthe environmental benefits would be.

ICT ActivityUse the British Museum website to research the range of metal objects discovered at theSutton Hoo ship burial site. Display your results to show examples and write a brief descriptionof each one.