A community of VALUED individuals V Aspirational Learning ......Acids and metals I can describe what happens when metals react with acids. I can compare the reactions of different

1

Chemistry– Metals + acids Name …………………………………………………………………….

Part I was present

for this lesson

(tick)

Red, amber or

Green?

R A G

1 3.1 Acids and metals

2 3.2 Metals and oxygen

3 3.3 Metals and water

4 3.4 Metals displacement

5 3.5 Extracting metals

6 3.6 Ceramics

7 3.7 Polymers

8 3.8 Composites

9 3.9 Chapter summary

Mini test 1 Mark: Grade:

Successes in this topic:

Developments:

A community of VALUED individuals

Versatile Aspirational Learning Understanding Engaged – Determined

2

Learning homework for this topic: This will be on Show My Homework. Please ask you parents to sign that you have been learning it. A good way would be to make a poster.

Probably done in yr. 10 for most groups.

3

Key word Definition

carbon fibre A material made of thin tubes of carbon.

ceramic A compound such as a metal silicate or oxide that is hard,

strong, and has a high melting point.

composite A mixture of materials with properties that are a combination

of those of the materials in it.

displace A more reactive metal displaces – or pushes out – a less

reactive metal from its compound.

displacement reaction In a displacement reaction, a more reactive metal displaces

– or pushes out – a less reactive metal from its compound.

metal

Elements on the left of the stepped line of the Periodic Table.

Most elements are metals. They are good conductors of

energy and electricity.

natural polymer Polymers made by plants and animals, including wool,

cotton, and rubber.

ore A rock that you can extract a metal from.

polymer A substance made up of very long molecules.

reactive A substance is reactive if it reacts vigorously with substances

such as dilute acids and water.

reactivity series A list of metals in order of how vigorously they react.

state symbol

A state symbol gives the state of a substance in a chemical

equation. (s) means solid, (l) means liquid, (g) means gas,

and (aq) means dissolved in water.

synthetic polymer A substance made up of very long molecules that does not

occur naturally.

thermite reaction Reaction of aluminium with iron oxide to make aluminium

oxide and iron.

4

CWK How do metals react with acid? ………/……./………..

Lesson Developing Secure Extending

C2 3.1

Acids and metals

I can describe what

happens when metals

react with acids.

I can compare the

reactions of different

metals with dilute acids.

I can use formula

equations to show what

happens when metals

react in different acids.

I can state that hydrogen

gas makes a squeaky pop

when lit.

I can explain the test

for hydrogen gas.

I can use word and

formula equations to

explain the test for

hydrogen gas.

A. The products in the reaction

between a metal and an acid are a

salt and ………………………………… gas.

B. The test for hydrogen gas is

…………………………………………………………….

…………………………………………………………….

…………………………………………………………….

…………………………………………………………….

…………………………………………………………….

Key words

hydrogen lit splint squeaky pop test tube acid salt

5

Reacting metals with acid

Setting the scene

When metals react with acids they form a salt and hydrogen. But not all metals react

readily with acid. You will use the signs of a reaction to identify which metals react

more readily, and which react least readily.

Aims

In this practical you will:

react four different metals with an acid to decide which react most vigorously

make observations of the reactions to decide how vigorously the reactions are

occurring. You will be working scientifically to:

interpret your observations to decide which metal reacts most vigorously with acid

make and record observations

present observations using tables

use appropriate methods, paying attention to associated risks.

Safety

Wear eye protection throughout the practical and wash spills off skin immediately.

Magnesium is flammable. Keep away from naked flames.

Iron filings can be irritating to eyes. Do not rub your eyes. Clear up unused iron

immediately.

Lead is toxic. Wash your hands after handling.

Take care when handling test tubes as they can become hot and bubble during the

experiment.

Equipment and materials

eye protection, 0.5M hydrochloric acid, test tubes, zinc, lead, iron, magnesium ribbon,

test-tube rack, copper sulphate solution

Method

1 Put 2cm of acid into a test tube.

2 Place a small piece of magnesium ribbon into the acid.

4 Wait for a few minutes and draw what happens - draw how many bubbles you see.

5 Repeat the method using zinc, lead, and iron.

Results – draw what happens:

6

Metals Observations

Magnesium

Zinc

Iron

Lead

Questions

1 Tick the observations that suggested a reaction was occurring. Challenge

The acid fizzed and bubbles were given off.

The metal changed colour.

The same amount of acid was used for each experiment.

The temperature of the acid went up.

Mg Magnesium Zn Zinc Fe Iron Pb Lead

7

2 List the four metals in order of increasing reactivity with the acid. Put 1 for the most

reactive, 2 for the second most reactive and so on. Extra challenge.

Magnesium ………………….

Lead ………………….

Iron ………………….

Zinc ………………….

Explain how you decided the order they should be in.

E.g. I chose magnesium as …………………………………………… reactive because it gave the most

………………………………………. when added to acid.

3 How you can find out if you have produced hydrogen gas. Super challenge.

Use a glowing spill, if it is hydrogen it will relight

Use a lit spill, if it is hydrogen there will be a squeaky pop.

Use limewater, if it is hydrogen it will turn the limewater cloudy.

When an acid reacts with a metal a salt and water are formed.

Acid + metal salt + water

If the metal reacted with citric acid then a metal citrate was made. Super challenge +

The type of acid used decides which salt you get.

Hydrochloric acid makes a CHLORIDE

Sulphuric acid makes a SULPHATE

Nitric acid makes a NITRATE

4 Complete the following word equations for the reactions between the four metals

and hydrochloric acid:

magnesium + hydrochloric acid → ……………………………….. + …………………………………

zinc + hydrochloric acid → ………………………………… + ………………………………………….

lead + hydrochloric acid → ……………………………….. + …………………………………………..

iron + hydrochloric acid → ……………………………….. + …………………………………………...

8

What have you learned this lesson?

This lesson I learned about:

………………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………………… Prove it tasks for 3.1

Choose your question

Summary questions

Extra challenge Super challenge

9

B) The label on a bottle of kitchen cleaner says:

It leaves kitchen and bathroom surfaces bright and shiny.

Another part of the label says:

Contains sulphamic acid

Irritating to eyes and skin

Keep out of reach of children

(i) The chart shows the colour of universal indicator in different solutions.

type of solution strongly acidic

weakly acidic

neutral weakly alkaline

strongly alkaline

colour of universal indicator

red orange green blue purple

What colour will the kitchen cleaner turn universal indicator?

..................................................................………. 1 mark

(ii) Which hazard label do you expect to see on the bottle? Write the correct letter from the list above.

............................................…

1 mark

Maximum 4 marks

CWK How do metals with oxygen? …………/………/…………………..

10


C2 3.2 Metals and oxygen

I can state the product of

the reaction between

metals and oxygen.

I can compare the

reactions of different

metals with oxygen.

I can explain the

reactivity of metals

according to how they

react with oxygen.

I can identify state

symbols from an equation.

I can use state symbols

in balanced formula

equations.

I can construct balanced

equations that include

state symbols.

A. i) The state symbol for a

substance in the gas state is

…………………………

(s) means ……………………………

ii) Predict the symbol for a

substance in the liquid state

…………………………………………………..

B.

Meta l i) …………………………………………………

Metal ii) ………………………………………………..

iii) Give the word equation for calcium

reacting with oxygen: ……………………. + oxygen ………………………………………

How do metals react with oxygen? demonstration

Key words

gas solid liquid magnesium zinc calcium calcium oxide magnesium oxide

11

Setting the scene

Some metals react more easily with oxygen than others. You can usually tell which

metals react more easily by watching them burn.

Aims

In this practical you will:

Watch your teacher react metals with oxygen by burning them in air

record your observations to decide which metal reacts most easily with oxygen.

make and record experimental observations

interpret your observations to decide which metal reacts most vigorously

present explanations of your conclusions.

Safety - Wear eye protection throughout the practical demonstration

Magnesium is highly flammable. Do not look directly at burning magnesium.

Iron filings can be irritating to eyes.

Calcium is highly flammable. Do not look directly at burning calcium.

Your teacher may ask you to sit behind a safety screen for parts of the

demonstration.


eye protection, magnesium ribbon, iron wool, copper strips, aluminium strip/foil,

black tongs, test tubes, heatproof mat, safety screen

spirit (methanol or ethanol) burner

Use this table to record your observations.

Metal

reacting Observations Equation to represent the reaction

iron

Iron + oxygen iron oxide

……. + ………. …………………..

aluminium

Aluminium + oxygen …………….. oxide

……… + ………. …………………..

copper

Copper + ……………… copper oxide

…… + ………. …………………..

magnesium

magnesium+ …………….. ……………..oxide

………. + ………. ……………………..

Prove it task 2

12

Choose from the following list of chemical formulae to help you complete the word

equations [super challenge] and symbol equations [Super challenge +] :

Oxygen copper oxide magnesium oxide aluminium oxide

Mg Cu Al Fe O2 FeO Al2O3 CuO MgO

Extension. You may include state symbols in your equations.

State symbol Meaning Example

(s) solid copper strips

(l) liquid water

(g) gas oxygen

(aq) aqueous solution salty water

……………………. + ………………………. …………………………………

……………………. + ………………………. …………………………………

……………………. + ………………………. …………………………………

……………………. + ………………………. …………………………………

Method for teacher demo.

1 Collect one sample of each metal and a pair of tongs.

2 Holding each sample using the pair of tongs, heat in a blue flame for 30 seconds

to a minute.

3 Record your observations about each reaction in an appropriate results table.

4 Write an equation to represent the reactions you have seen. Include state symbols.

Questions

1 List the metals in order of how well they reacted with oxygen. Start with the most reactive

metal.

Most reactive ………………………………………

……………………………………..

……………………………………..

Least reactive ……………………………………..

13

2 Explain how your observations helped you to put the metals into the order in

Question 1.

Extension

1 Explain what reactive means.

2 Using your observations, complete the following sentences:

is more reactive than but less

reactive than .

I know this because

3 Lithium reacts explosively with oxygen in a Bunsen burner flame. Use this

information and your observations above to predict the reactivity of lithium

compared to the metals you have observed in this practical. Explain your answer.

14

Summary /Prove it Tasks

1. Complete the sentences.

Some metals burn vigorously in air, for example ……………………………. The products are

Metal ………………………………. Some metals form an oxide layer on their surface when heated,

for example …………………………………….. Some metals, for example ……………………………….. , do not

react with oxygen. (4 marks)

Extra Challenge

…………………………… + ………………………………….. ……………………………………………

Super Challenge

…………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………

gold copper magnesium oxide

15

Creative Challenge

…………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………


………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

16

CWK How do metals with water? …………/………/…………………..

Developing Secure Extending

C2 3.3 Metals and water

I can state the products

of the reaction between

metals and water.

I can compare the

reactions of metals with

water.

I can link a metal’s

reaction with its place in

the reactivity series.

I can state whether a

metal is more or less

reactive than another

metal.

I can use the reactivity

series to predict

reactions.

I can explain predictions

made about a metal’s

reactivity.

A. The products of the

reaction of calcium and

water are:

…………………………………….. and

…………………………………………….

B. What are the state

symbols for substances in

the following states:

Liquid

…………………………….

Dissolved in water

……………………………………….

Key words

water hydrogen calcium hydroxide solid liquid gas (s) (l) (g) (aq) steam

17

C Name two metals that react

with steam but not cold water:

……………………………………………………………

...Na + .…H2O .…H2 +

.…NaOH

…………………………………………………………………………………………………………………

..

…………………………………………………………………………………………………………………

.

…………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………

.

………………………………………………………………………………………………………………..

18

…………………………………………………………………………………………………………………

.

Reacting metals with water

Setting the scene

When metals react with water they form an oxide or hydroxide, some produce

hydrogen. But not all metals react with water.

You will use the signs of a reaction to identify which metals react more readily, and

which react least readily.

Aims - react four different metals with water to decide which react most

vigorously

make observations of the reactions to decide how vigorously the reactions are

occurring.

Safety

Wear eye protection throughout the practical and wash spills off skin immediately.

Take care when handling test tubes as they can become hot and bubble during the

experiment.


eye protection, , test tubes, pieces of: zinc, lead, iron, magnesium ribbon, test-tube

rack, copper sulphate solution

Method

1 Put 2cm of water into a test tube. Label the tube magnesium.

2 Place a small piece of magnesium ribbon into the water.

4 Wait for a few minutes and draw what happens - draw how many bubbles you see.

5. Leave the tube to see if anything happens.

5 Repeat the method using zinc, lead, and iron. Label each tube with the metal it has in it.

6 leave the tubes until next lesson to see how they have changed

Results – draw what happens:

19

Metals Observations

Magnesium

Zinc

Iron

Lead

Questions/Prove-it tasks

1. Describe what you might see if a reaction has happened. Challenge

…………………………………………………………………………………………………………….

…………………………………………………………………………………………………………….

2. a) List the four metals in order of increasing reactivity with the water. Put 1 for the most

reactive, 2 for the second most reactive and so on. Extra challenge.

Magnesium ………………….

Lead ………………….

Iron ………………….

Zinc ………………….

Mg Magnesium Zn Zinc Fe Iron Pb Lead

20

b) Explain how you decided the order they should be in.

E.g. I chose magnesium as …………………………………………………………………………………………………..

……………………………………………………………………………………………………………………………………………….

3. How you can find out if you have produced hydrogen gas. Super challenge.

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

4. Explain what could you do to stop a metal reacting with water? Super challenge +.

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

……………………………………………………………………………………………………………………………………………….

Metal corrosion oxygen oxide paint grease anodised

Galvonised sacrificial protection



………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

21

CWK What is a displacement reaction? …………/………/…………………..

A. A displacement reaction is

when a ………………………… reactive

metal displaces (pushes off) a

less ………………………………… metal.

B. State why copper cannot displace

magnesium in magnesium sulfate

solution.

……………………………………………………….

…………………………………………………………

In a displacement reaction a

……………….

Reactive metal pushes out a

……………….

Reactive metals from its compound.

For example ………………………. displaces

………………………………….. from

……………………….. oxide.

Developing Secure Extending

C2 3.4

Metal displacement

reactions

I can state which metal is

more reactive in a pair of

named metals.

I can predict if a given

pair of substances will

undergo displacement.

I can explain why

displacement reactions

are predicted to occur or

not occur.

I can state where

different metals are

found in the reactivity

series.


series to explain

displacement reactions.

I can use particle models

and diagrams to

represent displacement

reactions.

Key words

more less reactive metal solution compound oxide aluminium iron

22

Will a displacement reaction occur?

Setting the scene

The reactivity series lists metals in order of how reactive they are. More reactive metals are

able to displace less reactive metals from their compounds. This is a displacement reaction.

Safety

Wear chemical splash-proof eye protection throughout the practical activity.

If any chemicals get onto your skin, wash these off immediately and inform

your teacher.

Magnesium is flammable. Keep it away from naked flames.

Lead foil is toxic and is hazardous to the environment. Dispose of it as directed by your

teacher.

Zinc nitrate is harmful and oxidising. Keep this away from sources of heat and wash any

spills off your skin immediately.

Magnesium nitrate is oxidising.

Copper nitrate is harmful.

Lead nitrate solution is toxic.


eye protection [goggles], magnesium pieces, zinc pieces, copper pieces, lead pieces,

zinc nitrate solution, magnesium nitrate solution, copper nitrate solution, lead nitrate

solution, test tubes or spotting tile, test-tube rack, pipettes

Hypothesis

Which of the following statements describes what happens if a displacement reaction

takes place?

a A less reactive metal will displace a more reactive metal from its compound.

b A more reactive metal will displace a less reactive metal from its compound.

Method

1 Place a small piece of your first metal into four separate test tubes.

2 Add 1 cm3 of magnesium nitrate solution to one of the test tubes using a dropping pipette.

Record your observations.

3 Repeat Step 2 using zinc nitrate, copper nitrate, and lead nitrate, using a clean test

tube containing a fresh piece of metal and a clean pipette each time.

4 Now repeat Steps 1–3 for zinc, copper, and lead.

23

5 Fill in the table below to show whether a displacement reaction happened for each metal–

metal compound combination.

Use ticks to show pairs that had a displacement reaction and crosses to show those that

did not react.

Substance magnesium zinc copper lead

magnesium nitrate x

zinc nitrate

x

copper nitrate

x

lead nitrate

x

6 Explain why it is not necessary to react a metal with a solution of its own compounds. For

example, why is it not necessary to react copper with copper nitrate?

24

7 Write a word equation for each of the displacement reactions you observed occurring.

Example:

Magnesium + zinc nitrate magnesium nitrate + zinc

Magnesium + ……………………. nitrate magnesium nitrate + …………………

Magnesium + ……………………. nitrate magnesium nitrate + …………………

Zinc + ……………………. nitrate ……………………………… nitrate + …………………

Extension

1 Explain, using particle diagrams, what happens during a displacement reaction.

25

2 Write a balanced formula equation for each displacement reaction you have

identified in Question 4 above. Include state symbols in your equation.

Choose from the following list of possible chemical formulae:

Mg Mn Zr Zn Co Cu Pb Ph

Mg(NO3)2 Mn(NO3)2 Zr(NO3)4 Zn(NO3)2 Co(NO3)2

Cu(NO2)2 Pb(NO3)2 Pb3(PO4)2

……………………….. + ………………………… …………………………………………….. + ……………………………….

……………………….. + ………………………… …………………………………………….. + ……………………………….

……………………….. + ………………………… …………………………………………….. + ……………………………….

……………………….. + ………………………… …………………………………………….. + ……………………………….

……………………….. + ………………………… …………………………………………….. + ……………………………….

……………………….. + ………………………… …………………………………………….. + ……………………………….

26

Summary questions/Prove it tasks

a) React yes/no.

Because …………………………………………………………

………………………………………………………………………….

b) React yes/no.

Because …………………………………………………………

………………………………………………………………………….

c) React yes/no.

Because …………………………………………………………

………………………………………………………………………….

a) React yes/no.

Because …………………………………………………………

………………………………………………………………………….

27

CWK How are metals extracted from their ores ? …………/………/…………………..

A. An ore is a ………………………… that

you can extract a

………………………………. from.

B. Describe two stages in

extracting a metal from its

ore.

1. ……………………………………………………………

………………………………………………………………..

………………………………………………………………..

2. ……………………………………………………………

………………………………………………………………..

………………………………………………………………..

………………………………………………………………..

1. Underline the correct word and

cross-out the incorrect word.

……………………………………………………………………….

C2 3.5

Extracting metals

I can state where carbon

is found in the reactivity

series.


series to decide which

metals can be extracted

from their ores by

heating with carbon.

I can explain why metals

can be extracted using

carbon, using the idea of

displacement.

I can calculate the

percentage of waste

material in a metal ore.

I can calculate the

amounts of metals in

ores.

I can convert amounts of

metals within ores from

masses to percentages,

or vice versa.

Key words rock metal separate oxide ore chemical charcoal carbon dioxide

28

How were metals extracted in the past?

Setting the scene

Many metals can be extracted from their ores. Ores are compounds that contain metals

combined with other elements. Metals such as iron have been used for many

thousands of years but how did people first get to this metal?

Aims

In this activity you will:

look at an early method for extracting iron from iron ore

use your knowledge of extracting metals to explain why this method works.

You will be working scientifically to:

present explanations of data.

Task

In Europe, around 900 BC, iron could be extracted using the following method. Read

the method and then answer the questions below.

29

Questions

1 Write the name that would be given to the rocks described in Step 1 of the method.

2 Suggest why wood or charcoal needs to be added to the fire or oven.

3 Write a word equation to represent the reaction that is happening in the above

method. Assume the iron ore is iron oxide only.

4 Use your knowledge of the reactivity series to explain why the above method could

be used to extract iron but not aluminium.

30

31

Extension

1 Write a formula equation to represent the extraction of iron described above.

Assume the formula for iron oxide is FeO. Include state symbols in your equation.

2 Suggest why iron artefacts, such as jewellery, appeared much later in history than those made

from gold but much earlier than those made from aluminium.

Hint: you may use the reactivity series to help you.

3 Sadie has 10 g of brucite and 50 g of dolomite, which are both magnesium ores.

If brucite contains 41 % magnesium by mass and dolomite contains 13 % magnesium

by mass, which sample will give Sadie more pure magnesium? Show your working.

32

CWK What are ceramics and why are they useful? …………/………/…………………..


C2 3.6

Ceramics

I can list the properties

of ceramics.

I can explain ceramic

properties.

I can distinguish between

chemical and physical

properties of ceramics.

I can list some uses of

ceramics.

I can explain why

properties of ceramics

make them suitable for

their uses.

I can justify why possible

ceramics are identified

from data about material

properties.

A. A ceramic material is a

…………………………………….. They include

……………………………… silicates, metal

…………………. , metal carbides and metal

……………………………………….

Examples are ………………………….. and bricks.

B. Four properties of ceramics are:

1. …………………………………………………………..

……………………………………………………………..

2. …………………………………………………………..

……………………………………………………………..

3. …………………………………………………………..

……………………………………………………………..

4. …………………………………………………………..

……………………………………………………………..

Key words compound metal nitrides pottery oxides bricks hard brittle stiff solid strong insulators

33

C. List three uses of ceramics

1. …………………………………………………………..

……………………………………………………………..

2. …………………………………………………………..

……………………………………………………………..

3. …………………………………………………………..

……………………………………………………………..

Complete the paragraph

........................................................................................................

........................................................................................................

........................................................................................................

........................................................................................................

........................................................................................................

........................................................................................................

34

Comparing ceramic strength 1 Which three ceramics will you test?

1

2

3

List of apparatus available: eye protection, clamp stand, masses of various sizes

ceramic samples, for example, dinner plates, roof tiles

What method will you use?

How can you use the apparatus above to design an experiment that will test the strength of

different ceramics?

Hint: could you hang masses from the ceramics, or pile them on top of the ceramics?

Write a step-by-step set of instructions in the space below.

Make sure you are only changing the type of ceramic being tested each time you do the

investigation.

1

2

3

4

5

6

7

35

4 How will you stay safe during your practical?

Fill in the risk assessment table below. Include other ideas you may have in the table.

Risk Likelihood of this happening How can we minimise this risk?

example:

dropping heavy

masses

unlikely

Ensure that masses are carried

with two hands and keep masses on top of tables where possible.

broken ceramic

clamp stands toppling

Results

Complete the results table below. The final column has been left blank for you to write

down the results of what you will be measuring.

Ceramic Description

36

Questions

1 Give the name of the independent variable in your investigation.

2 Give the name of the dependent variable in your investigation.

3 Explain how your method keeps the investigation fair.

4 Suggest any problems there may be in keeping your investigation fair.

Extension

1 Investigations should be valid. This means that they should measure, or find out about, what

they were meant to. Explain how your investigation is valid in measuring the strength of the

ceramic material.

37

Prove it:



………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

38

CWK What are polymers and why are they useful? …………/………/…………………..

A. A polymer is a substance

with very long ……………………………….

A polymer has …………………………

Groups of ……………………………

repeated many ………………….

B. Give an example of a polymer and one of it uses.

Polymer ……………………………………

Use ………………………………………….


C2 3.7

Polymers

I can state the definition

of a polymer.

I can describe polymer

properties.

I can explain properties

of different polymers.

I can state some uses of

polymers.

I can explain how

polymer properties


their uses.

I can compare properties

of different polymers.

Key words molecules identical atoms groups wool jumpers cotton rubber polythene

39

c. Describe why low-density poly(ethane)

makes good carrier bags.

…………………………………………………………………………………

.

…………………………………………………………………………………

.

…………………………………………………………………………………

.

…………………………………………………………………………………

.

…………………………………………………………………………………

.

…………………………………………………………………………………

.

Complete the passage:

40

Ch

oo

se a

Q

41

42

Choosing suitable polymers

Setting the scene

Polymers are very long molecules made of identical repeating groups of atoms.

Different polymers contain different groups of atoms. The different groups give

polymers very different properties. This means polymers can be designed to have

properties that make them good for particular uses.

Aims


3 look at some information about different polymers

4 use this information to decide which jobs they can be used for.


5 interpret data to draw conclusions

6 make predictions using your scientific knowledge

7 present explanations of data.

Task

Look through the table below about six different polymers. Use this information to fill in the grid

underneath, deciding which polymer is the most suitable for the different uses, and explaining

your answer.

Polymer Strength

Does it

conduct electricity?

Does it absorb water/

moisture?

What happens

when the polymer is

heated?

Cost to make (£

per square

metre)

Does it decay?

A very weak no no nothing 0.01 no

B very strong no no nothing 7.50 no

C strong no no it shrinks 0.05 yes, after

1 year

D strong no yes it burns 3.50 no

E weak no no nothing 0.02 yes, after

6 months

F weak yes no nothing 10.00 no

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Use Suitable polymer Reason for choice

t-shirt or top for a

marathon runner

disposable drinks cup

buoy

(floating marker in

the sea)

computer circuit

components

carrier bag

cling film

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Questions

1 Describe the differences between a synthetic and a natural polymer.

2 Suggest which two polymers above may be considered environmentally friendly.

Explain your answer.

Extension

Molecules that join to form polymers are produced from crude oil. Using this

information and your knowledge of fossil fuels, state three advantages and

three disadvantages of using polymers. Explain your answer.



………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

CWK What are composites and why are they useful? …………/………/…………………..

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A. A composite material is a

………………………………………………… of different

materials. Each material has different

…………………………………………………….

An example of a composite material is

……………………………………………………..

B. Two material in carbon-fibre-reinforced

plastic are ……………………………………………….

and ……………………………………………………………….


C2 3.8 Composite

s

I can state some

properties of composite

materials.

I can describe

composite properties.

I can explain composite

properties.

I can state some uses of

composite materials.

I can explain why

composite properties


their uses.

I can suggest advantages

and disadvantages of

composite properties.

Key words mixture properties polymer carbon fibres glue-like density rust strong layers

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C. Name two material in glass-fibre-

reinforced aluminium.

1. …………………………………………………..

2. ……………………………………………………

Summary/Prove it

Underline the correct word and cross out

the incorrect word (use pencil first).

……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. …………………………………………………………………………………….

……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. …………………………………………………………………………………….

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……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. …………………………………………………………………………………….

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Concrete properties

Setting the scene

Nisha has been finding out about the strength of concrete. Depending on how it is made, its

strength can vary, which means it can be used for lots of different purposes. She made concrete

by mixing 100 g of cement with water and a mixture called aggregate. She used different

amounts of aggregate each time and then tested the strength of the concrete.

Aims


8 use Nisha’s results to discover what she has found out about the strength of

concrete.


9 present her data in an appropriate graph

10 interpret the data to identify patterns and draw conclusions

11 come up with some further questions from the results.

Task

Plot a suitable graph of Nisha’s results shown in the table and answer the questions below.

Amount of aggregate material added (g) Strength of concrete (N/mm2)

400 35

450 25

600 20

800 10

1000 7.5

Questions

1 Describe the pattern shown in the strength of concrete in Nisha’s results.

Use the data to explain your answer.

As more aggregate material is added to cement mix

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2 Reinforced concrete consists of steel bars with concrete around them. Using your knowledge of

composites, explain why reinforced concrete is preferable to normal concrete in the

construction of a new building.

Extension

1 Use your graph to suggest the strength of a concrete mixture that is made using 1200 g of

aggregate material. Show your working.

2 Identify whether cement or aggregate material is responsible for the strength of concrete using

your graph. Explain your answer.

3 Aggregate material can contain different amounts of sand and coarse or fine materials.

Different manufacturers will sell different compositions of aggregate material. This means they

may contain different amounts of sand or gravel, for example. Suggest a further investigation

Nisha may wish to carry out into the strength of concrete.

You must identify the independent, dependent, and at least two control variables.



………………………………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………

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Glossary

Key word Definition

carbon fibre A material made of thin tubes of carbon.

ceramic A compound such as a metal silicate or oxide that is hard,

strong, and has a high melting point.

composite A mixture of materials with properties that are a combination

of those of the materials in it.

displace A more reactive metal displaces – or pushes out – a less

reactive metal from its compound.

displacement reaction In a displacement reaction, a more reactive metal displaces

– or pushes out – a less reactive metal from its compound.

metal

Elements on the left of the stepped line of the Periodic Table.

Most elements are metals. They are good conductors of

energy and electricity.

natural polymer Polymers made by plants and animals, including wool,

cotton, and rubber.

ore A rock that you can extract a metal from.

polymer A substance made up of very long molecules.

reactive A substance is reactive if it reacts vigorously with substances

such as dilute acids and water.

reactivity series A list of metals in order of how vigorously they react.

state symbol

A state symbol gives the state of a substance in a chemical

equation. (s) means solid, (l) means liquid, (g) means gas,

and (aq) means dissolved in water.

synthetic polymer A substance made up of very long molecules that does not

occur naturally.

thermite reaction Reaction of aluminium with iron oxide to make aluminium

oxide and iron.

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