OCR Gateway GCSE Science Spring 2011 course guide

OCRgateway

GCSESciences

Matches the new 2011 OCR Gateway GCSE science specifications

2

This course caters for all abilities and covers your assessment needs.

OUP OCR Gateway GCSE Science A4 12pp Update 21.12.indd 1 22/12/10 10:59:04

2

GC

SE

Sci

ence

(B

1, B

2, C

1, C

2, P

1, P

2)G

CS

E A

dd

itio

na

l S

cien

ce

(B3,

B4,

C3,

C4,

P3,

P4)

GC

SE

Sep

ara

te S

cien

ces

(B5,

B6,

C5,

C6,

P5,

P6)

Student Book Resources and Planning Pack

Resources and Planning OxBox CD-ROM

Exam Preparation and Assessment OxBox CD-ROM

Revision Guide Online Homework




GCSE Biology (B1–B6) GCSE Chemistry (C1–C6) GCSE Physics (P1–P6)

Student Book

Resources and Planning Pack

Exam Preparation and

Assessment OxBox CD-ROM


Resources and Planning OxBox

CD-ROM

Student Book






CD-ROM

Student Book






CD-ROM

Course structureOCR Gateway GCSE Science

wwwwwwwww

www

www

www




Revision Guide Online HomeworkExam Preparation and Assessment OxBox CD-ROM

GCSE Additional Applied Science

Entry Level Science (First teaching September 2012)

Student Book Workbook Resources and Planning iPack OxBox


Revision GuideResources and Planning Pack

Student Book Resources and Planning iPack OxBox


The Entry Level course is designed to meet the needs of students at KS4 for whom GCSE-level courses are not realistic or appropriate. It can also support the teaching of lower attaining candidates in GCSE classes.


Our resources for OCR Gateway GCSE Science have been specifically developed for the needs of real students and teachers. We’ve created a course that builds on the features of current resources that teachers like, whilst incorporating more assessment support and extra help with delivery. Our simple and clear approach will help you implement the new specifications with ease.

Why choose this course?

• Endorsed by OCR for use with the OCR GCSE Science B Gateway specification, these resources provide a simple and clear approach to help you implement the new specifications with ease

• It’s accessible and contains clear, exam-tier matched differentiation – higher and foundation content is highlighted so all students are catered for in one book

• It’s packed with lots of tiered questions at the end of every spread and at the end of the chapters, so students can practise at the right level for them and improve

• It provides end of chapter revision checklists and visual summaries so students know what they need to learn and spot areas of weaknesses

• There’s help provided for students to progress – Upgrade shows students what they need to improve and achieve their full potential

• It includes support for extended writing questions and Controlled Assessment to help you and your students get to grips with the new styles of assessment

Order your OCR Gateway GCSE Science Evaluation PackOrder your OCR Gateway GCSE Science Evaluation Pack today. It contains a copy of the GCSE Science Student Book, the GCSE Additional Science Student Book, and the GCSE Biology Student Book, as well as teacher material and a demo CD-ROM of the digital resources. This will give you a clear overview of the resources and it’s available on 90 days’ free evaluation to give you plenty of time to try them out. Email [email protected] to order yours.

OCRgateway

The simple and clear approach to the new specifications

For the latest news and information on OCR Gateway GCSE Sciences, visit www.oxfordsecondary.co.uk/ocrgatewayscience

3

Online

GCSESciences

“These resources are the best I have seen. I can tell they have been written by real teachers” Elizabeth Smith, Haydock Sports College.


OCRgateway

GCSE Science GCSE Science gives you and your students:

• An emphasis on getting more involved in the learning process through a variety of interesting activities and experiences, identifying links to scientific ideas and their implications for society

• The opportunity to develop scientific explanations and theories

• Flexible assessments, which can be carried out at the end of the course or at times during the course when learners’ understanding is at its best

GCSE Science Student Book

FREE eBook at the back of every Student Book – with annotation tools

GCSESciences

4

Exam preparation pages provide exam-style questions with exam tips for summary and revision work

P2

Why study this module?Human activity is leading to changes in climates and we are rapidly using up our natural resources. Scientists are working on solutions to these problems. We consume vast amounts of electricity every day, to power our TVs, mobiles and computers. In the future, how will we generate enough to meet our needs? In this module you will learn about how electricity is generated, and the advantages and disadvantages of the different technologies, from large coal-fired power stations to small solar cells on calculators.

Our planet is in a delicate balance. In this module you will be introduced to the science behind global warming and the impact of humans on the environment. You will learn about Earth’s place in the Universe, where it fits into the Solar System, how humans have explored space, and about the threats posed by asteroid impact. Finally, you will study scientific ideas about the origin of the Universe, how these ideas have changed over time, and how our Sun will eventually expand and incinerate the Earth.

You should remember

All human activity has an impact on the environment.1 The law of conservation of energy states that energy 2 cannot be created or destroyed.

Electricity may be generated in different types of 3 power station.

The Earth is one of a number of planets in our Solar 4 System, all in orbit of the Sun.

The world’s largest power station is the Three Gorges Dam on the Yangtze River in China. The project has been in development since 1994. When it reaches full capacity it will be able to produce as much as 22 500 000 000 watts of power (22.5 gigawatts, GW). That’s enough electricity for every person in the UK and Australia to watch their own large plasma TV at the same time.

The world’s smallest ‘power station’ is a phytoplankton – a single-celled aquatic organism that converts sunlight into chemical energy to create living biomass.

Living for the future

OCR specification match

P2a 2.1 Electricity from the

Sun

P2a 2.2 Other ways to use

energy from the Sun

P2b 2.3 The dynamo effect,

AC, and generators

P2b

2.4 Generating and

distributing

electricity

P2b 2.5 Fossil fuels and

biomass

P2b 2.6 Nuclear power

P2c 2.7 Global warming

P2d 2.8 Power and paying

for electricity

P2e 2.9 Alpha, beta, and

gamma radiation

P2e 2.10 Uses of radioactivity

P2f 2.11 The Solar System

P2g 2.12 Asteroids, comets,

and the Moon

P2h 2.13 The Big Bang

P2h 2.14 The life cycle of

stars

P2h 2.15 Changing ideas on

the Universe

Module summary

OCR Upgrade

Engaging opening pages start the module by outlining what students should already be familiar with from previous science teaching, linking back to KS3 and building links between modules in GCSE


28 29B1: UNDERSTANDING OURSELVES

Learning objectives

After studying this topic, you should be able to:

give examples of different types of adrugs

compare legal and illegal drugs a

Drugs may be benefi cial or harmfulA drug is a chemical that alters the way your body or brain works. Drugs may alter your behaviour as well as altering your metabolism.

Benefi cial drugs are medicines like painkillers (morphine and codeine) and antibiotics. Some have to be prescribed by a doctor. This is because they may

have side effectsinterfere with another medicine the patient is takingbe harmful for a particular patient if they have another conditionbe harmful if taken too often.

Some drugs are legal and used for recreation. These include caffeine, nicotine in tobacco, and alcohol.

Some athletes use performance-enhancing drugs like anabolic steroids. These can have harmful side effects. It may be unethical to use them as it gives some athletes an unfair advantage. The athletes may also suffer side effects from taking the anabolic steroids.

Properties of drugsBecause all drugs alter your body chemistry, your body may become tolerant to them. You may need to increase the dose to get the same effects.

Eventually your body may not work properly without the drug. Then you are addicted. Heroin and cocaine are very addictive.

If you stop taking the drug you get withdrawal symptoms. Depending on the drug, these can include

RehabilitationPeople who want to ‘kick the habit’ need rehabilitation. They may go into a hospital or special clinic. After not taking the drug for a few days, withdrawal symptoms fade and they feel better. They can cope without the drug. The staff in the clinic help and support the patients. They also prevent them taking the drug.

0AB1 8: Drugs

Key words

drug, tolerant, addiction, withdrawal symptoms, rehabilitation

Did you know...?

Some animals self-medicate. They eat certain leaves that they do not normally eat, to treat parasitic infections.

Field of opium poppies in Dorset. Opium is 5obtained from the seed heads of this poppy. Opium contains morphine and codeine. Opium can also be refi ned to make the illegal drug heroin.

OCRExam tip

Do not say that because something ais made from natural substances it is good for you. Many strong poisons come from plants.

A Name three drugs that can be obtained from opium poppies.

B Explain the following terms: drug; tolerance; addiction; withdrawal; rehabilitation.

C Why do you need to have a prescription from a doctor for certain drugs, like strong painkillers?

1 Name two types of class B drugs.

L

2 Why do you think new drugs have to be tested before they are licensed for use as medicines?

3 What are hallucinogens?

S

4 Explain how (a) depressants (b) stimulants work.

H

Questions

How depressants and stimulants workDepressants reduce activity at synapses. They bind to the receptor molecules on the next neurone and block transmission of the nerve impulse. Stimulants, on the other hand, cause more transmitter substance to cross the synapse.

Types of drug

Type of drug Example(s) Effects on your body and mind

depressants alcohol, solvents, temazepam

slow down brain and nerve activity

painkillers aspirin, paracetamol block nerve impulses

stimulants nicotine, caffeine, ecstasy

increase brain activity and counteract depression

performance enhancers

anabolic steroids increase muscle development

hallucinogens cannabis and LSD distort what you see/hear

Illegal drugsSome people use illegal drugs for recreation. Some drugs are more harmful than others. The Government has introduced the Misuse of Drugs Act. This divides drugs into categories.

Class Examples Penalties for possession

Penalties for dealing

A most dangerous, heaviest penalties

cocaine, heroin, LSD, mescalin, ecstasy, some types of cannabis

up to 7 years in prison, unlimited fi ne

up to life imprisonment, unlimited fi ne

B amphetamines, cannabis, strong codeine, ritalin, barbiturates, mephedrone



C least dangerous, lightest penalties

temazepam, anabolic steroids



Testing drugsNew drugs have to be rigorously tested before being licensed. They are tested on laboratory animals and human tissue to see if they are toxic. Then they are trialled on human volunteers.

90 91C1: CARBON CHEMISTRY

Learning objectives


explain what fossil fuels are adescribe how crude oil is aseparated into fractions

describe the main fractions aobtained from crude oil

explain why crude oil can be aseparated by fractional distillation

0AC1 1: Making crude oil useful

The fossil fuelsCrude oil is a fossil fuel. It was formed from the remains of living things that lived in the sea millions of years ago. These became buried deep in the seabed after they died. Chemical reactions happened that eventually turned them into crude oil.

Crude oil is a non-renewable resource. We are using it up much faster than more can form. Coal and natural gas are also fossil fuels and non-renewable resources. All the fossil fuels are fi nite resources. They will run out one day if we continue to use them.

The fractionating column is hot at the bottom and gradually gets colder towards the top. The vapours cool as they rise through the column. They condense to form a liquid when they reach a part that is cold enough. The liquid falls into a tray and is piped out of the column.

Hydrocarbons with the highest boiling points leave at the bottom of the column.Hydrocarbons with the lowest boiling points reach the top without cooling enough to condense, leaving as gases.

The substances leaving the column are called fractions because they are just a part of the crude oil. Each fraction contains hydrocarbons with similar boiling points. Different fractions have different uses, depending on their properties.

Intermolecular forcesThe atoms in hydrocarbon molecules are joined to each other by covalent bonds. These are much stronger than the intermolecular forces that attract hydrocarbon molecules towards each other. Intermolecular forces are broken when crude oil is boiled, rather than covalent bonds. This causes the hydrocarbon molecules to separate from each other, forming a vapour.

The larger the hydrocarbon molecules, the stronger the intermolecular forces, and the higher the hydrocarbon’s boiling point. The hydrocarbons with the smallest molecules are gases and those with the largest molecules are solids.

Crude oil is a thick liquid 5

Key words

crude oil, fossil fuel, non-renewable resource, fi nite resource, fractional distillation, fraction

LPG

petrol

paraffin

diesel

heatingoil

bitumen

fuel oil

crude oilvapour

350° C

25° C

decreasingtemperature

The different fractions from a fractionating 5column. LPG contains propane and butane gases.

Oil refi neries run continuously 5

Separating crude oilCrude oil is a mixture of many different compounds called hydrocarbons. The hydrocarbons in crude oil are separated from each other by fractional distillation. This happens at an oil refi nery in a tower called a fractionating column. Fractional distillation works because different hydrocarbons have different boiling points.

OCRExam tip

Remember that crude oil vapours amust be cooled and condensed so they can leave the fractionating column as a liquid.

A Name three fossil fuels.

B Explain why the fossil fuels are non-renewable resources.

1 What property of hydrocarbons lets fractional distillation of crude oil work?

2 State the names of three fractions from crude oil. Include a solid, a liquid, and a gas.

L

3 Describe how fractional distillation works.

4 Where does the fraction with the lowest boiling point leave the fractionating column? Name two hydrocarbons that this fraction contains.

S

5 Explain, in terms of intermolecular forces, why crude oil can be separated by fractional distillation. H

Questions

The crude oil is heated. Its vapours are piped into the bottom of the fractionating column, which has a temperature gradient.




Science summary pages provide checklists and visual summaries as a starting point for revision

5

A bright and modern page layout and structure, specially designed to engage and enthuse all your students while making the science as accessible as possible

Questions are differentiated by level of difficulty matched to the specification to cater for higher and foundation students in one book

Specification-linked learning objectives written in student-friendly language encourage your students to understand what is expected of them and monitor their own progress

Higher tier is highlighted on the page so all students understand what is required, allowing you to differentiate your teaching using only one book


26

Learning objectives


describe how to measure the aenergy transferred when foods and fuels burn

Behind the labelWhich do you prefer – crisps or cashew nuts? Which provide more energy?

0AC3 12: Measuring food and fuel energy

needle

wooden handle

heat resistant mat

hold thehandle here

clamp

test tube

water, 10 g

burning crisp

Measuring the energy in food 5

Food labels tell us how much energy foods provide. Eating 100 g of cashew nuts provides 2410 kJ of energy, and 100 g of crisps provides 2207 kJ.

Of course, energy values are not the full story. Cashew nuts and crisps provide similar amounts of energy, but the nuts are more nutritious.

How do food companies know what numbers to write on the labels? Today, they use data tables to work out the energy values of processed foods. Before these data were available, scientists compared food energy values by using burning foods to heat water. The energy transferred on burning is similar to that available to the person eating the food.

Measuring food energyFreya pours 100 g of water into a metal container. She measures its temperature. She heats the water with a burning crisp. She measures the temperature again.

Here is a summary of Freya’s results.

Mass of crisp (g) 1

Increase in water temperature (°C) 40

NutritionTypical values Per 30 g serving Per 100 gEnergy

ProteinCarbohydrate of which sugarsFat of which saturatesFibreSodium

725 kJ175 kcal

5.7 g5.3 g1.7 g

14.5 g2.7 g2.7 g0.0 g

2410 kJ585 kcal

19.0 g17.8 g5.8 g

48.2 g8.9 g8.9 gtrace

Calories175

Fat14.5 g

Saturates2.7 g

Salt0.0 g

Sugars1.7 g

Per 30 g servingPer 34.5 g pack Per 100 g

761 kJ 163 kcal

2.0 g

17.1 g 0.1 g

11.8 g 0.9 g 0.6 g 0.8 g

1.4 g

0.21 g

0.53 g

2207 kJ 529 kcal

5.9 g

49.7 g 0.4 g

34.2 g 2.5 g 27.9 g 2.2 g

4.2 g

0.60 g

1.17 g

TYPICAL NUTRITIONAL VALUES

Energy

Protein

Carbohydrateof which sugars

Fatof which saturates

of which mono-unsaturatesof which polyunsaturates

Fibre

Sodium*

*Equivalent as salt

A A joule is the unit of energy. Give the number of joules in one kilojoule, 1 kJ.

B Which stores more energy – 100 g of crisps or 100 g of cashews?

05 738 AQA Chemistry U3P1.indd 26 9/11/10 15:45:56

27CHEMISTRY C3 (PART 1)

Freya uses an equation to calculate the heat energy, Q, transferred to the water:

Q = mcΔTm is the mass of water, in grams.c is the specifi c heat capacity of the water. It is the energy needed to make 1 g of water 1 °C hotter. Its value is 4.2 J/g °C.ΔT is the temperature change of the water, in °C.

So for Freya’s experiment, the heat, Q, transferred to 100 g of water by 1 g of crisps:

= 100 g × 4.2 J/g °C × 40 °C= 16 800 J= 16.8 kJ

This gives a value of –1680 kJ for burning 100 g of crisps. The negative sign shows that the burning reaction is exothermic. It transfers energy to the surroundings. In other words, it gives out energy.

Freya’s value is different from that on the crisp packet. There are two reasons for this:

Not all the heat from the burning crisp was transferred to the water – some was transferred to the surroundings and the apparatus.Some of the energy in crisps – that in the fi bre – cannot be absorbed by the body. This energy is not included in the energy value on the crisp packet.

Comparing fuelsYou can use a similar experiment to compare the heat produced by burning fuels. The diagram shows how.

Key words

joule, kilojoule, specifi c heat capacity

spirit burner

water

clamp

clamp

thermometer

fuel, for example butan-1-ol

Measuring the energy in a fuel 3

1 Give the symbol for the scientifi c unit of energy.

S

2 Eva burns 1 g of butan-1-ol fuel in the apparatus shown. It makes 100 g of water 55 °C hotter. Calculate the amount of heat energy transferred to the water from the butan-1-ol. The specifi c heat capacity of water is 4.2 J/g °C.

M

3 Eva checks her result in a data book. This states that burning 1 g of butan-1-ol releases 36 122 J of heat energy. Suggest why Eva’s value is different from that in the data book.

H

Questions

Did you know...?

100 g of crisps provides 10 times more energy than an apple of the same mass, but the apple is much richer in vitamins and minerals.

AQAExam tip

Take care with units, and note awhether energy values are given in joules (J) or kilojoules (kJ). You may even be given energy data in calories.

05 738 AQA Chemistry U3P1.indd 27 9/11/10 15:45:57

OCRgateway

GCSE Additional Science GCSE Additional Science places a greater emphasis on explaining, theorising and modelling science. It provides a natural progression from GCSE Science and gives students a solid foundation to move on to study separate AS and A Level Sciences.

GCSE Additional Science Student Book

To find out more about Controlled Assessment visit www.gcse-science.com

Online

6

GCSESciences

Learning objectives

After studying this topic, you should be able to recall that enzymes:

are proteins that catalyse chemical areactions in living cells

have high specifi city for their asubstrates

work best at particular atemperatures and pH

Enzymes are catalystsEnzymes are catalysts because they speed up chemical reactions.

Most of these reactions, such asphotosynthesisrespirationprotein synthesis

take place inside living cells.

Enzymes can be used to catalyse the same type of reaction many times. This is like using one type of screwdriver to screw in many of the same type of screw, one at a time.

The shape of an enzyme is vital for its functionEnzymes, like all proteins, are folded into a particular shape. The shape of one particular area of the enzyme molecule, called the active site, is very important.

The substrate molecules fi t into the active site. This brings them together so they can form a bond.This makes a bigger molecule.

In some cases (as shown below right):a big substrate molecule fi ts into the active sitea bond breakstwo smaller product molecules are made.

0AB3 4: Enzymes

Key words

enzyme, catalyst, substrate, specifi c, optimum, denatured

The large substrate molecule fi ts into the 5enzyme’s active site. A bond breaks and two product molecules are formed.

large substratemolecule

active site

enzymemolecule

substratemoleculefits intothe enzyme’sactive site

free enzyme, able to catalyseanother reaction the same as this

bond insubstratemoleculebreaks

1

2

3

two smallerproduct

molecules

bond

enzyme-substratecomplex

The lock and key hypothesis is a hypothesis about how enzymes work. The 5two substrate molecules fi t side by side into the enzyme’s active site. A bond forms between them and one large product molecule is formed.

A What is a catalyst?

B Name three types of chemical reaction that enzymes speed up in living organisms.

96

03 725 GATEWAY Biology Mod B3.indd 96 1/12/10 13:49:38

Enzymes have specifi city for their substrate

Only one particular type of substrate molecule can fi t into an enzyme’s active site. This is like the way only one type of key will fi t into a particular lock. This means each enzyme is specifi c for its substrate molecules.

E How is each enzyme specifi c for a particular substrate?

Did you know...?

Many enzymes in the body could work more quickly at temperatures above 37 °C. However, if we kept our bodies hotter than this, many of our other proteins would be damaged. At 37 °C our chemical reactions go on fast enough to sustain life. But some bacteria can live in very hot places, and their enzymes work well at 100 °C.

C What are enzymes made of ?

D Why is the shape of the active site of an enzyme important?

97B3: LIVING AND GROWING

1 State two conditions that enzymes need to work best.

L

2 Describe how increasing the temperature from 10 °C to 25 °C makes the rate of an reaction increase.

3 Describe how if the temperature increased to 60 °C, the rate of the reaction would slow down and eventually stop.

S

4 As well as having enzymes inside your cells, you also have them in your blood. Your blood pH needs to be kept very close to 7.2. Why do you think this is?

H

Questions

What makes enzymes work best?Each enzyme works best at

a particular temperature, known as its optimum (best) temperatureits optimum pH.

Low temperaturesThe enzyme and substrate molecules have less energy. They do not move very fast so they do not collide (bump into each other) very often. The rate of reaction is low.

High temperaturesAs the temperature increases, the enzyme and substrate molecules move more quickly and collide more often. This gives a faster rate of reaction.

However, if the temperature becomes too high then: The shape of the enzyme’s active site changes.The substrate molecule cannot fi t into the active site.The rate of reaction slows and eventually stops.

When the shape of the enzyme has changed in this way, it cannot go back to its original shape. The change is irreversible. The enzyme is denatured.

pHEach type of enzyme works at an optimum pH. If the pH changes very much then:

The shape of the active site changes. The substrate molecules cannot fi t into it.The enzyme has been denatured.

03 725 GATEWAY Biology Mod B3.indd 97 1/12/10 13:49:38

Worked examples focus on equations needed for the exams showing students how to work through problems in preparation for assessment and providing a reference point for revision

Questions at specification-matched levels are provided throughout to help students pause and reflect on what has been learnt, helping you to reinforce content throughout the course



GCSE Separate Sciences GCSE Biology, Chemistry and Physics provide a firm foundation for students who want to go on to study separate sciences at A Level.

It’s easy to deliver the GCSE Separate Science option with two flexible routes. Choose either to buy GCSE Biology, GCSE Chemistry and GCSE Physics which each contain six modules or you can choose to use the Separate Science Student Book that covers just modules B5, C5, P5 and B6, C6, P6 alongside your existing resources for GCSE Science and GCSE Additional Science.

Are you also teaching GCSE Additional Applied Science?We also publish resources for GCSE Additional Applied Science. This specification is freestanding so may be used with the OCR Gateway GCSE Science specifications. Visit www.oxfordsecondary.co.uk/additionalappliedscience for more information.

GCSE Chemistry Student Book

7

28

Learning objectives


name some strong and weak acids adescribe acids in terms of pH, ahydrogen ion concentration, and electrical conductivity

explain the differences between astrong and weak acids

Eating acidVinegar contains ethanoic acid. This gives vinegar the pleasant, sharp taste that makes it a popular addition to fi sh and chips. While you can safely consume vinegar, it would be very unwise to swallow hydrochloric acid. This is because ethanoic acid is a weak acid, but hydrochloric acid is a strong

acid. Nitric acid and sulfuric acid are strong acids, too.

Differences in pHStrong acids and weak acids have different pH values, even if they are at the same concentration. A strong acid will have a lower pH than a weak acid of the same concentration. Its solution will be more strongly acidic. The differences in pH can be measured using universal indicator and a pH colour chart, or using a pH meter. The reason for these differences is due to hydrogen ions produced by the acids.

Acids ionise in water to produce hydrogen ions, H+. Strong acids such as hydrochloric acid completely ionise in solution. Weak acids such as ethanoic acid only partially ionise in water. Many of their molecules do not release hydrogen ions. Unlike the reaction for strong acids, the reaction is reversible, and an equilibrium mixture is produced.

Acid strength and concentrationThe concentration of an acid is a measure of the number of moles of acid in 1 dm3. The higher the concentration, the more moles of acid are dissolved in the same volume of water. The strength of an acid is a measure of how ionised the acid is in water. The stronger the acid, the more ionised it is. Hydrochloric acid is completely ionised in water, whereas ethanoic acid is only partially ionised in water:

HCl H+ + Cl– (hydrochloric acid)CH3COOH CH3COO– + H+ (ethanoic acid)

So, for a given concentration of acid, the concentration of hydrogen ions is greater in hydrochloric acid than it is in ethanoic acid. This is why the pH of a strong acid is much lower than the pH of a weak acid at the same concentration.

0AC5 13: Strong and weak acids

Vinegar contains ethanoic acid, a weak acid 5

A At the same concentration, acid A has a pH of 2 and acid B has a pH of 5. Which one is the weak acid, and why?

Key words

weak acid, strong acid, hydrogen ions, ionise, electrode, electrolysis, electrical conductivity

05 726 OCR Chemistry Mod C5.indd 28 12/11/10 14:40:24

29C5: QUANTITATIVE ANALYSIS

Electrolysis of acidsSolutions containing ions conduct electricity because the ions are free to move. They carry charge from one electrode to the other. Acids in solution contain hydrogen ions and other ions, so they conduct electricity. Hydrogen gas is made at the negative electrode during the electrolysis of either hydrochloric acid or ethanoic acid. This is because the positively charged hydrogen ions are attracted to the negatively charged electrode, where they gain electrons and become hydrogen gas:

2H+ + 2e– H2

OCRExam tip

The lower the pH, the more astrongly acidic a solution is.

Make sure you understand the adifference between strength and concentration in acids.

1 Which will have the lower pH, 0.1 mol/dm3 ethanoic acid or 0.1 mol/dm3 hydrochloric acid?

2 Which will have the lower electrical conductivity, 0.1 mol/dm3 ethanoic acid or 0.1 mol/dm3 hydrochloric acid?

L

3 In terms of ions and ionisation, explain why ethanoic acid is a weak acid but hydrochloric acid is a strong acid.

4 Explain why hydrogen is produced at the negative electrode during the electrolysis of acids.

S

5 Explain the difference between acid strength and acid concentration. Include balanced equations referring to ethanoic acid and hydrochloric acid.

H

Questions

However, although the electrolysis of both strong and weak acids produces hydrogen gas, there is a difference in the electrical conductivity of the acids. It is more ‘diffi cult’ for current to pass through a weak acid than it is through a strong acid at the same concentration. For a given potential difference or voltage, the current will be lower through the weak acid. The electrical conductivity of ethanoic acid is lower than it is for hydrochloric acid at the same concentration, because ethanoic acid solution contains fewer hydrogen ions.

B What gas is produced at the negative electrode during the electrolysis of acids?

More on conductivityEthanoic acid is less conductive than hydrochloric acid at the same concentration because it is a weak acid, whereas hydrochloric acid is a strong acid. There is a lower concentration of hydrogen ions to carry the charge through ethanoic acid than there is in hydrochloric acid.

The ammeter on 3the left is measuring the current through ethanoic acid, and the one on the right is measuring the current through hydrochloric acid at the same concentration

05 726 OCR Chemistry Mod C5.indd 29 12/11/10 14:40:25

Key words needed to understand the specification are highlighted to help you reinforce important knowledge

Separate Sciences optionsRoute 1 Route 2

GCSE Additional Science

GCSE Separate Science

GCSE Science GCSE Chemistry GCSE PhysicsGCSE Biology

Exam tips help your students prepare for their exams and reach their full potential


OCRgatewayOxBox CD-ROMs The OxBox is a flexible, time-saving digital resource that contains what you need to create lively and engaging lessons and fully prepare your students for their exams:

• Packed full of classroom resources, lesson planning and assessment - there is a Resources and Planning OxBox CD-ROM and a separate Assessment and Exam Preparation OxBox CD-ROM for each specification

• Content is customizable – adapt it to suit your needs and add your own resources directly into your lessons

• Incredibly easy to use with simple navigation

• A network licence is included in the price and it also comes with a FREE VLE disk

• There are no hidden subscription fees – just a single, one-off payment

GCSE Science Resources and Planning OxBox CD-ROM

Choose from a variety of resources (including videos, interactive activities, PowerPoint presentations, and artwork) to create lively and motivating lessons to engage your students

Create and add in your own resources, thus forming a bank which all teachers in your department can access and share

Most resources are customizable; adapt the resources and activities to suit your own students’ needs

Content is customizable

8

GCSESciences

Contains an eBook

version of the

Student Book –

with annotation

tools

View an online demo of the OxBox at www.oxfordsecondary.co.uk/ocrgatewayscience



GCSE Science Resources and Planning OxBox CD-ROM

The course overview and lesson plans familiarize you with the objectives and contents of each unit, allowing you to map out the term’s work quickly and easily

OxBox supports Controlled Assessment and includes sample tasks and guidance on preparation time

Supports the new Controlled Assessment

Easy to add in your own resources

GCSE Science Exam Preparation and Assessment

OxBox CD-ROM

The Launch Player function allows you to launch resources from the plan, without your students seeing the plan while you run the lesson

You can adapt planning material or create your own, attaching the resources you want to use in your lesson

9

The diagnostic tool helps with progression from Key Stage 3 and through the GCSE course to A Level

Exam answer tips show students typical exam-style questions, give explanations of what examiners are looking for, and show what a student needs to do in order to gain marks and progress through three grade bands


© Oxford University Press 2010 This document may have been altered from the original.

1

Time: 1 hour

APP ref(s): AF1 level 7, AF2 level 6

Book links: Page 14

Specification links: B1a

Lesson objectives:

• Recall that blood in arteries is under pressure and that this can be measured.

• Describe the factors that affect blood pressure.

• Explain the difference between fitness and health.

• Explain the link between saturated fat, cholesterol, and heart disease.

Previous knowledge required:

KS3:

• How diet affects health

• Human circulatory system

Key words:

Disease, systolic pressure, diastolic pressure, thrombosis

Fundamental Scientific Processes:

• Suggest ways of limiting risks, and recognise the benefits of

activities that have a known risk (L, S, H).

• Choose the most appropriate format for presenting data, and

process data using mathematical techniques such as statistical

methods or calculating the gradients of graphs (L, S, H).

• Determine the level of confidence for a conclusion based on the

identification of a qualitative relationship between variables and

describe how further predictions can lead to more evidence

being obtained (L).

Starting off (10 minutes) Resources required

1 Show Presentation (IB1.1.1) Lesson objectives. A Presentation with the images from the Student book (IB1.1.2) is

also available.

2 Discuss the terms ‘fitness’ and ‘health’. What do the students think these terms mean?

3 Summarise their responses. Students answer questions A–B on page 14 of the Student book.

Presentations IB1.1.1,

IB1.1.2

Student book

Lesson plan B1.1 Fitness and health

1 Practical activities have been checked for health and safety advice by CLEAPSS.

All users will need to review the risk assessment information and may need to adapt it to local circumstances.


Getting started

Working in pairs, you are going to make your own version of a seismometer. This

is a piece of equipment that detects and measures the strength of earthquakes.

Investigating

1 Collect your apparatus – a retort stand (with clamp and boss), a 1 kg mass,

some string, and a felt-tip pen.

2 Use the equipment to make your seismometer, as shown below:

You will need to Sellotape the pen to the side of the 1 kg mass so that it is

pointing down, with the tip just touching the surface of the paper.

Equipment required per group:

Retort stand

String (strong enough to support 1 kg)

Felt-tip pen

1 kg mass (with hanger)

Sellotape

Four pieces of graph paper

Health and Safety notes:

• Take care with the use of heavy masses.

Student activity AP1.16.1

Lesson reference: P1.16 Seismic waves

Book links: Page 196

Specification links: P1h

Make your own seismometer

1 Practical activities have been checked for health and safety advice by CLEAPSS.

All users will need to review the risk assessment information and may need to adapt it to local circumstances.


Main ideas

Student activity AC2.8.1 Materials for cars

• Students may be familiar with the typical properties of different materials but may find it difficult

to link the properties to particular uses.

• Emphasise that a material will be chosen for several reasons, which may include cost and

appearance, not just its performance. For example, low-end vehicles will have artificial fibre

seats but high-end vehicles may have leather seats.

• Consider the balance between using aluminium or steel for car bodies. It is noteworthy that

despite the apparent advantages of aluminium over steel, most car bodies are steel.

• When discussing recycling, mention that many car parts are sold for re-use, even if the car as a

whole may need to be scrapped (for example, after an accident).

• Discuss the implications for the EU directive that specifies the percentage in terms of mass, not

volume or number of parts. What part of the car counts for the greatest mass?

Answers

Student activity AC2.8.1 Materials for cars

A Example table:

Car part Properties needed Material(s)

Body Hard, strong, does not rust Aluminium, steel (if protected)

Cable for electrics Conducts electricity, can be made

into wires

Copper, aluminium

Carpet Soft and hardwearing Fibres

Dashboard Can be moulded into shape and

coloured

Plastics

Engine Strong and heat-resistant Aluminium, steel

Seat covers Soft and hardwearing, insulators Fibres

Windows Transparent Glass, plastic

Fundamental Scientific Processes:

Science in Society

• Identify some arguments for and against a scientific or technological development, in terms of

its impact on different groups of people or the environment (L,S,H).

Institutions and Social Practices

• Distinguish between claims/opinions and scientific evidence in sources (L,S,H).

Teacher and technician notes TC2.8

Lesson reference: C2.8 Making cars

Book links: Page 142

Specification links: C2d

Making cars

GCSE Science Lesson Plan

OCRgateway

Resources and Planning Packs The Resources and Planning Packs provide you with the support you need to teach the new 2011 specifications. They contain a wealth of support including lesson plans covering the whole course, homework and cover lessons, activity sheets and teacher guidance.

Content perfectly complements the Students’ Books so you can get the most out of the course

OxBox activities are clearly referenced, throughout making it easier for you to integrate your electronic resources

Step-by-step guidance every step of the way

Revision Guides Revision Guides are available for GCSE Science, GCSE Additional Science, GCSE Biology, GCSE Chemistry, GCSE Physics and one for B5 and B6, C5 and C6, and P5 and P6. These provide the best exam preparation available.

GCSE Science Activity Worksheet GCSE Science Teacher and Technician Notes

10

GCSESciences

Material is matched to the new 2011 specifications to help you with the transition



11

Interested in finding out more about

Online Homework? Online Homework is available for GCSE Science, GCSE Additional Science, GCSE Biology, GCSE

Chemistry, GCSE Physics, and for top up to Separate Sciences.

The subscription costs £100 per year and is updated on a regular

basis. Simply email [email protected]

or call 01536 452620. Make sure you quote the

ISBN and provide your valid email address.GCSE Science

Online Homework – Homework Task

GCSE Science Online Homework –

Menu Screen

Online Homework OCR Gateway GCSE Science Online Homework covers your students’ home learning needs. All activities are online so your students can access and complete their work easily at home.

Time-saving and straightforward to use, homework completed by students is automatically marked so that you can instantly see results

It’s simple to assign homework to student groups of any size – all done at the click of a button

Setting up groups and teacher users is straightforward and fast

It’s easy to see which students have completed their homework and when

Makes homework an interactive experience, allowing students to complete their work multiple times and receive feedback, so they can learn as they go

Activities are engaging to keep your students motivated


OCRgatewayOrdering details

1tel 01536452620 email [email protected] 01865313472 web www.oxfordsecondary.co.uk/ocrgatewayscience K3

7411

Title ISBN Publication Date PriceEvaluation Pack 978 019 912808 2 Spring 2011 £40.00

GCSE ScienceStudent Book 978 019 913552 3 Spring 2011 £16.99

Resources and Planning Pack 978 019 913555 4 Spring 2011 £195.00

Resources and Planning OxBox CD-ROM 978 019 913556 1 Spring 2011 £499.00 +VAT

Exam Preparation and Assessment OxBox CD-ROM 978 019 913557 8 Spring 2011 £275.00 +VAT

Revision Guide 978 019 913553 0 Spring 2011 £9.99

Online Homework 978 019 912844 0 Summer 2011 £100.00 +VAT

GCSE Additional Science Student Book 978 019 913558 5 Spring 2011 £16.99






GCSE Separate SciencesStudent Book 978 019 913563 9 Spring 2011 £16.99






GCSE BiologyStudent Book 978 019 913568 4 Spring 2011 £16.99






GCSE ChemistryStudent Book 978 019 913573 8 Spring 2011 £16.99






GCSE PhysicsStudent Book 978 019 913578 3 Spring 2011 £16.99






All prices and publication dates are subject to change.

Don’t forget to order your Evaluation Pack The OCR Gateway GCSE Sciences Evaluation Pack shows you how this course matches the new 2011 specifications. It’s available on 90 days’ free evaluation to give you plenty of time to look at the resources.

GCSESciences


Date post:	23-Nov-2014
Category:	Documents
Upload:	oxford-university-press-children-and-schools
View:	117 times
Download:	0 times

OCR Gateway GCSE Science Spring 2011 course guide

Documents