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SCIENCE YEAR 8 REVISION GUIDE—CHEMISTRY SECTION

Science Department

This Revision Guide will be generated as the year progresses. Each topic is

covered with both ‘key fact’ sheets, a question sheet and a suggested revision

method.

The question sheet is designed to test your revision of the key facts and see if

the information has sunk in. Just answering the questions is not an effective

revision method.

You will be given a set of sheets for each topic as you cover them in lessons.

The revision sheets will help you to revise for the end of unit test and your

school entrance exams at the end of year 8.

You will be given one hard copy to store in this folder but replacements can

be found online in the Student and Parent Portal section of the school

website. You are allowed to print as many copies as you like for your own

use.

We hope that they will be useful.

Good Luck

The Science Department

Element = Substance consisting of one type of atom

Compound = Substance consisting of two or more different elements chemically combined

Mixture = Substance containing two or more elements or compounds that

have not been chemically joined.

Molecule = A groups of atoms chemically joined e.g. water H2O, oxygen O2

The Atom

Particle Theory As particles are heated they gain kinetic energy. As they are cooled they lose kinetic energy.

Elements Elements form the periodic table.

Metal Oxides are BASIC and SOLID

For example magnesium + oxygen magnesium oxide

Non-metal Oxides are ACIDIC and GASES

For example carbon + oxygen carbon dioxide

Elements, Compounds and Mixtures

Consists of three different units. Electrons (negatively charge and

whizzing around the outside), Protons (Positively charged and in the

nucleus.) and Neutrons (no charge and in nucleus).

Atoms combine to form compounds.

Name Symbol

Hydrogen H

Carbon C

Sulphur S

Iron Fe

Copper Cu

Sodium Na

Oxygen O

Nitrogen N

Calcium Ca

Helium He

Magnesium Mg

Potassium K

Non-metals Metals

Compounds

Compounds are formed when two or more elements combine.

Compounds have different properties to the elements that combine to make them.

Naming Compounds

1. –ide = Two elements joined together e.g. Iron + Sulphur Iron Sulphide

2. –ate = More than two elements joined together with oxygen being one of them

e.g. Copper + Sulphur + Oxygen Copper Sulphate

Class practical: Iron + Sulphur Iron Sulphide

Look at the observations made during this reaction.

Chemical Symbols

Chemical symbols are used to represent compounds. The numbers relate to how many atoms there

are in the compound.

Water has two Hydrogen atoms

Conservation of mass – The mass of the reactants equals the mass of the products. For example,

Magnesium gets heavier when heated in air because it chemically combines with oxygen to form

Magnesium oxide (Mg MgO).

Mixtures

Mixtures are two elements or compounds that are together but not chemically joined.

Dissolving is a good way to form a mixture.

Mixtures can be easily separated (See separating substances section when complete)

You need to recognise this reaction. It shows that a new substance is formed.

Before reaction Iron is magnetic. Iron Sulphide is not

and therefore proves a new substance has been formed.

H2O and one Oxygen atom

Possible Revision Method—Summary Cards

Summary Cards contain the most important details of a topic. You should try to create

a summary of the information, including key words, concepts and diagrams.

Su

mm

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ixtures

Card

No

. __

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Questions

If you have revised the previous sheets effectively you should be able to answer the following

questions without difficulty.

1. What three particles combine to form an atom?

2. What is the name given to the negatively charged particle in an atom?

3. Define an element.

4. Define a compound.

5. Define a mixture.

6. Draw diagrams to represent the particles in each of the states of matter below.

7. Where do you find non-metals on the periodic table?

8. Copper + Oxygen ___________________

9. Copper + Sulphur + Oxygen ____________________

10. Iron + Sulphur ___________________

11. How can you tell that a reaction is occurring (or has occurred) between Iron + Sulphur in

the production of Iron Sulphide? Give two reasons

12. How many Carbon atoms are there in a molecule of Glucose?

C6H12O6

Solid Liquid Gas

For extra info or help with revision use the following pages in the KS3 CGP The Study Guide

Atoms and Elements pg. 35

Periodic Table pg. 36

Compounds pg. 37

Naming Compounds pg. 38

Mixtures pg. 39

Making and Testing Gases & Gases in the Air

Hydrogen

Making Hydrogen

METAL + ACID SALT + HYDROGEN

MASH

Testing for Hydrogen

Using a lit splint the hydrogen should ignite with a

squeaky pop.

Oxygen

Making Oxygen

Thermally decompose (heat) potassium permanganate

Testing for Oxygen

Using a glowing splint plunge into oxygen and it should relight.

Carbon Dioxide

Making Carbon Dioxide

METAL CARBONATE + ACID WATER + SALT + CARBON DIOXIDE

MCAWSCD

Testing for Carbon Dioxide

Bubble carbon dioxide through limewater. Limewater turns

milky white.

Collecting Gas over water

If a gas needs to be collected it should be done over water as shown in diagram be-

low. (Learn the diagram!)

Gases in the Air

Air is a mixture of gases

It consists of different quantities of a variety of different gases

To prove the percentage of oxygen you can use the set up shown below. Heat the copper

filings between the syringes to form copper oxide and remove oxygen from the air within the

syringes. The syringe should read 100ml at the beginning and 79ml at the end thus showing ox-

ygen is 21% of air.

HEAT

Gas Percentage of

Air

Nitrogen 78%

Oxygen 21%

Carbon Dioxide 0.03%

Argon and other

trace gases Trace amounts

Possible Revision Method—Review Cards (Flash Cards)

Review Cards pose questions with long answers or facts on the back.

Flash Cards can be used to learn key words or definitions

SC

IEN

CE

: Mak

ing an

d Te

sting G

ases

Questio

n

Answ

er(s)

Questions



1. How is Hydrogen made in a lab?

2. How do you test for Hydrogen?

3. How is Oxygen made in a lab?

4. Do you use a lit splint or glowing splint to test for oxygen?

5. What substance is used to test for carbon dioxide?

6. What change is seen in this substance if carbon dioxide is present?

7. Write the word equation for the production of carbon dioxide.

8. Write the word equation for the production of hydrogen.

9. Draw the diagram for the collection of gas over water.

10. Why does gas rise to the top of the test tube when being collected over water?

11. What is the percentage of Nitrogen in the atmosphere?

12. If 100cm3 of Air is passed over copper filings which are being heated. After several

minutes what will be the volume of air?

13. Why?

Fuels

Fuels react with oxygen to release energy. Most fuels contain hydrocarbons.

These are compounds of hydrogen and carbon only.

Complete Combustion: Complete combustion releases more energy than

incomplete combustion. It requires a plentiful supply

of air so that the elements in the fuel react fully with

oxygen.

The general equation for complete combustion is:

hydrocarbon + oxygen carbon dioxide + water

Incomplete Combustion:

Incomplete combustion occurs when the supply of air or oxygen is poor, resulting in carbon

monoxide being produced rather than carbon dioxide and producing some carbon (soot) which

has not be oxidised.

The general equation for incomplete combustion is:

hydrocarbon + oxygen carbon monoxide + water

or

Hydrocarbon + oxygen carbon + water

The Bunsen Burner

Air hole open

When the air

hole is open, air

is drawn into the

chimney, where

it mixes with the

natural gas. This

ensures complete

combustion.

Air hole closed

When the air hole is closed

the natural gas can only mix

with air at the mouth of the

chimney. Incomplete

combustion occurs as a

result. A yellow flame is

produced, which transfers

less heat energy than the

blue flame.

Questions

If you have revised the previous sheets effectively you should be able to answer the fol-

lowing questions without difficulty.

1. How can you test that carbon dioxide gas was produced?

2. What is a test to determine that water is present?

Acids, Alkalis and Neutralisation

Acids

Have a low pH

Have a sour taste (tartaric acid used in toxic waste sweets!!)

Contain Hydrogen and are used to make Hydrogen in reactions with metals.

Make Carbon Dioxide in reactions with carbonates.

Can react to produce salts – Hydrochloric Acid Chloride Salts, Nitric acid Nitrate

Salts, Sulphuric Acid Sulphate Salts etc.

Alkalis

Have a high pH

Soapy texture (often used in cleaning fluids)

Alkalis are soluble bases (bases which have dissolved)

All alkalis are bases but not all bases are alkalis.

Bases

Substances which can neutralise an acid.

When dissolved in water to form a solution are called alkalis

Usually metal oxides, hydroxides or carbonates e.g. Magnesium Oxide, Sodium

Hydroxide.

The pH Scale

Used to help identify the strength of an acid or base/alkali.

Universal Indicator is used to help show the pH by checking the colour

it turns against the colour chart.

If an acid is diluted its pH does not change significantly.

Neutralisation

When acids and alkalis are combined to form salts.

The salt contains the metal from the alkali and part of the acid molecule.

eg Sodium Hydroxide + Hydrochloric Acid Sodium Chloride + Water

The salt depends on the type of acid e.g. sulphuric acid forms

sulphate salts.

ACID + ALKALI SALT + WATER

The Reactions of Acids with Alkalis, Bases, Metal Carbonates and Metals

The Rules

Bases are metal oxides or metal hydroxides, e.g. iron oxide and calcium hydroxide.

Alkalis are bases which dissolve in water. They are always metal hydroxides, e.g.

potassium

hydroxide and sodium hydroxide.

Metals all conduct electricity. Lots of them have names ending in ‘-ium’ although

there are a few

non-metals which also end in ‘-ium’. They include metals with common names like

copper, lead and aluminium.

Metal Carbonates are all metals combined with carbonate groups, e.g. copper

carbonate, potassium carbonate and iron carbonate. They are also classified as bases

because they neutralise acids, but they react with acids in a different way to metal

oxides and metal hydroxides.

Acids all contain hydrogen. The three we need to know are hydrochloric acid,

sulphuric acid and nitric acid.

Hydrochloric acid reacts to form chloride salts

Sulphuric acid reacts to form sulphate salts

Nitric acid reacts to form nitrate salts.

The Rules II

Base + Acid Water + Salt (BAWS)

Acid + Alkali Water + Salt (AAWS)

Metal + Acid Salt + Hydrogen (MASH)

Metal Carbonate + Acid Water + Salt + Carbon Dioxide (MCAWSCD)

A salt is a metal sulphate, metal chloride or metal nitrate.

Hydrochloric acid makes chloride salts

Sulphuric acid makes sulphate salts

Nitric acid makes nitrate salts Phosphoric acid makes phosphate salts

Neutralisation Reactions

1. Sulphuric Acid + Copper oxide

2. Nitric Acid + Iron carbonate

3. Hydrochloric acid + sodium hydroxide

4. Sulphuric acid + Zinc

5. Acetic acid + aluminium

6. _____________ + ____________ lead nitrate + carbon dioxide + water

7. ______________ + Magnesium Magnesium chloride + _____________

8. Nitric acid + ____________ Calcium __________ + water

9. Zinc oxide + Nitric acid

10. Magnesium hydroxide + sulphuric acid

11. Copper + hydrochloric acid

Possible Revision Method—Review Cards (Flash Cards)

Review Cards pose questions with long answers or facts on the back.

Flash Cards can be used to learn key words or definitions

SC

IEN

CE

: Neutralisatio

n Salt N

ames

Questio

n

Answ

er(s)

Questions



1. Is an acid’s pH low or high?

2. What chemical element do all acids contain?

3. Name a household acid.

4. What chemical compound do acids always produce in the reactions you have learnt?

5. What acid produces chloride salts?

6. What acid produces sulphate salts?

7. What acid produces nitrate salts?

8. What is an alkali?

9. Is an alkali’s pH high or low?

10. Name a household alkali.

11. Give two examples of bases.

12. What is the pH scale used for?

13. How do you find the pH of a chemical? (include all detail!) [3 marks]

14. Does an acid’s pH change much if water is added to it?

15. What determines which salt is produced in a neutralisation reaction?


Acids and Alkalis pg. 52

Neutralisation Reactions pg. 53

Reaction of Metals with Acids pg. 55

Reaction of Oxides with Acids pg. 56

Particle and Kinetic Theory & Waters and Solutions

Particle and Kinetic Theory

Particle theory states that mass exists in particles

Kinetic theory revolves around the particles moving differently at different temperatures or

energy states.

Changes of state

Fixed shape

Fixed Volume

Particles Vibrate

Doesn’t flow

Shape of container

Fixed Volume

Particles move a

little more than

solid but still

touching

Flows

Shape of container

No Fixed Volume

Particles move

quickly

Flows

Water and Solutions The heating curve of water as shown on a graph. You must learn what the plateaus on the graph repre-

sent.

If you add salt or other minerals to water it lowers the freezing point (takes it below 0oC) and

raises the boiling point (takes it above 100oC)

This is why salt is put on roads to de-ice and in boiling water to cook pasta quicker.

Tests for Water

Hydrated = Contains water within the chemical structure

Anhydrous = Without water in the chemical structure

Anhydrous Copper Sulphate goes from white blue when water is added. It turns into

hydrated copper sulphate.

Anhydrous Cobalt Chloride goes from blue pink when water is added. It form hydrated cobalt

chloride.

Questions



1. Draw diagrams to represent the particles of solids, liquids and gases.

2. Using kinetic theory describe what happens when a solid melts?

3. Using particle theory explain what the particles of a gas are like?

4. Using kinetic theory explain what happens when a gas condenses

5. What is the energy transfer that occurs during melting?

6. What is the process called when a gas turns directly into a solid?

7. Describe, using the most scientific language possible, what happens when a bar of dairy

milk is left in the midday sun for an hour and then put in the fridge overnight.

8. Draw the heating curve graph for water and label each plateau appropriately.

9. What does the term hydrated mean?

10. Describe the colour changes when anhydrous copper sulphate is exposed to water?

11. Describe the colour change when a moist piece of cobalt chloride paper is put on a hot

plate?

12. Why does road grit contain rock salt?

13. Why does Gordon Ramsay recommend that you put salt in the water when boiling

potatoes?


Solids, Liquids and Gases pg. 31

Particle Theory pg. 32

More Particle Theory pg. 33

Movement of Particles pg. 75

Possible Revision Method—Videos, Animation or Presentation

Make a video or animation to explain a concept.

Create a Presentation and then present to your family or peers to explain the concept.

Create an animation to explain the changes of state using particle theory.

Using tablet apps.

Solution: When a solute combines with a solvent. Transparent in appearance

Mixture: When two substances are put together but do not chemically combine

Dissolving: When a solution is formed. An example of a mixture.

Soluble: Substance can dissolve

Insoluble: Substance cannot dissolve

Saturation: When a solvent has no further space for a solute to dissolve at that

particular temperature

Sedimentation: When an insoluble solid sits at the bottom of a liquid

Suspension: When an insoluble solute sits a top the solvent.

Solute: Solid in a solution.

Solvent: Liquid in a solution.

Because substances in mixtures are not chemically combined they can be separated easily.

Separating Miscible and immiscible liquids

Immiscible liquids are liquids which do not mix together.

e.g. Water and Oil

Immiscible liquids are separated with a separating funnel.

Miscible liquids are liquids which have mixed together

e.g. Alcohol and Water

Miscible liquids are separated using distillation. The liquid with

the lower boiling point evaporates first and is condensed using a

Liebig condenser before collecting.

You need to be able to draw a diagram of simple distillation

Separating Salt from Rock Salt

A three stage process.

1. Rock salt grinded (to increase

surface area making it easier to

dissolve in water) and dissolved

in water to separate soluble salt

from insoluble rock.

2. Solution filtered for further sep-aration of soluble from insoluble.

3. Solution heated to separate

water and salt

Separating Mixtures

Fractional Distillation Simple Distillation

Solubility

The ability of a substance to dissolve and form a solution

Solubility can be affected by the temperature of a solution

Solubility of a substance is usually plotted on a

graph as shown here. As temperature increases

solubility increases.

In some substances solubility increases a lot as

temperature increases, in others the increase is

less

Chromatography Used to separate substances of different solubilities.

Inks contain miscible liquids of different solubilities. The ink is dissolved in the solvent as

it travels up the chromatography paper. The ink that dissolves the best (most soluble)

travels the furthest.

Most Soluble Ink

Least Soluble Ink

Possible Revision Method—Summary Cards

Summary Cards contain the most important details of a topic. You should try to create

a summary of the information, including key words, concepts and diagrams.

Su

mm

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ic: Sep

ara

ting M

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niq

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C

ard

No

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__

____

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Inclu

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on ea

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Questions

If you have revised the previous sheets effectively you should be able to answer the following questions without difficulty.

1. What is a solvent?

2. What is a solute?

3. What is a mixture?

4. What is the appearance of a solution?

5. What is saturation?

6. What are miscible liquids?

7. How are immiscible liquids separated?

8. What property of miscible liquids enable them to be separated by distillation?

9. What is the name given to the apparatus used to condense the gas in distillation?

10. Why is rock salt ground in the first stage of its separation?

11. Why is the ground rock salt placed into water?

12. What happens to the solubility of a solution as it is heated?

13. Using the graph above calculate the solubility of sodium nitrate at 90oC

14. Using the same graph identify which solution has the highest solubility at 20oC

15. Using the same graph identify which solution has the highest solubility at 80oC

16. What is chromatography used to separate?

17. Where would you find the most soluble ink on a chromatogram? Closest to the starting

point or furthest from the starting point?


Mixtures pg. 39

Separating Mixtures pg. 40 and pg. 41

Metals and The Reactivity Series

Metals

Found on the periodic table to the left of ‘the stairs’

Properties of Metals Conducts electricity

Conducts heat

Malleable

Ductile

Shiny (when freshly cut)

Reactivity

Some metals can react with water and most react with acids. How well a metal reacts with another

substance is known as its ‘reactivity’. The Reactivity Series shows the most reactive metals at the

top of the series and least reactive at the bottom.

Some metals react with water to produce Hydrogen gas

e.g. Potassium, Sodium and Calcium

Some metals react with steam and not water e.g.

Magnesium

Some metals do not react with either because they are

too unreactive e.g. Gold and silver. These are used for

building and jewellery e.g. Copper for pipes and Gold

for necklaces.

Metals and Acids

Metals react with acids quite readily. When they react they produce Hydrogen gas.

Metal + Acid Salt + Hydrogen (MASH)

Those in red are non-metals added

for comparison!

Displacement Reactions

A more reactive metal can react with a less reactive metal to displace it.

A more reactive metal can replace a less reactive metal from its oxide

Magnesium + Copper Oxide Magnesium Oxide + Copper

Copper Sulphate + Iron Iron Sulphate + Copper

Displacement reactions can result in large amounts of energy being released Displacement reactions are used to separate pure metals from their ore (natural state) Many metals do not exist in pure form in nature because they are reactive. Displacement

can remove them from their natural state. The Thermit Reaction:

A reaction used many years ago to produce molten iron which was then used to weld

railway line together. Quick and vigorous displacement reaction.

Iron (III) Oxide + Aluminium Aluminium Oxide + Iron

Rusting

Rust forms when Iron reacts with Oxygen and Water to produce Iron (III) Oxide

Look at the experiment to see how we test to see if Water and Oxygen are needed for

rusting to occur.

Rust Prevention:

1. Painting – Waterproofs the iron

2. Oiling – Provides waterproof layer.

3. Galvanising – Coating Iron in Zinc

4. Sacrificial protection – Providing a more reactive metal for Water and Oxygen to react

with instead of iron

Questions



1. Name three properties of metals.

2. Where on the periodic table are metals found

3. Which is more reactive: Magnesium or Iron?

4. Which is less reactive: Sodium or Calcium?

5. Which is more reactive: Carbon or Hydrogen?

6. Which metal reacts with steam but not with cold water?

7. Name two metals that react with cold water?

8. What is produced when a metal reacts with an acid?

9. Complete the following displacement reactions:

a. Iron Oxide + ___________ Magnesium Oxide + __________

b. Copper Sulphate + Iron ________ _______________ + _____________

c. Potassium Oxide + Sodium ___________ ____________ + _____________

d. Iron (III) Oxide + Aluminium ________ _____________ + ____________

e. ________ ________ + ____________ Calcium Oxide + Tin

10. How can you tell that the reaction between copper sulphate and an iron nail results in Iron

Sulphate and Copper? Look at the diagram carefully.

11. What two substances are required for rusting to occur?

12. Name two methods of rust prevention. Explain how they work?


Property of Metals pg. 42 and pg. 43

Property of Non-metals pg. 44 and pg. 45

Reactivity Series and Metal Extraction pg. 40

Displacement Reactions pg. 52

Possible Revision Method—Create a Mnemonic

An mnemonic is a made up rhyme to help you memorise lists of information.

Create an mnemonic to help you memorise the order of metals in the Reactivity Series

Dulwich Prep London

42 Alleyn Park | London SE21 7AA | Telephone 020 8766 5500 | Fax 020 8766 7586 | www.dulwichpreplondon.org

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