UNIT 1

Unit 1aSubstances

Elements (i)

Everything in the world is made from about one hundred ……………………. Each one has a name and a …………………… that consists of one or two letters.

The first letter is always a …………………… letter (upper case) and the second letter is always lower case (a small letter), e.g. the symbol for carbon is ……… but the symbol for …………………… is Ca.

The symbol for some elements is based on the Latin name, e.g. the symbol for potassium (kalium) is ……… and the symbol for …………………… (natrium) is Na.

Chemists have arranged elements in the …………………… …………………… .

Most elements are solid at room temperature, e.g. …………………… and …………………… . The two elements that are liquid at room temperature are …………………… and …………………… .

Some elements are gases at room temperature, e.g. …………………… and …………………… .

Elements can be classified as …………………… and non-metals. There are many more …………………… than …………………… . The metals are found to the …………………… side of the zig-zag line in the Periodic Table.

Some elements, including …………………… , …………………… and …………………… have been known for a long time. The most recently

…………………… elements have been made by scientists. These elements are found after uranium at the …………………… of the Periodic Table.

Elements (ii)

Elements in the same …………………… of the Periodic Table show similar chemical properties, e.g. sodium, …………………… and …………………… are all stored under oil because they are very …………………… .

Elements are used for many things.

Some examples of everyday uses of elements are shown in the table.

Element Use

Aluminium …………………………………………………………

Chlorine …………………………………………………………

Zinc …………………………………………………………

Carbon …………………………………………………………

Iron …………………………………………………………

Argon …………………………………………………………

Compounds and mixtures

A …………………… is a substance that is made up of two or more elements joined together, e.g.

+ iron sulphur iron sulphide

Compounds with a name ending in ‘-ide’ contain the two elements indicated, e.g. the compound that contains calcium and oxygen is called …………………… …………………… .

Similarly, sodium chloride contains …………………… and …………………… .

The name ending ‘-ite’ or ‘-ate’ indicates the additional element …………………… in the compound, e.g. potassium sulphite and potassium sulphate both contain potassium, …………………… and …………………… .

When two or more substances come together without reacting, a …………………… is formed. Air is a mixture of gases, approximately 80% …………………… and 20% …………………… .

The test for …………………… is that it relights a glowing splint. A glowing splint does not …………………… in air because there is not enough oxygen.

Solutions

A solution is formed when a substance …………………… in a liquid.

+ copper sulphate

water coppersulphatesolution

A substance that dissolves in a liquid is …………………… ; a substance which does not dissolve is …………………… .

A solution is …………………… if more liquid is added to it.

A …………………… solution has a lower concentration of dissolved substance than a …………………… solution.

A …………………… solution is one in which no more substance can be dissolved.

The gas which is dissolved in some drinks to make them fizzy is …………………… …………………… . The test for carbon dioxide is that it turns …………………… …………………… milky.

The substance that dissolves in the liquid can be a …………………… , a liquid or a gas, e.g. sugar is a solid that dissolves in water, alcohol is a …………………… that dissolves in water and sulphur dioxide is a …………………… that dissolves in water.

In some places, to kill bacteria, …………………… is added to our drinking water.

To prevent tooth decay, sodium …………………… is added.

Compounds of …………………… , which can get into drinking water from old pipes, can be harmful to health.

Hazards (i)

Regulations on the use of chemicals exist to ensure a …………………… working environment for everyone who comes into contact with chemicals at work.

Simple …………………… warning symbols, which can be easily recognised, are used to identify the potential dangers of all chemicals.

Hazard symbols are on road tankers to indicate dangers in the event of …………………… .

This shows that the chemical is …………………… (a poison). Taking or eating these chemicals would make you feel very …………………… and may even cause death.

This shows that the chemical is …………………… (sometimes called caustic). These chemicals can cause severe …………………… to the skin, as well as holes in some metal objects.

This shows that the chemical is …………………… (sometimes called inflammable, which is the same thing).Flammable chemicals catch fire and …………………… very easily.

Hazards (ii)

This shows that the chemical is an …………………… or harmful chemical. Chemicals with this warning symbol can make you feel very …………………… by affecting your skin or organs. In many cases your …………………… or breathing system can be badly damaged by these chemicals.

This shows that the chemical is …………………… .As you might expect chemicals with this warning symbol can …………………… !

This shows that the chemical is …………………… .Exposure to …………………… can be harmful and may lead to cancer. This is why hospital staff in the …………………… department will wear special (and very heavy) clothes, or they will stand behind a protective screen.

Unit 1b Chemical reactions

Identification (i)

All chemical reactions involve the formation of one or more …………………… substances.

Chemical reactions can be identified by …………………… in the appearance of substances, including changes in colour. Chemical reactions can also be identified by a …………………… being given off or a …………………… (precipitate) forming on mixing two solutions.Some examples of changes that can be observed during chemical …………………… are shown in the table.

Chemical reaction Evidence of a reaction taking place

Making toast …………………………………………

Magnesium with acid …………………………………………

Iron rusting …………………………………………

Chemical reactions can also be identified by …………………… changes that take place, e.g. when an alkali reacts with an acid, nothing is seen but the test-tube becomes …………………… because energy is produced, showing that a chemical reaction is taking place.

Identification (ii)

Some examples of the wide variety of …………………… reactions that occur in the world around us are shown in the table.

Everyday chemical reactions

A nail rusting

Speed of reactions

The speed of a chemical reaction both in the laboratory and in our everyday life can be affected by changes in …………………… size, …………………… of reactants and …………………… of reactants.

Decreasing the particle size …………………… the speed of reaction; decreasing the concentration …………………… the speed of reaction; increasing the temperature …………………… the speed of reaction.

A substance which speeds up a reaction but is not used up by the reaction is called a …………………… . One example of an everyday use of a …………………… is shown in the table.

Catalyst Everyday use

………………… ……………………………………………………

Catalysts which affect reactions in living things are called …………………… .They are used in everyday life.

Some examples of everyday …………………… of enzymes are shown in the table.

Enzyme Everyday use

………………… ……………………………………………………

………………… ……………………………………………………

………………… ……………………………………………………

Word equations

In a chemical reaction, the starting substances are called the …………………… and the new substances that are formed are called the …………………… .A short-hand way of representing a chemical reaction is by a word …………………… .

Consider, for example, the reaction of paraffin with oxygen to form water and carbon dioxide.The reactants are …………………… and …………………… .The products are …………………… and ………………. ………………… .

The word equation for the reaction of sodium with water to form hydrogen and sodium hydroxide is:

…………………… + …………………… …………………… + …………………… ……………………

Another word equation is:ammonia + oxygen nitrogen + water

This word equation describes the reaction between …………………… and …………………… to form …………………… and …………………… .

In a word equation:

• the …………………… sign means and• the …………………… means changes into• the reactants are always written to the …………………… side of the arrow

and the products are always on the …………………… side of the arrow.

Unit 1c Bonding

Molecules and ions (i)

Every element is made up of very small particles called …………………… An …………………… is a substance that is made up of atoms of only one kind.

A silver ring contains millions of …………………… that are all the same.

Every atom in an iron nail is an atom of iron and all atoms of iron are the …………………… .

But an iron atom is …………………… in size and mass from a silver atom.

Each …………………… in the Periodic Table contains a different kind of atom. As well as its own name, each element has its own number, called the …………………… number.

The atomic number for potassium is ……… and the element with the atomic number of 92 is called …………………… .

When scientists make new elements, they make new kinds of atoms, i.e. atoms with a …………………… atomic number from all the rest.

silver ring

ironnail

Molecules and ions (ii)

A …………………… is a group of atoms (two or more) joined together. The joins between the atoms are called …………………… .

Some elements and compounds are made up of …………………… ,

e.g. iodine is an ……………………made up of molecules

and water (hydrogen oxide)is a ……………………made up of molecules.

The bonds inside the molecules are …………………… bonds.

The bonds between the molecules are …………………… bonds.

strong bonds insidethe molecules

strong bonds insidethe molecules

weak bonds betweenthe molecules

weak bonds betweenthe molecules

Molecules and ions (iii)

Ions are atoms that have a …………………… .

There are two types of ion, one with a …………………… charge and the other with a …………………… charge.

The bonds holding the oppositely charged ions together are …………………… .

Some compounds are made up of …………………… , e.g. common salt (sodium chloride).

The sodium ion (symbol Na+) has a …………………… charge. The chloride ion (symbol Cl–) has a …………………… charge.

Substances like sodium chloride that are made up of ions are called …………………… compounds.

Formulae – using models

The chemical …………………… indicates the number of atoms of each element in a molecule of the substance, e.g. the chemical formula O2 shows that there are ……… oxygen atoms in the molecule, the chemical formula CH4 shows that there is …………………… carbon atom and ……… hydrogen atoms in the molecule.

One way of working out the chemical …………………… for a substance is by looking at models or pictures of molecules.

has the chemical formula ………

has the chemical formula ………

This compound has the chemical formula ………

while has the chemical formula ………

Formulae – using prefixes

Some compounds have a …………………… at the start of the name that enables us to write the chemical formula directly from the name.

Prefix Meaning

Name Formula

……… 1 Carbon monoxide ………

……… 2 …………………… ……………………

CO2

Tri ……… …………………… ……………………

SO3

Tetra ……… Silicon tetrachloride ………

So will have the chemical formula ………

phosphorus trihydride

Unit 1d Acids and alkalis

The pH scale

The ……… scale is used to measure the acidity (or alkalinity) of a chemical.

The chemical must be dissolved in water, i.e. it must be a…………………… for the pH to be measured.

The pH of a solution is usually measured using pH …………………… or …………………… indicator. The pH is found by …………………… the colour of the paper or indicator with a colour chart.A pH …………………… can be used to find the pH of a solution without the need to match with a colour chart.

The pH scale ranges from pH number ……… up to pH number ……… . Solutions that have a pH of below 7 are …………………… ; solutions that have a pH above 7 are …………………… . The pH of water and …………………… solutions is 7.

The lower the pH of an acid, the …………………… the acidity; a solution with a pH of 2 is …………………… acid than a solution with a pH of 6.

The …………………… the pH of an alkali, the greater the alkalinity; a solution with a pH of 14 is …………………… alkaline than a solution with a pH of 10. Solutions are …………………… by the addition of water.

As an acid solution is diluted, the acidity of the solution …………………… and the pH …………………… . As an alkaline solution is diluted, the alkalinity of the solution …………………… and the pH …………………… .

Common acids and alkalis

hydrochloric sodium hydroxide lemonade oven cleaneracid solution

Acids and alkalis are used in the …………………… , in industry and in school.

Common laboratory acids include …………………… acid, …………………… acid and …………………… acid.

Common laboratory alkalis include sodium …………………… solution, …………………… water and …………………… solution.

Common household acids include …………………… , …………………… and …………………… water.

Common household alkalis include …………………… soda, …………………… cleaner, …………………… powder, bleach and soaps.

Neutralisation (i)

Acids have a pH of …………………… than 7; alkalis have a pH of …………………… than 7. When an alkali is added to an acid, the reaction that takes place …………………… the pH of the acid.

When an acid is added to an alkali, the reaction that takes place …………………… the pH of the alkali.

When an acid reacts with an alkali the pH of both solutions moves towards ……… .

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

Since a solution with a pH of 7 is neutral, the type of reaction which takes place is called …………………… . A neutral solution is produced because the acid and the alkali react to form …………………… . The other product of the reaction is called a …………………… .

The general word equation for an acid/alkali reaction is:

…………………… + …………………… …………………… + ……………………

The name of the salt comes from the acid and the …………………… .

The first part of the name comes from the …………………… of the alkali, e.g. sodium hydroxide forms …………………… salts and…………………… hydroxide forms potassium salts.The second part of the name comes from the …………………… , as shown in the table below.

Name of acid Name of salt formed

Hydrochloric A type of …………………………………………

Sulphuric A type of …………………………………………

Nitric A type of …………………………………………

Neutralisation (ii)

The names of some …………………… formed in acid/alkali reactions are shown in the table below.

Name of alkali Name of acid Name of salt formed

Sodium hydroxide Hydrochloric ……………… ……………….

…………… hydroxide

Nitric Lithium nitrate

Potassium hydroxide

…………………… Potassium sulphate

So the word equation for the reaction of sodium hydroxide with sulphuric acid is:

…………………… …………………… + ……………… acid …………………… …………………… + ……………………

Carbon dioxide gas is produced in the reaction of an acid with a metal …………………… .

The gas can be identified because it turns …………………… …………………… milky. The other two products of this type of reaction are a …………………… and …………………… .

Since water is formed in the reaction of an acid with a metal carbonate, the type of reaction is again called …………………… .

The general word equation for an acid/metal carbonate reaction is:

…………………… + …………………… …………………… …………………… + …………………… + …………………… ……………………

acid metal carbonate

So the word equation for the reaction of iron carbonate with hydrochloric acid is:

…………………… …………………… + …………………… ……………………

……………… ……………… + ……………… + ……………… ………………

Copper sulphate can be made by the reaction of …………………… carbonate with …………………… acid. The unreacted solid copper carbonate can be removed from the solution by …………………… .

A solid sample of the salt can be obtained by heating the solution with a bunsen burner to …………………… the water.

Treatment of …………………… indigestion is an everyday example of neutralisation. The indigestion tablet contains a chemical that …………………… the pH of the acid in the stomach. Other everyday examples of neutralisation involve the use of chemicals to reduce the …………………… of the soil and lakes.

excesscoppercarbonate

coppersulphatesolution

evaporatingbasin

tripod

gentle heat

Acid rain

When carbon and sulphur burn, they react with …………………… to form gases. Carbon reacts to form …………………… dioxide; sulphur reacts to form sulphur …………………… , a gas with a very unpleasant …………………… .

Although nitrogen does not burn in the same way as carbon and sulphur, the gas does react with oxygen to form the brown gas called …………………… …………………… . Carbon, sulphur and nitrogen are all …………………… elements.

The gases produced all dissolve in water to form …………………… solutions.

Sulphur dioxide is produced in the air when the …………………… that is found in some fossil fuels also burns.

The sparking of air in car engines forms …………………… dioxide. Sulphur dioxide and nitrogen dioxide dissolve in water in the atmosphere to produce …………………… rain.

Acid rain is destroying ……………………

Acid rain has increased the …………………… of water in rivers and lochs.

Some examples of the …………………… effect of acid rain on structures made of carbonate rock and iron or steel, soils, and plant and animal life are shown in the table below.

Effect on: Damaging effect

Carbonate rock …………………………………………………………

Iron and steel …………………………………………………………

Soil …………………………………………………………

Plant life …………………………………………………………

Animal life …………………………………………………………

UNIT 2

Unit 2a Metals

Uses (i)

Metallic elements are to the …………………… side of the zig-zag line in the Periodic Table. A few metals, including …………………… , …………………… and …………………… , are found in the Earth’s crust as the free element. Most metals are found …………………… with other elements.Most metals have to be …………………… from their ores before they can be used.

Some metals, including iron, are extracted from their ores by heating with …………………… . Iron is extracted from its ore in a …………………… furnace. Some metals, including aluminium, are extracted from their ores using …………………… .

All metal elements are …………………… of electricity. Elements that are …………………… do not conduct electricity; carbon in the form of …………………… is an exception.

The use that we make of a metal depends on its specific …………………… .

Property What it means

Thermal conductivity How well a metal conducts ……………………

Electrical conductivity

How well a metal conducts ……………………

…………………… How strong a metal is

…………………… How heavy a certain volume of metal is

…………………… How easily a metal can be shaped

Uses (ii)

Some examples of how the …………………… of metals are related to their properties are shown in the table below.

Metal Use Property

…………………… …………………… ……………………

…………………… …………………… ……………………

…………………… …………………… ……………………

An …………………… is a mixture of metals. Brass, solder and stainless steel are examples of …………………… .

Some examples of the …………………… of alloys are shown in the table below.

Alloy Use

Cupro-nickel …………………………………………...………

Solder …………………………………………...………

‘Stainless’ steel …………………………………………...………

Reactions (i)

Metals take part in some important chemical …………………… .

Metal oxides are produced in the reactions of metals with …………………… , e.g. magnesium reacts with oxygen to form …………………… …………………… .

Lithium, …………………… and …………………… are all kept under …………………… to protect them from the atmosphere. These metals react slowly with the …………………… of the air.

However, these metals react…………………… with water.

The speed of the reaction of …………………… metal with water is suitable for the collection of the gas produced. The gas produced when a metal reacts with water is called …………………… gas. The test for hydrogen is that it burns with a …………………… .

Metals that react with …………………… also produce hydrogen gas. A …………………… that takes its name from the metal and the acid is also formed, e.g. zinc reacts with hydrochloric acid to produce zinc …………………… and …………………… , magnesium reacts with …………………… acid to produce magnesium sulphate and hydrogen.

Some metals, including …………………… , …………………… and …………………… , do not react with dilute acid.

Differences in the reactions of metals with …………………… , …………………… and …………………… give an indication of the …………………… of the metals. This is shown on page ……… of the data booklet.

safety screen

water

metal

Reactions (ii)

Iron is …………………… reactive than aluminium; zinc is …………………… reactive than copper. An example of a metal that reacts with oxygen is …………………… ;an example of a metal that does not react with oxygen is …………………… . An example of a metal that reacts with water is …………………… ; an example of a metal that does not react with water is …………………… . An example of a metal that reacts with acid is …………………… ; an example of a metal that does not react with acid is …………………… .

Corrosion (i)

When some …………………… are left in the open air, they tend to break up at the surface. The metal object gradually disappears as the …………………… flakes off. This process is called …………………… and in the special case of iron it is called …………………… . Rusting results in the iron losing its …………………… .

Iron does not rust in a test tube of dry air showing that …………………… is required for rusting to take place.

Iron does not rust in water that has been boiled showing that …………………… (from the air) is required for rusting. Iron rusts in moist air because both …………………… and …………………… are present.

When iron rusts, the surface of the metal changes from an element to a …………………… . The iron …………………… in the element react to form iron ions in the compound.

A rust …………………… can be used to detect iron ions and hence measure the amount of rusting that takes place. The more …………………… colour, the more rusting there is.

cotton wool

drying agent

stopper

moist air

oil film

boiled water

Corrosion (ii)

tap water acid rain salt water+ + +

rust indicator rust indicator rust indicator

In the above experiment, there is more blue colour around the nail in the …………………… rain than the nail in the tap water. This shows that iron rusts …………………… in acid rain. Because of the higher levels of acid rain, cars in city areas usually rust …………………… than cars in country areas.

There is more blue colour around the nail in the ……………………water than around the nail in the tap water. This shows that iron rusts …………………… in salt water. Putting winter salt on the roads …………………… the speed of rusting of a car. Also, car owners who live near the sea should wash their cars more than owners who live inland to remove the …………………… .

Iron can be …………………… from rusting by making a surface barrier that prevents …………………… and …………………… from coming into contact with the iron. There are several relatively inexpensive ways of doing this, e.g. …………………… , …………………… and coating with plastic. When iron is galvanised, it is dipped into molten …………………… to coat the iron with that metal, e.g. for …………………… .

In …………………… , electricity is used to cover iron with a thin layer of a new metal, e.g. chrome on bicycles.

Cans containing food are …………………… to prevent corrosion.

Iron can also be protected by attaching the iron to certain other …………………… . This method of protection is very different from providing a …………………… barrier.

Corrosion (iii)

iron nail in magnesium zinc attached tin attachedrust indicator attached to to iron nail to iron nail

iron nail

There is no blue colour around the nails attached to …………………… and …………………… showing that the nails are not rusting. The metals that protect iron in this way are all …………………… reactive than the iron itself. Since zinc is more reactive than iron, …………………… (coating iron with zinc) provides this kind of protection as well as providing a surface barrier.

Bags of scrap …………………… (a …………………… reactive metal than iron) are attached to underground iron and steel pipes to protect the iron in this way.

Aluminium is a …………………… reactive metal than iron and yet it does not appear to corrode. Aluminium tends to be slow to react because it is usually covered by a thin layer of aluminium …………………… . The process of using electricity to increase the thickness of the oxide layer, providing increased protection against corrosion, is called …………………… .

Batteries

When a battery is in use the …………………… in the battery react to make electricity. Chemical energy is changed to …………………… energy.

When all the chemicals are used up by the chemical …………………… , the battery can no longer make electricity, i.e. the battery is ‘dead’ and it has to be …………………… .

Batteries that can be …………………… are able to be used over and over again, e.g. the …………………… battery that is used in cars and the …………………… battery.

Electricity can be produced by connecting two different …………………… together to make a cell.

A solution containing ions is needed to …………………… the circuit between the metals. The voltage is related to the difference in the …………………… of the metals. Magnesium joined to silver will produce a …………………… voltage than magnesium joined to copper.

Zinc joined to iron will produce a …………………… voltage than zinc joined to tin.

voltmeter

metal 2

magnesium

filter paper soaked in ion solution

Unit 2b Personal needs

Keeping clean

When cleaning hair, skin and clothes, it is difficult to remove …………………… and …………………… by washing with water.

They are difficult to remove because they are …………………… in water. Cleaning chemicals enable oil and grease to …………………… with the water. These chemicals break up the oil and grease into tiny …………………… .

This happens because the cleaning chemicals are …………………… in both oil and grease and water.

Examples of manufactured products that contain cleaning chemicals include …………………… , …………………… , …………………… and …………………… liquids and powders.

…………………… water contains certain dissolved compounds that are not found in soft water. Soaps that form a …………………… in soft water can form a …………………… with hard water. As a result, …………………… detergents are used to produce a lather with hard water.

Dry cleaning uses special solvents that are particularly good at …………………… oil and grease stains.

oil

water oil droplets in water

Clothing

Clothing fabrics are made from thin strands called …………………… .

Fibres are made up of long-chain molecules called …………………… . Fibres can be classified as …………………… (made from plants or animals) or …………………… (made by the chemical industry).

Examples of natural fibres include …………………… , …………………… and …………………… .

Examples of synthetic fibres include …………………… and …………………… , e.g. Terylene.

Fibres that are …………………… can be designed to have the specific properties needed for a particular use.

…………………… are coloured compounds that are used to produce brightly coloured fabrics. Most dyes require the use of a compound to ‘fix’ the dye to the fabric and make the colour …………………… .

Sometimes fabrics can be treated with chemicals to improve their properties, e.g. …………………… …………………… a fabric for children’s clothes.

Fibres that form …………………… bonds with water molecules are hard to drip-dry but they do not feel ‘sweaty’ to wear because they soak-up perspiration.

woollen jumper

Terylene trousers

Unit 2c Fuels

Fire (i)

A fuel is a chemical that is burned to produce …………………… . When a substance burns it …………………… with oxygen.

…………………………. is another word for burning. As well as a …………………… , a fire needs …………………… (usually from the air) and a …………………… high enough to start the fire and keep it going. This is shown in the …………………… triangle.

Perhaps the most frequent way to fight a fire is to pour …………………… on to the flames of the fire, e.g. a bonfire. However, …………………… must not be used with oil, petrol and electrical fires.

A fire …………………… can be put over the flames or …………………… …………………… gas or foam from a cylinder can be used both in the lab and at home, e.g. for a chip-pan fire.

In the lab there will also be a bucket of …………………… for fighting fires.

Fire (ii)

Fire-fighting methods try to remove any one of what is at the three sides of the fire …………………… . When this happens the …………………… goes out.

Fire-fighting method What is removed

Covering burning oil with a towel ……………………

Spraying water on a bonfire ……………………

Controlled burning of trees in the path of a forest fire

……………………

Spraying carbon dioxide on a burning car

……………………

Pouring sand on burning magnesium

……………………

Finite resources (i)

Most of the fuels that we use today are made from the remains of …………………… and animals. Over many …………………… of years, the pressures and temperatures under the ground change the remains to produce the fuels. The fuels formed in this way are known as …………………… fuels.

Examples of fossil fuels include …………………… , …………………… , …………………… gas and peat.

Fossil fuels are a …………………… resource, i.e. they cannot be replaced when they have been used.

Over-use of fossil fuels could lead to a fuel …………………… , i.e. there could be a shortage of fuels or the supply could even run out. To …………………… our supplies of fossil fuels, …………………… should be saved whenever possible, e.g. by turning out lights and not overheating rooms.

Finite resources (ii)

Fossil fuels have to be transported by oil …………………… around the world to where they are most needed. This can lead to oil …………………… at sea. When this happens serious damage can be caused to marine life, e.g. oil on the feathers of …………………… , and to the sea-side …………………… in general, e.g. oil on sandy beaches.

The chemical compounds found in fossil fuels are mainly …………………… . A hydrocarbon is a compound that contains …………………… and …………………… only, e.g. butane, C4H10, is a …………………… but acetone, C2H6O, is not.

When a hydrocarbon burns in a plentiful supply of air, the hydrogen and carbon atoms in the compound both react with …………………… . The two products of the reaction are …………………… …………………… and …………………… .

Carbon dioxide can be identified because it turns lime water …………………… while water can be identified by its …………………… point of 100°C.

Renewable resources

New fuels that are …………………… sources of energy, i.e. able to be replaced, can be used instead of fossil fuels.

Biogas can be generated by the …………………… of waste plant material. The main renewable source of energy in biogas is …………………… . The renewable source of energy that can be obtained from sugar cane is …………………… . This can be mixed with petrol to make a fuel for …………………… .

Hydrogen, a renewable source of energy obtained from …………………… , is a likely fuel for the future.

Important processes (i)

A mixture of liquids can be separated by using the difference in …………………… points, e.g. …………………… and water are separated in the manufacture of whisky in a distillery. This type of separation process is called …………………… .

Distillation of liquid air is used in industry to separate oxygen and …………………… .

The process of distillation involves heating a liquid until it boils to form a …………………… and then cooling the gas somewhere else to make it …………………… into a liquid.

The boiling point is related to the …………………… of the molecules in the liquid.

Crude oil is a …………………… of chemical compounds, mainly hydrocarbons. Before it can be used, the many different liquids and dissolved solids and gases in it have to be separated into …………………… that contain compounds of roughly the same …………………… point. This process is called …………………… …………………… .

The largest molecules are found in the fraction with the …………………… boiling point; the smallest molecules found in the fraction with the …………………… boiling point.

The fractional distillation of crude oil produces many useful …………………… .

crude oil in heater

bitumen residue

bottled gas & chemicals4 carbon atoms

petrol, chemicals & solvents5 to 10 carbon atoms

diesel and heating oil14 to 20 carbon atomslubricating oil & greases20+ carbon atoms

kerosene & paraffin10 to 16 carbon atoms

Important processes (ii)

A use for each of the …………………… is shown in the table below.

Name of fraction Use

Gas ……………………………………………………

Petrol ……………………………………………………

Diesel ……………………………………………………

Kerosene ……………………………………………………

Lubricating oil ……………………………………………………

Bitumen ……………………………………………………

The process of …………………… distillation can be simulated in the laboratory.

The uses of the fractions are related to the boiling point ranges, ease of evaporation, flammability and …………………… (thickness) of the fractions.

Gas Petrol Diesel Kerosene (Paraffin)

Lubricating oil

Bitumen

-------- Lighter / darker in colour -------------------------------->

--------- Increase / decrease in boiling point --------------------->

--------- Increase / decrease in ease of evaporation ------------->

---------- Increase / decrease in viscosity ------------------------>

---------- Increase / decrease in molecular size ------------------>

Important processes (iii)

Fractional distillation produces more molecules that are …………………… in size than are needed that for present-day industrial purposes.

Fuel gas Petrol NaphthaKerosene Diesel Fuel oiloil and bitumen

These less popular molecules can be broken up to produce more of the smaller molecules that are more …………………… . This process is called …………………… .

The cracking of the hydrocarbon with the chemical formula …………………… can produce the hydrocarbon products shown in the table below.

Reaction Reactant Formulae of molecules produced

1 C12H26 C10H22 + ………

2 C12H26 C8H16 + ………

3 C12H26 C5H12 + C2H4 + ………

Name of fractions

Pollution problems (i)

Air …………………… is a result of impurities in the air. Most of these pollutants come from the burning of …………………… fuels such as oil and petrol. Air pollution is therefore more of a problem in …………………… areas.

When a hydrocarbon fuel burns in a good supply of oxygen, the carbon reacts with oxygen in the air to form carbon …………………… .

When there is a poor oxygen supply, e.g. in a car engine, carbon …………………… is also produced. Carbon monoxide is dangerous because it is a …………………… gas. This gas reacts with haemoglobin in the blood, stopping it carrying …………………… to the brain and other parts of the body. In Tokyo, traffic police wear …………………… masks at the rush-hours to protect them from carbon monoxide pollution.

Carbon is also a product of burning hydrocarbons in a poor supply of oxygen and …………………… particles produced by the burning of diesel are also potentially harmful.

Compounds of …………………… that are added to petrol cause pollution. In this country nearly all cars run on unleaded …………………… . However, different hydrocarbons are used to make unleaded petrol and the …………………… fumes in unleaded petrol are toxic.

Since crude oil contains small amounts of sulphur, the burning of fuels obtained from crude oil produces …………………… …………………… . This gas dissolves in rain water to form …………………… rain, which attacks iron and the stonework of buildings as well as plants and trees. To reduce air pollution sulphur compounds can be removed from petrol and used to manufacture …………………… acid.

Pollution problems (ii)

Nitrogen and …………………… in the air do not normally react but the spark that ignites the petrol can provide the …………………… to produce a reaction. As a result, oxides of …………………… , which are also poisonous gases, are found in car exhaust fumes as well.

Special exhaust systems with …………………… converters speed up the conversion of pollutant gases to harmless gases. These systems contain …………………… metals (metals in the rows in the middle of the Periodic Table), which act as …………………… for these reactions.

Unit 2d Plastics

Uses

Plastics are not …………………… materials like wood and stone. They are …………………… materials, i.e. made by the chemical industry.

Most plastics are made from …………………… …………………… .

Examples of plastics include …………………… , …………………… , …………………… , …………………… , …………………… , …………………… , …………………… and …………………… .

The everyday …………………… of plastics are related to their properties.

Plastic Property Use

…………………… …………………… ……………………

…………………… …………………… ……………………

…………………… …………………… ……………………

Advantages and disadvantages (i)

Many natural and …………………… materials are used for the same purpose. Materials like wood, glass, metals and paper can now be replaced by …………………… .

Some advantages of …………………… materials and plastics are shown in the tables.

Natural material Use Advantage

…………………… …………………… ……………………

…………………… …………………… ……………………

…………………… …………………… ……………………

Plastics Uses Advantage

…………………… …………………… ……………………

…………………… …………………… ……………………

…………………… …………………… ……………………

Plastics are quite cheap, light and can be easily …………………… into different shapes.

However, the …………………… and …………………… of plastics can cause problems.

Advantages and disadvantages (ii)

The leaves from the trees are …………………… , i.e. able to be broken down by bacteria and weather. ‘Bio’ refers to …………………… things and …………………… means ‘able to rot away’.

Since …………………… are not biodegradable this leads to an unsightly environment that can be dangerous to animals.

To help with the disposal of plastic waste, chemists are investigating the development of …………………… plastics.

Further problems can arise with the …………………… of plastics, e.g. fires involving plastics are extremely dangerous.

Carbon monoxide, a …………………… gas can be given off from just about any burning plastic.

Other gases produced depend on the elements in the plastic, e.g. PVC contains chlorine and so burning PVC can produce hydrogen …………………… .

Options for the …………………… of plastics include incineration, recycling and burying. With …………………… , the heat generated can be used as a source of energy but there are problems with emissions.

plastic litter is unsightly

Since plastics are made from …………………… …………………… , which is a finite resource, …………………… is to be encouraged and special containers are available in many places for this purpose.

However, recycling can be …………………… because of the many different kinds of plastics in common use.

To conserve oil supplies, chemists are looking for ways of making plastics from …………………… sources.

plastic waste

Thermoplastics/thermosetting plastics (i)

Plastics can be classified according to what happens to them when they are …………………… . Plastics that soften on heating are known as …………………… (thermosoftening plastics). This enables them to be …………………… over and over again. Examples of thermoplastics include …………………… and …………………… .

Plastics that harden on heating are known as …………………… plastics.They cannot be reshaped because they do not …………………… on reheating. Examples of thermosetting plastics include……………………………… and ……………………………… .

The uses of thermosetting plastics depend on their two main properties, i.e. they do not soften on …………………… and they do not conduct …………………… . Electrical plugs and sockets and kitchen worktops are made from …………………… plastics.

Thermoplastic/thermosetting plastics (ii)

Plastics are made of very …………………… molecules containing hundreds of carbon atoms linked together to make a chain.

The large molecule is called a …………………… .

Polymers are made by the joining together of …………………… molecules. The small molecule is called a …………………… .

The process of making a polymer from monomer units is called …………………… .

The names of polymers are related to the names of the …………………… from which they are made, as shown in the table below.

Name of monomer Name of polymer

Ethene Poly(ethene)

Styrene ……………………

…………………… Poly(propene)

…………………… Poly(chloroethene)

UNIT 3

Unit 3a Photosynthesis and respiration

Photosynthesis

Plants make their own …………………… by taking in substances from the environment. This process is called …………………… .

Plants use …………………… from the air to make glucose. This gas is absorbed through the …………………… of plants. The other reactant is …………………… , which is taken in from the soil through the …………………… of plants.

As well as glucose, a gas which …………………… a glowing splint is also formed. This is …………………… and it is released into the air through the …………………… of the plants.

The ‘photo’ part of photosynthesis indicates that …………………… energy is required for the process to take place. The …………………… in the leaves absorbs the light energy required for photosynthesis. Chlorophyll is the chemical that gives plants their …………………… colour.

The word equation for the photosynthesis reaction is:carbon dioxide + …………………… …………………… + oxygen

Respiration

Animals can obtain energy by a process called …………………… .The reactants are …………………… and …………………… . Animals obtain glucose by eating food that has come from …………………… .When exhaled air is blown into lime water, the lime water turns …………………… . This shows that …………………… …………………… is one of the products of respiration. Also produced in respiration is …………………… .

The energy produced in the process is used in a wide variety of ways, e.g. for …………………… and …………………… .

The word equation for the respiration reaction is:glucose + …………………… carbon dioxide + ……………………

Respiration is the …………………… of photosynthesis. The processes of photosynthesis and respiration maintain …………………… amounts of oxygen and carbon dioxide in the air. The …………………… used up in respiration is produced by photosynthesis; the carbon dioxide produced by …………………… is used up by photosynthesis.

……………………

……………………

glucose oxygen carbon dioxide water

energy

………

energy

………

The greenhouse effect (i)

Carbon …………………… in the atmosphere is one of the main causes of the greenhouse effect. The greenhouse effect is important because it prevents temperatures on the Earth becoming too …………………… for normal life to exist.

Carbon dioxide is removed from the atmosphere by the process known as …………………… . Extensive clearing of …………………… reduces the amount of carbon dioxide removed in this way.The …………………… of fossil fuels produces carbon dioxide. Increased levels of carbon dioxide in the atmosphere may also be due to an …………………… in the combustion of such fuels.

Sun

Earth

carbon dioxide layer

The greenhouse effect (ii)

An …………………… in the level of carbon dioxide in the atmosphere could cause the atmosphere to retain more of the Sun’s …………………… as heat. This process is known as …………………… warming.

Sun

Earth

carbon dioxide layer

Unit 3b The effect of chemicals on the growth of plants

Using chemicals to save plants

Farmers and gardeners use …………………… to try to ensure a good crop yield.

…………………… are used to control pests; pests …………………… the crops.Fungicides are used to prevent …………………… that are caused by bacteria and fungi; diseases lead to poor …………………… of plants.…………………… are used to kill weeds; weeds can inhibit the …………………… of plants by using up essential chemicals in the soil. Pesticides, fungicides and herbicides are …………………… and so must be used with great care. Natural …………………… (animals that eat other animals) can also be used to safely control pests, e.g. …………………… in the garden eat a wide variety of insects.

herbicide

fungicide

pesticide

Fertilisers (i)

Nitrogen (symbol ………), …………………… (P) and …………………… (K) are essential elements for healthy plant growth. These elements are taken in from the soil through the …………………… of plants. The elements are taken in as …………………… and not as the free elements. To be taken in by plants, the compounds are dissolved in water, i.e. in …………………… .

In areas of natural vegetation, e.g. woodland, the …………………… of plant and animal remains returns all essential elements to the soil. However, where crops are harvested and the essential elements removed, …………………… must be added to the soil to restore the elements required for healthy growth of plants. Fertilisers are known as NPK compounds as they contain …………………… , …………………… , and …………………… .

…………………… fertilisers are produced by the natural breakdown of plant and animal remains. Examples of natural fertilisers are …………………… and …………………… . Fertilisers that are made by the chemical industry are said to be …………………… .

The …………………… in the demand for food production has resulted in greater use of artificial fertilisers. The major artificial fertilisers are potassium, nitrate, …………………… and …………………… compounds.

Type of compound Essential element in it

Ammonium …………………………………………………

Nitrate …………………………………………………

Potassium …………………………………………………

Phosphate …………………………………………………

soil

nitrogencompounds

phosphoruscompounds

potassiumcompounds

Fertilisers (ii)

Potassium nitrate can be made by the reaction of an …………………… with an alkali.

The word equation for the reaction is:

…………………… acid + potassium ……………………

potassium nitrate + ……………………

To be effective, the compounds in fertilisers must be …………………… in water.However, the extensive use of artificial fertilisers has …………………… the levels of nitrate compounds in some rivers and lochs. The presence of large quantities of nitrate compounds can leave the water …………………… .

Some plants have root nodules in which …………………… from the air is converted into nitrates. These compounds include …………………… , …………………… and …………………… .

Unit 3c Food and diet

Elements in the body

A variety of …………………… are needed to supply the different chemical elements and compounds required by the body.

A …………………… diet has a good mix of the different types of food and is therefore a ……………………diet.Essential compounds include …………………… , …………………… and …………………… .

More than 60% of body weight is made up of …………………… .The main elements in the compounds in the body are …………………… , …………………… , …………………… and …………………… . These elements are present in the body as …………………… and not as free elements.

Minerals supply the body with …………………… , which is required for strong bones and teeth, and …………………… , which is important for healthy blood.

Elements that are only needed in very minute quantities are called …………………… elements. These elements are also supplied by …………………… . Some trace elements if taken in too large quantities are …………………… , i.e. they act as a poison.

Different carbohydrates

Carbohydrates form an important class of food made by …………………… . Carbohydrates are needed by the body to provide …………………… . Foods rich in carbohydrates include …………………… , …………………… and …………………… .Carbohydrates are compounds that contain the elements …………………… , …………………… and …………………… .

Carbohydrates can be divided into …………………… and starches. Examples of sugars include …………………… (table sugar), …………………… , …………………… and …………………… .Most sugars can be detected by …………………… solution. The sugar that is an exception is …………………… . When the result of a test for a sugar is positive, the solution, on heating, turns from a …………………… colour to an orange-red colour.

…………………… solution is used to test for starch. When the result of a test for starch is positive the solution turns from a wine-red colour to a …………………… colour.

Sugars have a …………………… taste and are very …………………… in water. Starch does not have a …………………… taste and does not …………………… in water.

Reactions of carbohydrates

Sugars dissolve in water; they are made up of molecules that are …………………… in size. Starch does not dissolve in water; starch is made up of very …………………… chain molecules.Very long-chain molecules, like starch, are examples of …………………… . The small molecules that join together to make starch are examples of …………………… .Starch is made by the joining together of molecules of …………………… .

Plants convert the glucose into starch for storing …………………… .During the …………………… of starchy foods, the starch is broken down into …………………… . Glucose is transported round the body in the …………………… . Body cells pick up the glucose and use it for the process called …………………… .

Starch is broken down in the body by …………………… (biological catalysts).Body enzymes work best at body temperature (……… °C). At higher temperatures, body enzymes are …………………… . In the lab, starch can be broken down by …………………… as well as by enzymes.

Fats and oils

Fats and oils form an important class of food obtained from both plants and …………………… . Fats and oils are much more concentrated sources of …………………… than carbohydrates.

Fats and oils can be detected by a special test using …………………… paper. The fat or oil leaves a …………………… stain on the paper.

Saturates are compounds that are made up of molecules that are said to be …………………… ; unsaturates are compounds that are made up of molecules that are said to be …………………… . Compounds that are made up of long chain molecules (……………………) that are said to be unsaturated are known as …………………… .

Saturates are believed to increase the …………………… level in the bloodstream. Medical opinion suggests that total …………………… consumption should be reduced and, where possible, foods with polyunsaturates should be eaten. Foods containing polyunsaturates are considered less likely to cause …………………… disease.

Proteins

Proteins form an important class of food obtained from both plants and …………………… . Foods rich in proteins include …………………… and …………………… . Proteins provide material for body …………………… and repair, e.g. growth of hair and …………………… . Proteins can be detected by heating with …………………… lime and testing for an alkaline gas, i.e. a gas that turns pH paper a …………………… colour.Proteins are chemical compounds made up of the elements …………………… , …………………… , …………………… and …………………… .

Very large long-chain molecules, like proteins, are examples of …………………… . The small molecules that join together to make proteins are examples of …………………… .The monomer molecules that join together to make proteins are …………………… acid molecules. The process of making proteins from amino acids is called …………………… .During …………………… , proteins in foods are broken down to amino acids.

The amino acids required to make animal proteins can be obtained from foods that come from both …………………… and vegetables. A …………………… diet must include a wide variety of foods to supply all the necessary amino acids. The amino acids are then used by animals to make …………………… for specific purposes, e.g. human hair, wool on sheep.

Fibres, vitamins and food additives

Fibre is an essential part of a …………………… diet. Foods rich in fibre include…………………… and …………………… .Fibre absorbs …………………… and swells up. The swollen fibre provides bulk for the …………………… to work on as food is squeezed along the gut. This keeps the gut working well and helps to prevent …………………… . Vitamins are a collection of complex compounds all containing the element …………………… . They are needed to keep the body …………………… .

Food …………………… are added to foods for a variety of reasons. Vitamins and minerals are added to enhance the …………………… value of food. Food preservatives enable food to be kept for …………………… . Food colourings are used to improve the ……………………of food.

Food flavourings add to the …………………… of food. Food additives can be used only if they have been …………………… and approved.

Unit 3d Drugs

Alcohol (i)

A drug is a substance that …………………… the way the body works. Alcohol is a drug; if taken in excess, alcohol can have …………………… effects on health and affect lifestyle.

In the body, alcohol can cause particular damage to the …………………… and a transplant may be needed in extreme cases. Alcohol can also affect the …………………… , e.g. the time for a driver of a car to react is …………………… after drinking alcohol.

The level of alcohol in …………………… drinks can be stated in units. A bottle of alcopop or a pint of beer contains approximately ……… units of alcohol. A pub measure of spirit or a glass of wine contain approximately ……… unit of alcohol. Alcohol is broken down by the body at about 1 unit per …………………… .

Alcohol for alcoholic drinks can be made from …………………… and sugars present in fruit and vegetables. The type of alcoholic drink varies with the …………………… source of the carbohydrate.

Alcohol (ii)

The production of alcoholic drinks from carbohydrates occurs by a process called …………………… . The carbohydrate that reacts is …………………… . Yeast provides the enzymes that act as a …………………… for the reaction. The alcohol produced by fermentation is called …………………… . During fermentation, …………………… …………………… gas is also produced.

The word equation for the reaction is:…………………… …………………… + carbon dioxide

Water and alcohol can be partially separated because they have different …………………… points. This process is called …………………… .

It is a method of …………………… the alcohol concentration of alcoholic drinks.

Other drugs

Some drugs are legal, other drugs are …………………… .

Drug Legal or illegal

Alcohol ……………………Caffeine ……………………Cannabis ……………………Ecstasy ……………………Nicotine ……………………LSD ……………………

Being unable to manage without a drug is known as …………………… .Methanol, another alcohol, is very …………………… . Drinking methanol can cause …………………… and evendeath. Methylated spirits (meths) contains …………………… . It has both a …………………… and a bad tasting substanceadded to it to deter people from …………………… it.

The drugs that doctors use to try to cure illnesses are found in …………………… . These drugs help to maintain the important chemical …………………… that are going on all the time in our bodies. Diseases and infections can be caused by …………………… interfering with these chemical reactions. Some drugs, including …………………… , can fight the micro-organisms. Medicines may be made of several chemicals but only the …………………… ingredients work on the body.