C1 Revision Material

Transcription

1 C1 Revision Material

2 Why do we cook food? Kill microbes Improve texture Improve taste Improve flavour Makes food easier to digest

3 What happens to protien during cooking? For example: egg change from colourless to white during cooking. This is because the protein in the egg permanently changed shape ( ), denatured an irreversible chemical change.

4 Cooking Potatoes List the differences between raw and cooked potatoes. Colour Texture cooked are softer Taste cooked are sweeter HEAT What has cooking done to the chemicals that potatoes are made of?

5 Cooking Potatoes Being plants are made of typical plant cells Which have cell walls made of a CELLULOSE.

6 Close up of cell walls Cooking Potatoes We cannot digest cellulose (also called fibre) What is it made from? Glucose

7 Cooking Potatoes What does cooking do to CELLULOSE? Cellulose is broken down into smaller molecules Which are easier to digest and make the potato taste sweeter

8 Why do we cook potatoes? Explain why potato is easier to digest if it is cooked: o cell walls rupture resulting in loss of rigid structure and a softer texture o starch grains swell up and spread out.

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11 C1f Cooking Additives Baking Powder Objectives 1. Explain the use of baking powder in cooking.

12 Equations- These will be tested Word equation sodium hydrogencarbonate sodium carbonate carbon + + dioxide water Formula equation 2NaHCO 3 Na 2 CO 3 + CO 2 + H 2 O

13 How do we test for carbon dioxide? To test for carbon dioxide we pass it through limewater. Limewater is colourless to start with If carbon dioxide is present it goes cloudy.

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17 Additives Everything in food is made of chemicals. Some foods have chemicals added to them. These are known as ADDITIVES. There are four main types, each does a different job. What do they do?

18 Antioxidants I carried out an experiment to see what chemicals could stop an apple from browning. The results are shown below. The chemicals are called antioxidants. Lemon juice Candessence Triple C Vitamin C Nothing Some chemicals work better than others as antioxidants.

19 Additives Link the additive to its function. Antioxidants Keeps ingredients mixed together Colouring Stops food from reacting with oxygen and becoming rancid Emulsifiers Helps to improve the taste of food Flavours Makes food look better and appealing

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22 Solutions- WHY? When two different liquids come together they mix and we form a solution. They are said to be miscible, an example of this would be Ribena and water.

23 Oil and Water Oil and water don t mix. We say they are immiscible. There is a definite layer between them Even when they are shaken they separate out again.

24 KEY WORDS Two liquids that DO NOT mix are called IMMISCIBLE A mixture made from 2 or more immiscible liquids is called an EMULSION.

25 Mixing oil and water with mustard Conclusion: Oil and water do not naturally mix. When we added the mustard powder we found out that they do. This is an example of how you make an emulsion. The mustard powder acts as an EMULSIFIER.

26 Making Mayonnaise In mayonnaise the egg yolk acts as the emulsifier.

27 How do emulsifiers work Hydrophilic- Hydrophobic- Water hating which attaches itself to the oil in the mixture. To help you remember: hydro= water and phobic=fear like phobia Water loving, this attaches itself to the water molecules in the mixture. The hydrophilic 'head' dissolves in the water and the hydrophobic 'tail' dissolves in the oil. In this way, the water and oil droplets become unable to separate out. The mixture formed is called an emulsion. Oil Water

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30 Dissolving Some substances cannot dissolve and are insoluble. Other substances do dissolve - they mix completely with a liquid such as water to form a mixture. Dissolving is a physical change that can be reversed.

31 Seven S Words (keep it clean).. Soluble - substances that can dissolve are soluble. Solution - the mixture formed when a substance dissolves is called the solution. Solute - a solid that dissolves is called the solute.

32 Solvent Seven S Words.. - a liquid that can dissolve a substance is the solvent. Saturated - when no more solute will dissolve in the solvent, we have a saturated solution.

33 Sediment Seven S Words.. - at the bottom of a saturated solution there can be a layer of undissolved solute called the sediment. Solubility - the amount of solute that can dissolve in a litre of solvent.

34 Particles When a solute dissolves, its particles become completely mixed with the solvent particles. The mass of the solution is the same as the mass of the solute and solvent added together. This is because the solute particles are still present, even though we may no longer see the solute itself. For example, if 1g of table salt dissolves in 100g of water, the mass of the solution is: 1g + 100g = 101g.

35 Smell: What is an ester? Esters are chemicals with pleasant smells. They are used in perfumes, as solvents and flavourings

36 Making esters Esters occur naturally, but can be made in the laboratory by reacting an alcohol with an organic acid A little sulfuric acid is needed as a catalyst. word equation: alcohol + organic acid ester + water For example: methanol + butanoic methyl + water acid butanoate

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38 Perfumes Perfumes have a pleasant smell they stimulate sense cells in the nose. Some perfumes are obtained from natural sources, such as lavender oil or sandalwood oil. Others are made synthetically (in the lab).

39 What properties do perfumes need to be successful?

40 Why are perfumes volatile? Volatile liquids evaporate easily. They readily change from a liquid to a gas. This is because there are only weak attractive forces between particles in the substance. These forces are overcome easily, so particles with enough energy can escape from the liquid.

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43 An opinion on testing cosmetics on animals!! arch

44 Why do cosmetics need to be tested? So that they do not cause harm to humans They must not cause rashes or itchiness They must not cause skin damage or lead to cancer or other lifethreatening conditions in long-term use Testing may take many years

45 What are the objections to cosmetics being tested on animals? Animals may be harmed. Animals have no control over what happens to them. Some people believe that there are other ways of testing products that are less damaging to living things.

46 What are the objections to cosmetics being tested on animals? Chemicals can have different effects on different species, e.g. bleach causes severe irritation to human skin, but only mild irritation to rabbit skin. Testing on animals can only let scientists predict what effects a product or ingredient will have on humans.

47 Some people support animal testing on cosmetics.what are their reasons? They feel safer if the cosmetics have been tested on animals. An animal s reaction to a chemical closely mimics the reaction in a human. If there is no danger to the animal then it is likely that the cosmetic or perfume will be safe for use by people.

48 Hydrocarbons Hydrogen Carbon A molecule containing only jjjjhydrogen and carbon

49 Alkanes Alkanes have the general formula: C n H 2n+2 Alkanes are SATURATED hydrocarbons. This means that they contain only single covalent bonds between carbon atoms. Each carbon has 4 bonds Each hydrogen one bond C 2 H 6 C 3 H 8

50 Covalently bonded together Single bond H H H H C C C H H H H REMEMBER it is the sharing of electrons.

51 Name Formula Displayed formula Methane Ethane CH 4 C 2 H 6 Propane C 3 H 8 Butane C 4 H 10 Pentane Hexane C 5 H 12 C 6 H 14

52 Remembering the order 1 Methane 2Ethane 3Propane 4Butane 5Pentane 6Hexane My Easy Problem Breaks Pete s Head Learn these. Remember alkenes have the ending ene

53 Alkenes Alkenes have the general formula: C n H 2n Alkenes are UNSATURATED hydrocarbons. This means that they contain at least one double bond between carbon atoms. Each carbon has 4 bonds Each hydrogen one bond C 2 H 4 C 3 H 6

54 Covalently bonded together Double bond H H C C C H H H H REMEMBER alkenes have less hydrogen due to this double bond. Single bond

55 Name Formula Displayed formula Ethene Propene C 2 H 4 C 3 H 6 Butene C 4 H 8 Pentene C 5 H 10 Hexene C 6 H 12

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58 Testing for unsaturated hydrocarbons You can tell the difference between an alkane and alkene by adding bromine water to the substance and giving the tube a shake. Alkane - the bromine water stays orange (red-brown). Alkenes the bromine water will turn colourlesss, this is because the bromine has reacted with the alkene.

59 Testing for unsaturated hydrocarbons Bromine water Alkane Alkene Alkane Alkene H H C C H H Unsaturated alkene + Br-Br Br Addition reaction H Has reacted with the bromine H C C Br H H dibromoalkane

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62 What is crude oil? Crude oil is a fossil fuel 1. Name two other fossil fuels; Coal and gas Fossil fuels are non renewable. 2. What is meant by non renewable? Something that takes along time to make and is used up faster than it is made. It will run out one day.

63 What do we use crude oil for? Petrol & diesel Fuel Plastics Drugs

64 Crude oil It is a mixture of hydrocarbons, all of which have different boiling points. Can you name any of them? = Hydrogen =Carbon

65 Explaining boiling point Covalent bonds Intermolecular forces Intermolecular forces In a liquid hydrocarbon there are two forces acting at the same time: 1. Covalent bonds (between atoms) 2. Intermolecular forces (between molecules) During boiling it is the intermolecular forces that are broken because these are weaker than the covalent bonds.

66 Which has the highest boiling point, long or short chain hydrocarbons? Intermolecular forces 6 Intermolecular forces to break to make it boil 2 Intermolecular forces to break to make it boil The longer chain hydrocarbon has the higher boiling point because the intermolecular forces are stronger between long chain hydrocarbons compared to short chain hydrocarbons.

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71 C 1 C 4 To separate crude 20 C oil; a mixture LPG of hydrocarbons, all with different boiling points, C 5 C 9 we use fractional distillation. Petrol 70 C C 5 C C Fractional distillation Naphtha heated Crude oil C 10 C C C 14 C C C 20 C C C 30 C C > C 70 Kerosine / paraffin Diesel lubricating oils, waxes, polishes Fuel oil Bitumen

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74 Cracking

75 Percentage of total Why do we need to crack molecules? demand supply supply supply supply demand demand demand demand supply LPG Petrol Kerosine Diesel Residue We have too many long chain molecules and not enough short chain ones. Supply must meet demand

76 Catalytic Cracking Large hydrocarbons are broken into smaller molecules using heat and a catalyst. This process is known as catalytic cracking. The small molecules produced are then separated by distillation. pressure Distillation tower Big Molecules Heat to vaporise Catalytic cracker Molecules break up

77 Catalytic Cracking In the catalytic cracker long chain molecules are split apart or cracked. H H H H H H H H H C C C C C C C C H H H H H H H H H Octane

78 Catalytic Cracking In the catalytic cracker long chain molecules are split apart or cracked. H H C H C H H H H C C C C H H C C H H H H H H H H H Hexane Ethene shorter chain hydrocarbon alkene C 8 H 18 C 6 H 14 + C 2 H 4 We always make an alkene and an alkane.

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83 Some Terms Polymers are materials made from very large molecules. Types of polymers include plastics, rubbers, and gels. When a plastic is stretched or pressed, the change is permanent. After a rubber is stretched, it can return to its original size and shape. This deformation is elastic. Plastic cup Rubber balloons

84 What is a polymer? Polymer has a Greek origin: poly = many mer = parts mono = one A polymer consists of many monomers joined to make a long chain. Each chemical group is like a bead in a necklace.

85 vinyl chloride Double bond opens up repeat unit repeat unit Then molecules join together repeat unit etc etc poly(vinyl chloride)

86 POLYMERISATION Copy and complete the following Plastics are made from large molecules called. polymers Each of these molecules are made from many small molecules called. monomers This type of reaction is called, addition polymerisation and requires high temperature and a catalyst. monomers temperature polymers addition polymerisation Poly-parrot?

87 Naming Monomers and Polymers Copy and complete the following table. MONOMER ethene propene styrene vinyl chloride Tetrafluoroethene POLYMER Poly(ethene) poly(propene) Poly(styrene) poly(vinyl chloride) Poly (tetrafluoroethene)

88 Drawing polymers shorthand formulae Polymers contain thousands of atoms, so how can their structures be easily drawn? Part of the polymer molecule can be drawn: A better way is to show a shorthand formula: The n means that the polymer contains a very large number of the repeating unit shown in the brackets.

89 What s the polymer? What is the shorthand formula for polypropene? The monomer is propene (C 3 H 6 ): which can be drawn as: 1. Draw two C atoms that were in the double bond with a single covalent bond. 2. Add the atoms that were attached to each C atom of the double bond. 3. Add the links outside the brackets. 4. Draw the brackets and the n. poly(propene)

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92 Flexible Waterproof Shatterproof Light Properties of Plastics Why might you want something to have these properties? Write an explanation for each one. you can squeeze the contents out of the bottle the container will not leak the object won t break if dropped easy and cheap to transport Easily moulded can make plastic into complicated shapes Heat insulators cool to touch when contains something hot Durable -will last for a long time Electrical insulators electricity won t pass through, so it s safe to handle Resistant to chemicals -won t react with chemicals

93 Properties and uses Nylon; Coats used for hill walking need to be water proof but light weight. The table below shows the properties of nylon showing it s a good polymer to use to make coats. Polymer Property 1 Property 2 Property 3 Property 4 Property 5 Nylon Tough Lightweight Keeps water out Keeps UV light out Flexible thread Try to think of 3 properties you want a polymer to have for the uses of the objects below. Rope Drain pipe Hot drink cup Property 1 Property 2 Property 3

94 Explaining properties of plastics? THERMOPLASTIC Weak intermolecular forces between the polymer molecules. These plastics have low melting points. These plastics can be easily stretched as the polymer molecules can slide over one another and are usually flexible Strong forces between the polymer molecules (covalent bond or cross links). Theses plastics have high melting points. These plastics cannot be easily stretched as the molecules cannot slide over one another These plastics are usually. rigid THERMOSETTING

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96 How does gore-tex work? Water vapour (sweat) body moisture Wind/rain Outer material GORE-TEX membrane Lining material

97 How does gore-tex work 2? Rain Wind Outer material Body moisture GORE-TEX membrane

98 Gore-tex membrane SKIN Gore-tex; Has millions of tiny holes in it. Rain water; Won t fit through the holes. Sweat; Will fit through the holes.

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102 What do we mean by biodegradable? Capable of being broken down or decomposed by natural biological processes. Most plastics do not break down naturally- they are non biodegradable.

103 Plastic code Type of plastic polymer Types of polymers Properties Common packaging application Picture Polyethylene, terephalate (PET, PETE) Clarity, strength, toughness, barrier to gas and moisture. Soft drink, water and salad dressing bottles, peanut butter and jam jars High Density polyethylene Stiffness, strength, toughness, resistance to moisture, permeability to gas. Milk, juice and water bottles, rubbish and retail bags. Polyvinyl chloride Versatility, clarity, ease of blending, strength, toughness. Juice bottles, cling films and PVC piping Low density polyethylene Ease of processing strength, toughness, flexibility, ease of sealing, barrier to moisture. Frozen food bags, squeezable bottles, eg. Honey, mustard, cling films, flexible container lids.

104 Plastic code Type of plastic polymer Types of polymers Properties Common packaging application Picture Polypropylene Polystyrene Strength, toughness, resistance to heat, chemicals, grease and oil, versatile, barrier to moisture. Versatility, clarity, easily formed. Reusable microwave ware, yoghurt containers, margarine tubs, microwave disposable takeaway containers, disposable cutlery. Disposable cups and plates, packaging material Other (often polycarbonate) Dependant on polymers or combination of polymers Beverage bottles, baby milk bottles, electronic casing.

105 Disposal of plastics 1) Landfill sites - most plastics do not which means that landfill sites are quickly filled up. Research is being carried out on plastics. 2) Burning this releases carbon dioxide which causes the effect, as well as other gases. 3) the best option, but difficult because of the different types of plastic Words recycling, greenhouse, decompose, biodegradable, poisonous

106 Different of plastics types cannot be mixed when they are recycled. Here are some of the products made from recycled plastics. Recycling Plastics

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109 T oxicity Picking the right fuel -how poisonous is the fuel. E A C U P S nergy value vailability ost sability ollution torage -how much energy the fuel gives out. -how easy the fuel is to get hold of. -how expensive the fuel is. -how easy the fuel is to use. -how pollution the fuel creates. -easy the fuel is to store.

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114 Definitions Fuel A substance that releases energy when burnt Combustion A chemical reaction; when a substance combines with oxygen and releases energy How many fuels can you list?

115 The Tests? Lime Water Limewater is the common name for a saturated solution of calcium hydroxide Clear, colourless limewater absorbs carbon dioxide readily from air, giving a milky solution. This is due to the insoluble suspension of calcium carbonate formed: Cobalt Chloride Paper Water or its vapour will turn cobalt chloride paper from blue to pink. Water or its vapour turns anhydro us copper(ii) sulphate c rystals from white to blue. Water melts at 0 C and boils at 100 C. Ca(OH) 2 (aq) + CO 2 (g) CaCO 3 (s) + H 2 O(l)

116 REACTANTS PRODUCTS Combustion is the reaction between a fuel and oxygen These are the reactants carbon dioxide and water are made These are the products fuel + oxygen carbon dioxide + water Write word equations for the following fuels: 1.methane 2. propane 3. petrol 4. candle wax

117 Word equations Methane oxygen carbon dioxide water Propane oxygen carbon dioxide water Petrol oxygen carbon dioxide water Candle wax oxygen carbon dioxide water

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120 Carbon monoxide and dioxide, what the difference? O C O C O Carbon Dioxide Di= two Carbon monoxide Mon= one Carbon monoxide is a poisonous gas with no smell. It kills on average 40 people a year*. *

121 Combustion Lots of oxygen: Complete combustion Methane + Oxygen Carbon + Water dioxide Some oxygen: Incomplete combustion Methane + Oxygen Carbon + Water monoxide Little oxygen: Incomplete combustion Methane + Oxygen Carbon + Water

122 Lots of oxygen: Complete combustion H H C H H O O O O O CH 4 + 2O 2 CO 2 + 2H 2 O C O H H O O H H Some oxygen: H H C H H O O O C O H H O O H H Incomplete combustion CH 4 + 1½O 2 CO + 2H 2 O Little oxygen: Incomplete combustion H H C H H CH 4 + O O 2 O C C + H H O O 2H 2 O H H

123 Advances in paints What might we want a paint to do? 1. Fire proof 2. Water based 3. Infinite colours 4. Easy clean 5. Single coat 6. Rapid drying 7. Conducting 8. Magnetic 9. Glow in the dark 10. What uses do they have?

124 What is paint? Paint is a colloid- What does this mean? Solid particles are mixed and dispersed with particles of a liquid but are not dissolved. The particles are small enough so that the particles don t drop to the bottom of the liquid.

125 Solvent What do the ingredients in paint do? In a paint this is the liquid that suspends the other ingredients so it can be applied to a surface. It evaporates quickly so that the paint dries. Binding medium- This ensures that the paint adheres (sticks) to the surface, otherwise it would peel off. Pigment This is the colour in the paint. It is normally insoluble, suspended in the solvent.

126 How do paints dry? For all but a few paints to dry the solvent must evaporate. Oil Paint For an oil paint to dry, the solvent does not evaporate, instead it must undergo oxidation. What do you think this process involves? Emulsions paint- the solvent is water. What must happen for this paint to dry?

127 How do paints dry?

128 Thermochromic paints Paints which change colour with a change in temperature. Write some possible uses of thermochromic pigments.

129 Phosphorescent pigments Phosphorescent pigments absorb and store energy and release it as light over a period of time. What are the uses of phosphorescent pigments?

130 Choose a watch... carefully radium watch c.1950 half life 1600 extremely radioactive phosphorescent watchphosphorescent paint, no radiation tritium watch- Ok, half life 12 years not very dangerous won t get through glass or top layer of skin low energy Ref;

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133 What is the composition of clean air? Gas % Nitrogen 78 Oxygen 21 Carbon dioxide Other <1

134 1 The carbon cycle Name of process Gas Made Gas used up 1 Combustion Carbon dioxide Oxygen 2 Respiration Carbon dioxide Oxygen 3 4 Respiration Photosynthesis Carbon dioxide Oxygen Oxygen Carbon dioxide

135 Upsetting the balance Until recently, the environment has maintained a balance of carbon dioxide: Carbon dioxide is produced by respiration and used by photosynthesis Unfortunately, this balance is being upset by two main factors: 1) Excessive burning of fossil fuels is producing too much carbon dioxide 2) Large scale deforestation is slowing down the removal of carbon dioxide from the atmosphere

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139 In the beginning - The Earth was formed about 4500 million years ago. The very first atmosphere mainly consisted of hydrogen and helium gases. Frozen giant planets like Saturn and Jupiter still have atmospheres like this but on the warmer, smaller Earth these light gases were largely lost into space. Jupiter Saturn

140 The early atmosphere During the first billion years on Earth there was intense volcanic activity. This produced the next early atmosphere. It would have contained large quantities of carbon dioxide (CO 2 ), along with methane (CH 4 ), and ammonia (NH 3 ). This is rather like the atmosphere on Mars and Venus today. The Earth s atmosphere would also have contained water vapour which condensed to form the oceans. Mars Venus

141 Oxygen levels increase Carbon dioxide reacted with rocks and much became trapped in them. The evolution of algae some 3000 million years ago, and subsequently plants which successfully colonised the Earth s surface, led us towards the present atmosphere. Their photosynthesis replaced carbon dioxide with oxygen. Over a period of time billions of tonnes of carbon dioxide became locked up in fossil fuels. Earth Photosynthesis increased oxygen levels

142 Nitrogen makes an appearance As oxygen levels rose atmospheric ammonia (NH 3 ) reacted with oxygen(o 2 ) to form water(h 2 O) and nitrogen (N 2 ) Also, living organisms, including denitrifying bacteria, broke down nitrogen compounds releasing more nitrogen into the atmosphere. Nitrogen is inert so remains constant. And so the atmosphere headed towards a composition that has remained fairly constant for the last 200 million years. 21% 1% 78% Nitrogen Oxygen Other

143 Forming the atmosphere Lots of volcanic eruption, releasing CO 2, NH 3, CH 4 and H 2 0 [Degassing] Earth cools and water condenses forming oceans Some CO 2 trapped in rocks and later fossil fuels Algae and plants begin to evolve and grow, turning CO 2 into O 2 [Photosynthesis] O 2 + NH 3 H 2 O + N Earths present atmosphere, 2 with constant amounts of nitrogen and oxygen As O 2 levels increase this reacts with NH 3 forming H 2 O and N 2 Bacteria + legumes turn nitrogen compounds into inert N 2 gas.

144 Summary Volcanoes Algae Plants 4500 million 3000 million 2000 million 1000 million 500 million 200 million Now No gases CO 2 NH 3 CH 4 O 2 N 2 All positions are approximate

145 Tuesday, February 24, 2015 Air pollution Objectives 1. Know how air pollutants are formed & their effects. 2. Know how atmospheric pollution is controlled.

146 Polluting gases; Carbon monoxide (CO) Problem; A poisonous gas with no smell Source; incomplete combustion of petrol or diesel in car engines

147 Polluting gases; Oxides of nitrogen (NO x ) In car engine: O2+N2 2NO Problem; Causes photo chemical smog and acid rain Source; Formed in the engine of a car. The high temperatures provide the right conditions for nitrogen to react with oxygen

148 Photo chemical smog Nitrogen dioxide and various hydrocarbons produced through combustion will interact with sunlight to break down into hazardous chemicals. It doesn't have to be sunny for photochemical smog to form; UV light can also penetrate clouds. The pollutants released through human activity in this situation are known as primary pollutants, and they include sulfur dioxide, carbon monoxide, and other volatile organic compounds. When these compounds interact with the sun, they form secondary pollutants like ozone and additional hydrocarbons.

149 Polluting gases; Sulphur dioxide Problem; Acid rain Source; Formed when the impurities in the fossil fuel are burnt

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151 Acid Rain

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153 Summary Photochemical smog Oxides of nitrogen from petrol engines Acid Rain Sulphur in fossil fuels coal and oil Oxides of nitrogen from petrol engines Carbon monoxide Incomplete combustion of petrol and diesel in cars, lorries and buses

154 Catalytic converters They are used to remove the carbon monoxide in exhaust fumes, changing it to carbon dioxide 2 CO + 2 NO N CO 2

155 Can we get rid of the sulphur? Yes we use scrubbers SO 2 + CaCO 3 CaSO 4 + CO

156 Air pollution Pollution is caused by the activity of human beings. Even small amounts of can pollution ruin growing, crops corrode and metal erode carved. stonework Incomplete combustion may produce carbon monoxide gas, which is poisonous. Fossil fuels contain traces of sulphur, which are given off during as combustion sulphur dioxide. When sulphur dioxide dissolves in water, it makes the water. acidic Acid rain is rain that has sulphur dioxide dissolved in it. Acid rain can fall very close to the factory where the fuel was burned or many miles away. Acid rain created in the North of England can fall on Newcastle or can be carried on the wind and ruin trees in. Norway Photochemical smog, however, normally occurs closer to where it was produced, whether that is Los Angeles or Athens. Photochemical smog is caused by sulphur dioxide and nitrogen oxides. This can trigger severe asthma in many people acidic metals asthma Norway carbon monoxide pollution combustion stonework crops sulphur dioxide

157 Air pollution from cars e) What damage does this problem do? Causes asthma; erodes stones buildings and statues; kills plants and fish 1. In a car engine, the fuel burns with oxygen in the air. The temperature is so high that this triggers more reactions. One part of the air, which doesn t normally react, starts to react with another part of the air a) Which part of the air doesn t normally react? Nitrogen b) Name the pollutant formed. Oxides of nitrogen NO x c) Give the word equation for the formation of this pollutant Nitrogen + oxygen oxides of nitrogen d) What environmental problem does this pollutant cause? Photochemical smog: acid rain

158 Air pollution from cars Some hydrocarbon molecules in petrol don t burn completely. 2. a) Name the pollutant formed Carbon monoxide b) Give the word equation for the formation of this pollutant. Hydrocarbon + oxygen carbon monoxide + water c) What damage does this pollutant do? It is a poisonous gas

159 Air pollution from cars Fuels such as petrol contain tiny amounts of an impurity. When the fuels burns, the impurity burns as well a) Name the pollutant formed Sulphur dioxide b) Give the word equation for the formation of this pollutant Sulphur + oxygen sulphur dioxide c) What environmental problem does this pollutant cause? Acid rain d) What damage dos this problem do? Erodes stone buildings and statues; kills plants and fish