1. C1 Fractional distillation Cracking Burning fuels History of the atmosphere Air pollution Polymers Cooking and baking Perfumes and nail varnish Paints Alkanes and alkenes Go to C1Go to C2Go to C3

2. Alkanes and alkenes Hydrocarbons contain carbon and hydrogen ONLY Alkanes (C n H 2n-2 ) contain only single bonds. (saturated) Hydrocarbons contain carbon and hydrogen ONLY Alkanes (C n H 2n-2 ) contain only single bonds. (saturated) Orange bromine water goes colourless when shaken up with alkenes Alkenes (C n H 2n ) contain at least one C=C double bond. (unsaturated) Methane 1 Ethane 2 Propane 3 Butane 4 Pentane 5 Hexane 6 Methane 1 Ethane 2 Propane 3 Butane 4 Pentane 5 Hexane 6 Monkeys Eat Purple Bananas Pickled in Honey Monkeys Eat Purple Bananas Pickled in Honey HOME Go to C1Go to C2Go to C3

3. Fractional distillation Separates hydrocarbon fractions because they have different boiling points. Longer chains have higher boiling points because they have stronger forces between molecules. The column is hotter at the top than the bottom The crude oil is heated to a gas. As the column cools the gas rises. When the temperature drops below a substances boiling point, it becomes a liquid and is separated off. Separates hydrocarbon fractions because they have different boiling points. Longer chains have higher boiling points because they have stronger forces between molecules. The column is hotter at the top than the bottom The crude oil is heated to a gas. As the column cools the gas rises. When the temperature drops below a substances boiling point, it becomes a liquid and is separated off. LPG Petrol Naptha Kerosene Diesel Lubricating oil Fuel oil Bitumen Cool Crude oil in hot HOME Go to C1Go to C2Go to C3

4. Cracking Breaking down long chain hydrocarbons into short chain ones. Needs heat and a catalyst. Supply and demand A big supply of long chain (e.g. fuel oil) A small supply of short chain (e.g. petrol) We need more petrol than the supply… so we ‘crack’ fuel oil which has more supply than demand. Breaking down long chain hydrocarbons into short chain ones. Needs heat and a catalyst. Supply and demand A big supply of long chain (e.g. fuel oil) A small supply of short chain (e.g. petrol) We need more petrol than the supply… so we ‘crack’ fuel oil which has more supply than demand. When cracking long hydrocarbons we produce a smaller alkane and an alkene. Fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst. This breaks chemical bonds in the molecules, and forms smaller hydrocarbon molecules. Cracking is an example of a thermal decomposition reaction Fractions containing large hydrocarbon molecules are vaporised and passed over a hot catalyst. This breaks chemical bonds in the molecules, and forms smaller hydrocarbon molecules. Cracking is an example of a thermal decomposition reaction HOME Go to C1Go to C2Go to C3

5. Fuels Plenty of oxygen Less oxygen Very little oxygen Plenty of oxygen Less oxygen Very little oxygen Complete combustion Releases LOTS of energy Blue flame Complete combustion Releases LOTS of energy Blue flame Incomplete combustion Releases some energy Yellow flame Soot Incomplete combustion Releases some energy Yellow flame Soot For the exam you must be able to WRITE AND BALANCE they symbol equations for each of these HOME Go to C1Go to C2Go to C3

6. History of atmosphere -v- today Chemical reaction between rocks and ammonia produce nitrogen and water. The water gradually condensed to make the oceans. There is very little carbon dioxide left now – it’s JUST RIGHT There is very little carbon dioxide left now – it’s JUST RIGHT The protection of the ozone layer meant animals evolved The protection of the ozone layer meant animals evolved Oxygen reacted to make the ozone layer which protects us from the Sun Oxygen reacted to make the ozone layer which protects us from the Sun The early atmosphere was made of ammonia and later carbon dioxide. Volcanoes give out steam and carbon dioxide, this was called degassing Carbon dioxide was dissolved into the sea but nitrogen remained (because it is unreactive) Plants evolved. Photosynthesis used up carbon dioxide to produce oxygen. Carbon dioxide was dissolved into the sea but nitrogen remained (because it is unreactive) Plants evolved. Photosynthesis used up carbon dioxide to produce oxygen. HOME Go to C1Go to C2Go to C3

7. Air pollution 3 main pollutants – Sulphur dioxide – side product from burning fossil fuels – Nitrogen oxides – made in vehicle engines as nitrogen and oxygen from the air react in the hot temperatures. – Carbon monoxide – from incomplete combustion Problems: – sulphur dioxide and nitrogen oxides form acid rain. – Acid rain can damage buildings and kill trees and animals (over time). – Carbon monoxide is poisonous. 3 main pollutants – Sulphur dioxide – side product from burning fossil fuels – Nitrogen oxides – made in vehicle engines as nitrogen and oxygen from the air react in the hot temperatures. – Carbon monoxide – from incomplete combustion Problems: – sulphur dioxide and nitrogen oxides form acid rain. – Acid rain can damage buildings and kill trees and animals (over time). – Carbon monoxide is poisonous. Catalytic converters use a platinum and rhodium catalyst with a high surface area. This increases the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air. The product from this is carbon dioxide and water, which is less harmful to the environment. The catalysts are designed to work best at the high temperatures found in the engine. HOME Go to C1Go to C2Go to C3

8. Polymers Alkenes can react together to make a polymer. A polymer is a very long chain molecule made from repeating units (monomers). monomer polymer MonomerPolymer EthenePolyethene PropenePolypropene StyrenePolystyrene TetrafluroethenePolytetrafluroethene (PTFE) You need to match the properties to the use. e.g. waterproof - drainpipes You need to match the properties to the use. e.g. waterproof - drainpipes Polymers are made when monomers are joined together in polymerisation. The double bond is broken and the monomers joined together. In this the molecules go from being unsaturated to saturated. Polymers are made when monomers are joined together in polymerisation. The double bond is broken and the monomers joined together. In this the molecules go from being unsaturated to saturated. Written formula = Name. This is always Poly(name of monomer) Eg. Ethene = poly(ethane). Always named after the alkene Displayed formula = bonding and atoms drawn. Smallest repeating unit is drawn in square brackets The small n shows there could be more repeats Written formula = Name. This is always Poly(name of monomer) Eg. Ethene = poly(ethane). Always named after the alkene Displayed formula = bonding and atoms drawn. Smallest repeating unit is drawn in square brackets The small n shows there could be more repeats HOME Go to C1Go to C2Go to C3

9. Cooking and baking Why we cook: – Improves taste and texture – Kills bacteria – Neutralises certain toxins Why we cook: – Improves taste and texture – Kills bacteria – Neutralises certain toxins Thermal decomposition of baking powder: Sodium hydrogen carbonate → sodium carbonate + carbon dioxide + water 2 NaHCO 3 → Na 2 CO 3 + CO 2 + H 2 O Thermal decomposition of baking powder: Sodium hydrogen carbonate → sodium carbonate + carbon dioxide + water 2 NaHCO 3 → Na 2 CO 3 + CO 2 + H 2 O During cooking proteins are denatured. This is the changing of shape of the protein which occurs in the protein molecule. This is irreversible. Emulsions Emulsions are mixtures of compounds which do not usually mix but are held together by an emulsifier. Mayonnaise is an example. The emulsifier is egg. The egg white has a hydrophobic (water hating) and hydrophilic (water loving) end. The hydrophilic end will attract water, whilst the hydrophobic end attracts oil. Mixing the two molecules to make mayonnaise. Emulsions Emulsions are mixtures of compounds which do not usually mix but are held together by an emulsifier. Mayonnaise is an example. The emulsifier is egg. The egg white has a hydrophobic (water hating) and hydrophilic (water loving) end. The hydrophilic end will attract water, whilst the hydrophobic end attracts oil. Mixing the two molecules to make mayonnaise. HOME Go to C1Go to C2Go to C3

10. Perfumes and nail varnish A good perfume should: – Evaporate easily (volatile) – Be waterproof – Not react with water – Be non-toxic – Not irritate the skin A good perfume should: – Evaporate easily (volatile) – Be waterproof – Not react with water – Be non-toxic – Not irritate the skin Nail varnish -v- solutions Solvent: Solute: solution: Dissolving depends on forces…… If solvent-substance forces are bigger than solvent-solvent or substance-substance forces, then the substance will dissolve. Nail varnish -v- solutions Solvent: Solute: solution: Dissolving depends on forces…… If solvent-substance forces are bigger than solvent-solvent or substance-substance forces, then the substance will dissolve. ethanol + ethanoic acid  ethyl ethanoate C 2 H 5 OH + CH 3 COOH  CH 3 COOC 2 H 5 ethanol + ethanoic acid  ethyl ethanoate C 2 H 5 OH + CH 3 COOH  CH 3 COOC 2 H 5 Esters are chemicals that have nice smells. Esters are made from heating alcohols with acid Alcohol + acid → ester + water Esters are chemicals that have nice smells. Esters are made from heating alcohols with acid Alcohol + acid → ester + water If a liquid is volatile it will evaporate quickly. Particles in a volatile liquid will move very quickly. Because there is only a weak attraction between molecules so these are easily overcome. The particles can escape the surface (breaking force of attraction) and become gas- this is what we smell If a liquid is volatile it will evaporate quickly. Particles in a volatile liquid will move very quickly. Because there is only a weak attraction between molecules so these are easily overcome. The particles can escape the surface (breaking force of attraction) and become gas- this is what we smell HOME Go to C1Go to C2Go to C3

11. Paints Used for: – Protection – Decoration Made of: – Pigment – Binder – Solvent Applied in a thin layer. Solvent evaporates leaving the pigment and binder stuck to the wall. Used for: – Protection – Decoration Made of: – Pigment – Binder – Solvent Applied in a thin layer. Solvent evaporates leaving the pigment and binder stuck to the wall. Types of paint Emulsion: pigment and binder dissolved in water. Oil paint: pigment dispersed in an oil. Solvent is something that dissolves oil. When the solvent evaporates, the oil binder react with oxygen in the air to form a tough layer. Oxidises Thermochromic: change colour when heated. There are two types: liquid crystal and Leuco dyes. Leuco dyes have a wider tange of colours and are used in novelty items where as liquid crystals are used for medical uses and precision equipment Phosphorescent: absorb light energy. Glow in the dark. The radiation they absorb is released at a low level for a long period of time. These materials contain strontium aluminate based pigments. Types of paint Emulsion: pigment and binder dissolved in water. Oil paint: pigment dispersed in an oil. Solvent is something that dissolves oil. When the solvent evaporates, the oil binder react with oxygen in the air to form a tough layer. Oxidises Thermochromic: change colour when heated. There are two types: liquid crystal and Leuco dyes. Leuco dyes have a wider tange of colours and are used in novelty items where as liquid crystals are used for medical uses and precision equipment Phosphorescent: absorb light energy. Glow in the dark. The radiation they absorb is released at a low level for a long period of time. These materials contain strontium aluminate based pigments. Colloid: a mixture that does not settle out. The particles of pigment are too small. HOME Go to C1Go to C2Go to C3

12. C2 The Structure Of The Earth Construction Materials Metals and Alloys Acids and Bases Making Ammonia Making Cars Fertilisers And Crop Yields Chemicals From The Sea Go to C1Go to C2Go to C3

13. HOME The Structure The Earth is almost a sphere. These are its main layers, starting with the outermost: crust - relatively thin and rocky mantle - has the properties of a solid, but can flow very slowly outer core - made from liquid nickel and iron inner core - made from solid nickel and iron. It is difficult to study the structure of the Earth because: the crust is too thick to drill all the way through scientists need to study seismic waves made by earthquakes or man-made explosions. Plate Tectonics Tectonic plates move very slowly relative to one another, around 2.5 cm per year. Although this doesn't sound like very much, over millions of years the movement allows whole continents to shift thousands of kilometres apart. This process is called continental drift. Where tectonic plates meet, the Earth's crust becomes unstable as the plates move. Earthquakes and volcanic eruptions happen at the boundaries between plates, and the crust may ‘crumple’ to form mountain ranges. Volcanoes Magma is molten rock under the Earth’s surface. Lava is molten rock that escapes onto the Earth’s surface, for example from a volcanic eruption. Volcanic eruptions Some eruptions produce runny lava, while others produce thick lava that escapes violently. Geologists study volcanoes to try to predict future eruptions, and to gather information about the Earth’s structure. Volcanoes can be very destructive, but some people choose to live near them because volcanic soil is very fertile which makes it better for farming. Igneous rocks Igneous rocks are made when molten rock cools down and solidifies. The slower the molten rock cools, the larger the crystals become. Different types of igneous rocks form lava (molten rock on the Earth’s surface):  basalt is rich in iron - it formed from runny lava produced in a fairly safe volcanic eruption.  rhyolite is rich in silica - it formed from thick lava produced in an explosive eruption. The Structure of the Earth The Structure The Earth is almost a sphere. These are its main layers, starting with the outermost: crust - relatively thin and rocky mantle - has the properties of a solid, but can flow very slowly outer core - made from liquid nickel and iron inner core - made from solid nickel and iron. Plate Tectonics Volcanoes Tectonic plates move very slowly relative to one another, around 2.5 cm per year. Although this doesn't sound like very much, over millions of years the movement allows whole continents to shift thousands of kilometres apart. This process is called continental drift. Where tectonic plates meet, the Earth's crust becomes unstable as the plates move. Earthquakes and volcanic eruptions happen at the boundaries between plates, and the crust may ‘crumple’ to form mountain ranges. Magma is molten rock under the Earth’s surface. Lava is molten rock that escapes onto the Earth’s surface, for example from a volcanic eruption. Volcanic eruptions Some eruptions produce runny lava, while others produce thick lava that escapes violently. Geologists study volcanoes to try to predict future eruptions, and to gather information about the Earth’s structure. Volcanoes can be very destructive, but some people choose to live near them because volcanic soil is very fertile which makes it better for farming. Igneous rocks Igneous rocks are made when molten rock cools down and solidifies. The slower the molten rock cools, the larger the crystals become. Different types of igneous rocks form lava (molten rock on the Earth’s surface):  basalt is rich in iron - it formed from runny lava produced in a fairly safe volcanic eruption.  rhyolite is rich in silica - it formed from thick lava produced in an explosive eruption. The Structure The Earth is almost a sphere. These are its main layers, starting with the outermost: crust - relatively thin and rocky mantle - has the properties of a solid, but can flow very slowly outer core - made from liquid nickel and iron inner core - made from solid nickel and iron. Plate Tectonics Volcanoes Go to C1Go to C2Go to C3

14. Rocks The materials used in the construction industry: MaterialHow it is made aluminium and ironmetals obtained from ores brickmade from clay glassmade from sand cement and concretemade using limestone granite, limestone and marble rocks mined or quarried from the ground Limestone and Marble Limestone and marble are both forms of calcium carbonate, CaCO 3. The UK’s limestone deposits are in areas of great natural beauty, and this creates environmental problems. Reactions of calcium carbonate Construction Materials Limestone and marble are mostly calcium carbonate. This breaks down when heated strongly. The reaction is called thermal decomposition. Here are the equations for the thermal decomposition of calcium carbonate: calcium carbonate calcium oxide + carbon dioxide CaCO 3 CaO + CO 2 Cement and concrete Cement and concrete are made from limestone, Cement is made by heating powdered limestone with clay. Concrete is made by mixing cement with sand, water and aggregate (crushed rock). Chemical reactions happen in the mixtures and eventually they set hard. Reinforced concrete Concrete is often reinforced with steel. A steel support is made by joining steel bars or cables together and this is then usually surrounded by a mould. Concrete is poured into the mould, where it fills the gaps in the steel support and sets hard. Reinforced concrete is an example of a composite material. Reinforced concrete is a composite material made from concrete and steel. It is a better construction material than concrete alone because:  concrete is hard and strong when squashed, but weak when stretched.  steel is flexible and strong when stretched. The composite material combines the best properties of both materials, so that it is hard and strong when squashed or stretched. This makes it useful for building bridges. HOME Go to C1Go to C2Go to C3

15. Copper Copper can be extracted from its ore by heating it with carbon. Impure copper is purified by electrolysis in which the anode is impure copper, the cathode is pure copper and the electrolyte is copper sulphate solution. An alloy is a mixture of two elements, one of which is a metal. Alloys often have more useful properties than the metals they contain. Extraction and purification of copper Copper is less reactive than carbon, so it can be extracted from its ores by heating it with carbon. For example: copper(II) oxide + carbon → copper + carbon dioxide or 2CuO + C → 2Cu + CO 2 Removing oxygen from a substance is called reduction. The copper oxide is reduced to copper in the reaction above. Electrolysis Copper is purified by electrolysis. Electricity is passed through solutions containing copper compounds, such as copper(II) sulphate. Pure copper forms on the negative electrode. Alloys An alloy is a mixture of two elements, one of which is a metal. Alloys often have properties that are different to the metals they contain. This makes them more useful than the pure metals alone. For example, alloys are often harder than the metal they contain. Alloys contain atoms of different sizes, which distorts the regular arrangements of atoms. This makes it more difficult for the layers to slide over each other, so alloys are harder than the pure metal they contain. A summary of three common alloys, the metals they contain, and their typical uses: Copper and Alloys- Higher tier Metals and Alloys Electrolysis For the purification of copper it is important that: 1.the anode (positive electrode) is made from impure copper, 2.the cathode (negative electrode) is made from pure copper, 3.the electrolyte (the solution that conducts electricity) is copper(II) sulphate solution. During electrolysis, the anode loses mass as copper dissolves, and the cathode gains mass as copper is deposited. Oxidisation Oxidation happens at the anode because electrons are lost. Reduction happens at the cathode because electrons are gained. Remember OIL RIG: Oxidation Is Loss of electrons, Reduction Is Gain of electrons. Smart Alloys Smart alloys have unusual properties. Nitinol is an alloy of nickel and titanium, and is known as a shape memory alloy. If nitinol is bent out of shape, it returns to its original shape when it is either heated or an electric current is passed through it. HOME Copper Copper can be extracted from its ore by heating it with carbon. Impure copper is purified by electrolysis in which the anode is impure copper, the cathode is pure copper and the electrolyte is copper sulphate solution. An alloy is a mixture of two elements, one of which is a metal. Alloys often have more useful properties than the metals they contain. Extraction and purification of copper Copper is less reactive than carbon, so it can be extracted from its ores by heating it with carbon. For example: copper(II) oxide + carbon → copper + carbon dioxide or 2CuO + C → 2Cu + CO 2 Removing oxygen from a substance is called reduction. The copper oxide is reduced to copper in the reaction above. Electrolysis Copper is purified by electrolysis. Electricity is passed through solutions containing copper compounds, such as copper(II) sulphate. Pure copper forms on the negative electrode. Alloys Go to C1Go to C2Go to C3

16. Acids and Bases Acids and alkalis The pH scale The chemical properties of many solutions enable them to be divided into three categories - acids, alkalis and neutral solutions. The strength of the acidity or alkalinity is expressed by the pH scale.  solutions with a pH less than 7 are acidic  solutions with a pH of 7 are neutral  solutions with a pH greater than 7 are alkaline. If universal indicator is added to a solution it changes to a colour that shows the pH of the solution. Bases and Acids Bases are substances that can react with acids and neutralise them. Bases such as metal oxides and metal hydroxides react with acids to form neutral products. Examples of bases include:  copper(II) oxide  zinc hydroxide. Neutralisation When an alkali is added to an acid the pH of the mixture rises. This is because the alkali reacts with the acid to form neutral products. The reverse situation also happens too: when an acid is added to an alkali the pH of the mixture falls. This is because the acid reacts with the alkali to form neutral products. A reaction in which acidity or alkalinity is removed is called neutralisation. A neutralisation involving an acid and a base (or alkali) always produces salt and water. Naming salts The name of the salt produced in a neutralisation reaction can be predicted. The first part of the name is ‘ammonium’ if the base used is ammonia. Otherwise, it is the name of the metal in the base. The second part of the name comes from the acid used:  chloride, if hydrochloric acid is used  nitrate, if nitric acid is used  sulphate, if sulphuric acid is used  phosphate, if phosphoric acid is used Carbonates and acids Carbonates also neutralise acids. As well as a salt and water, carbon dioxide is also produced. For example: hydrochloric acid + potassium carbonate → potassium chloride + water + carbon dioxide Neutralisation equations- Higher Ions in solution  Acids in solution contain hydrogen ions, H +.  Alkalis in solution contain hydroxide ions, OH -. Neutralisation can be written as an ionic equation: H + + OH - H 2 O Neutralisation equations You need to be able to write balanced symbol equations for neutralisation reactions between acids and bases, and between acids and carbonates. The equations will involve these acids:  hydrochloric acid, HCl  nitric acid, HNO 3  sulfuric acid, H 2 SO 4. The equations will involve these bases:  ammonia, NH 3 - in solution, this is NH 4 OH  potassium hydroxide, KOH  sodium hydroxide, NaOH  copper(II) oxide, CuO. They will involve these carbonates:  sodium carbonate, Na 2 CO 3  calcium carbonate, CaCO 3. HOME Go to C1Go to C2Go to C3

17. Ammonia Ammonia NH3 is a raw material used in the manufacture of fertilisers, explosives and cleaning fluids. It is produced using a reaction between nitrogen and hydrogen called the Haber process. Production costs are based on different factors:  the price of energy  The price of labour  The price of raw materials  The price of equipment  The rate of reaction. The raw materials for this process are:  hydrogen  Nitrogen Hydrogen is obtained by reacting natural gas with steam, or from cracking oil fractions nitrogen is obtained from the air. In the Haber process, nitrogen and hydrogen react together under these conditions:  a high temperature - about 450ºC  a high pressure  an iron catalyst. The Haber Process Manufacturing costs -Higher Factors that increase cost include:  high pressures (they increase the cost of the equipment)  high temperatures (they increase the energy costs). Factors that decrease  catalysts (they increase the rate of reaction).  recycling unreacted starting materials.  automating equipment (because fewer people need to be employed, cutting the wage bill). Economic considerations When a chemical is manufactured, the optimum conditions used are the ones that give the lowest cost. These conditions are not necessarily the ones that give the fastest reaction or highest percentage yield. For example:  the rate of reaction must be high enough to make enough product each day  the percentage yield must be high enough to make enough product each day. The Haber Process Making Ammonia HOME Ammonia Ammonia NH3 is a raw material used in the manufacture of fertilisers, explosives and cleaning fluids. It is produced using a reaction between nitrogen and hydrogen called the Haber process. Production costs are based on different factors:  the price of energy  The price of labour  The price of raw materials  The price of equipment  The rate of reaction. The raw materials for this process are:  hydrogen  Nitrogen Hydrogen is obtained by reacting natural gas with steam, or from cracking oil fractions nitrogen is obtained from the air. In the Haber process, nitrogen and hydrogen react together under these conditions:  a high temperature - about 450ºC  a high pressure  an iron catalyst. The Haber Process Go to C1Go to C2Go to C3

18. Making Cars Aluminium The main materials used in the manufacture of cars: Rusting Iron and steel rust when they come into contact with water and oxygen. Both water and oxygen are needed for rusting to occur. In the experiment below, the nail does not rust when air or water is not present. Remember that 21 per cent of the air is oxygen. Rusting is an oxidation reaction. The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust. This is the word equation for the reaction: iron + water + oxygen → hydrated iron(III) oxide Salt dissolved in water does not cause rusting, but it does speed it up, as does acid rain. Unlike iron and steel, aluminium does not rust or corrode in moist conditions. Its surface is protected by a natural layer of aluminium oxide. This prevents the metal below from coming into contact with air and oxygen. Car Bodies Most iron is converted into steel (an alloy) before being used. Compared to iron, steel is:  harder and stronger  less likely to rust. Iron versus aluminium Iron and aluminium are used to build cars. They are both malleable - they can be bent or pressed into shape. The table summarises some differences in their properties.: Aluminium :  Lighter – so better fuel economy  Does not corrode – lasts longer BUT  It is more expensive to use. Making cars and recycling them Recycling European Union law requires that at least 85 per cent of a car’s materials can be recycled, rising to 95 per cent by 2015. Recycling reduces the amount of waste, and the use of natural resources. HOME Go to C1Go to C2Go to C3

19. Nitrates or phosphates from fertilisers can cause eutrophication in water Problems if too much fertiliser is used it can pollute water supplies. It may also lead to eutrophication, a situation where there is not enough oxygen dissolved in the water for aquatic organisms to survive. HOME Most fertilisers are made by the reaction of an acid and an alkali. The table shows some examples. Fertilisers- Higher tier Eutrophication Fertilisers Fertilisers:  make crops grow faster and bigger so that crop yields are increased.  They are water-soluble minerals.  They must be able to dissolve in water so that plants can absorb them through their roots.  Fertilisers provide plants with the essential chemical elements needed for growth particularly nitrogen, phosphorus and potassium. Examples of fertilisers, their formula and the essential elements: Making fertilisers Fertilisers and Crop Yield Making a fertiliser in the lab The preparation of a fertiliser in a lab involves the following equipment:  a measuring cylinder to measure a particular volume of an alkali solution  a burette to add acid a little at a time until the alkali has been neutralised  a filter funnel to remove solid crystals of fertiliser after evaporating some of the water from the neutral fertiliser solution. To make ammonium nitrate you should be able to predict that nitric acid and ammonia will be needed. Go to C1Go to C2Go to C3

20. Chemicals from the Sea Useful substances can be obtained by the electrolysis of sodium chloride solution. Products from sodium chloride The products of the electrolysis of sodium chloride solution have important uses in the chemical industry. Hydrogen Hydrogen is used in the manufacture of ammonia and margarine (it is used to harden vegetable oils). Chlorine Chlorine is used to:  kill bacteria in drinking water and swimming pool water  make solvents  make plastics such as polyvinyl chloride (PVC)  make household bleach. Sodium hydroxide Sodium hydroxide is used to make soap and household bleach. Bleach Household bleach, sodium chlorate, is made when sodium hydroxide and chlorine react together: sodium hydroxide + chlorine → sodium chloride + water + sodium chlorate 2NaOH + Cl 2 → NaCl + H 2 O + NaClO Household bleach is used to clean and disinfect toilets, drains and kitchen surfaces. Obtaining sodium chloride Common salt is sodium chloride, NaCl. It can be made in a laboratory by the reaction of sodium with chlorine. However, it is found naturally in large amounts:  in sea water  in underground deposits Mining Salt can be mined as rock salt which is used to treat icy roads in the winter. It lowers the melting point of the ice on the roads so that it melts, even when the temperature is below 0ºC. Salt can also be mined by solution mining. This happens in Cheshire in the North West of England: 1.Water is pumped underground and into the salt deposit. 2.Salt dissolves in the water, forming a concentrated salt solution. 3. This is then pumped up to the surface ready for use by the chemical industry. Solution mining is safer than sending miners underground. Problems with mining:  can lead to subsidence. The weight of the ground above causes the ground to sink downwards and this subsidence can damage buildings and roads. Electrolysis During electrolysis:  chlorine gas forms at the anode (positive electrode)  hydrogen gas forms at the cathode (negative electrode)  a solution of sodium hydroxide forms. These products are reactive, so it is important to use inert (unreactive) materials for the electrodes. A half-equation shows you what happens at one of the electrodes during electrolysis. Electrons are shown as e –. These are the half- equations: anode: 2Cl – – 2e – → Cl2 (oxidation) cathode: 2H + + 2e – → H2 (reduction). HOME Go to C1Go to C2Go to C3

21. C3 Relative formula mass Calculating mass of products Percentage yield Atom Economy Exothermic and endothermic Heat capacity Making chemicals Allotropes Rates of reaction Go to C1Go to C2Go to C3

22. Rates of Reaction How much product is formed or how much reactants are used OVER time. Concentration Rate of reaction can be increase by increasing the concentration. As the concentration increases the particles become more crowded. This will increase the number of collisions between the reacting particles. More collision per second means more successful collisions. This will result in an increased rate of reaction. Concentration Rate of reaction can be increase by increasing the concentration. As the concentration increases the particles become more crowded. This will increase the number of collisions between the reacting particles. More collision per second means more successful collisions. This will result in an increased rate of reaction. Temperature As the temperature increases the particles gain KINETIC ENERGY (move more) and move around more quickly/ more energetic. Therefore partials will collide more frequently with more energy resulting in more collisions per second and therefore more successful collisions. Temperature As the temperature increases the particles gain KINETIC ENERGY (move more) and move around more quickly/ more energetic. Therefore partials will collide more frequently with more energy resulting in more collisions per second and therefore more successful collisions. ROR in gases Only if the reactants are gases you can increase the pressure. The reacting particles are squished together. This increases collisions frequency per second which means increased number of successful collisions and therefore increased rate of reaction. ROR in gases Only if the reactants are gases you can increase the pressure. The reacting particles are squished together. This increases collisions frequency per second which means increased number of successful collisions and therefore increased rate of reaction. HOME Go to C1Go to C2Go to C3

23. Relative formula mass Find the element in the periodic table. This is oxygen. You need the top number. Add all the numbers together. This gives you the total M r for the compound. Find the element in the periodic table. This is oxygen. You need the top number. Add all the numbers together. This gives you the total M r for the compound. O 8 16 NH 3 There are 1 nitrogen atom and 3 hydrogen that make up ammonia. Add the M r together for all 4 atoms and that give you the molecular mass for ammonia (the M r ) NH 3 There are 1 nitrogen atom and 3 hydrogen that make up ammonia. Add the M r together for all 4 atoms and that give you the molecular mass for ammonia (the M r ) The relative formula mass (M r ) of a compound is the relative atomic masses of all the elements in the compound added together. Compound nameFormula calcium carbonateCaCO 3 carbon dioxideCO 2 hydrochloric acidHCl sulfuric acidH 2 SO 4 calcium chlorideCaCl 2 magnesium chlorideMgCl 2 magnesium sulfateMgSO 4 HOME Go to C1Go to C2Go to C3

24. Calculating the mass of a product E.g. what mass of magnesium oxide is produced when 60g of magnesium is burned in air? Step 1: READ the equation: 2Mg + O 2 2MgO Step 1: READ the equation: 2Mg + O 2 2MgO Step 3: LEARN and APPLY the following 3 points: 1)48g of Mg makes 80g of MgO 2)1g of Mg makes 80/48 = 1.66g of MgO 3)60g of Mg makes 1.66 x 60 = 100g of MgO Step 3: LEARN and APPLY the following 3 points: 1)48g of Mg makes 80g of MgO 2)1g of Mg makes 80/48 = 1.66g of MgO 3)60g of Mg makes 1.66 x 60 = 100g of MgO Step 2: WORK OUT the relative formula masses (M r ): 2Mg = 2 x 24 = 48 2MgO = 2 x (24+16) = 80 Step 2: WORK OUT the relative formula masses (M r ): 2Mg = 2 x 24 = 48 2MgO = 2 x (24+16) = 80 ignore Reacting ratio 2 Mg makes 2 MgO HOME Go to C1Go to C2Go to C3

25. Percentage yield Percentage yield= actual yield x100 predicted yield 100% yield means... 0% yield means... 100% yield means... 0% yield means... we have lost no product we have lost all the product Percentage yield is a way of comparing amount of product made (actual yield) to amount expected (predicted yield) We might not get 100% yield because: HOME Go to C1Go to C2Go to C3

26. Atom economy The atom economy of a chemical reaction is a measure of the amount of starting materials that become useful products. Inefficient, wasteful processes have low atom economies, atoms are wasted not made into useful products.. The atom economy of a chemical reaction is a measure of the amount of starting materials that become useful products. Inefficient, wasteful processes have low atom economies, atoms are wasted not made into useful products.. 100% atom economy means... all atoms in the reactant have been converted to the desired product 0% yield means... we have lost all the product 100% atom economy means... all atoms in the reactant have been converted to the desired product 0% yield means... we have lost all the product Efficient processes have high atom economies, and are important for sustainable development, as they use fewer natural resources and create less waste. HOW do you know what is a useful product?? READ THE QUESTION Efficient processes have high atom economies, and are important for sustainable development, as they use fewer natural resources and create less waste. HOW do you know what is a useful product?? READ THE QUESTION HOME Go to C1Go to C2Go to C3

27. Exothermic and Endothermic The reactants start with more energy this is lost to the surroundings as heat during the reaction. The products have less energy than the reactants. For a reaction to be overall exothermic more bonds have to be formed than broken. The reactants start with more energy this is lost to the surroundings as heat during the reaction. The products have less energy than the reactants. For a reaction to be overall exothermic more bonds have to be formed than broken. Exothermic = Heat given out, reactants loose energy and the surroundings get warmer. Bond making is exothermic Endothermic= Heat taken in, reactants gain energy. Surroundings get cooler. Bond breaking is endothermic The reactants start with less energy, they gain energy from the surroundings. The products have more energy than the reactants. For a reaction to be endothermic more bonds have to broken than formed. The reactants start with less energy, they gain energy from the surroundings. The products have more energy than the reactants. For a reaction to be endothermic more bonds have to broken than formed. HOME Go to C1Go to C2Go to C3

28. Heat capacity and Fuels E=mc∆T Energy supplied (J) Mass of water (g) Specific heat capacity of water (J/g/ o C) Rise in temperature ( o C) Fuel Efficiency (J/g) Energy supplied (J) Mass of fuel burnt (g) This is: 4.2 J/g/ o C Constants (to make the experiment a fair test): Same volume of water Same calorimeter Same heating time Constants (to make the experiment a fair test): Same volume of water Same calorimeter Same heating time HOME Go to C1Go to C2Go to C3

29. Making chemicals Making chemicals Batch process Reactants put in one end and product removed at the other end; Make a product on demand and on a small scale. Fixed amount. Can be used to make a variety of products. As an when needed and easy to store until needed. Good for making drugs that have sell buy date. Easy to change the product from one to another. Reactants put in one end and product removed at the other end; Make a product on demand and on a small scale. Fixed amount. Can be used to make a variety of products. As an when needed and easy to store until needed. Good for making drugs that have sell buy date. Easy to change the product from one to another. Very labour intensive- reactor needs to be filled emptied and cleaned. Due to fact that it is labour intensive it will have high cost per tonne. Time needed for cleaning and to change product line Very labour intensive- reactor needs to be filled emptied and cleaned. Due to fact that it is labour intensive it will have high cost per tonne. Time needed for cleaning and to change product line Continuous process A continuous process is one in which reactants are fed in one end and a constant stream exists form the other; It runs 24 hours a day and is only shut down for maintenance of equipment or deep clean. Only used in well known and understood reactions. Eg the Haber process. High level of automation so few staff are required, making it cheaper per tonne of product. Takes less energy to maintain, as long as the process can be kept running. A continuous process is one in which reactants are fed in one end and a constant stream exists form the other; It runs 24 hours a day and is only shut down for maintenance of equipment or deep clean. Only used in well known and understood reactions. Eg the Haber process. High level of automation so few staff are required, making it cheaper per tonne of product. Takes less energy to maintain, as long as the process can be kept running. Disadvantages: High building set up cost for the chemical plant or factory. The sufficient if not used constantly. Disadvantages: High building set up cost for the chemical plant or factory. The sufficient if not used constantly. Ideas for new drugs come from a variety of places; Extracted from plants and other natural products (crushed to disrupt and break the cell wall to release the desired product, boil in a suitable solvent to dissolve compound, chromatography to separate and identify individual compounds) Subtly change old drugs- sometimes this is what scientist do instead of making new drug. Ideas for new drugs come from a variety of places; Extracted from plants and other natural products (crushed to disrupt and break the cell wall to release the desired product, boil in a suitable solvent to dissolve compound, chromatography to separate and identify individual compounds) Subtly change old drugs- sometimes this is what scientist do instead of making new drug. Go to C1Go to C2Go to C3

30. Allotropes Different forms of the same element in the same physical state. Meaning all forms are solid in this case but the atoms are BONDED differently. Carbon has the allotropes; Diamond Graphite Buckminsterfullerene Different forms of the same element in the same physical state. Meaning all forms are solid in this case but the atoms are BONDED differently. Carbon has the allotropes; Diamond Graphite Buckminsterfullerene Grahpite The carbon atoms are arranged in layers. Within each layer there are strong covalent bonds. (meaning high melting point). Between layers there are much weaker forces (meaning they are soft and slippery). These force are easy to break and allow you to write with a pencil. Between the layers the electron are delocalised (it is able to conduct electricity) Grahpite The carbon atoms are arranged in layers. Within each layer there are strong covalent bonds. (meaning high melting point). Between layers there are much weaker forces (meaning they are soft and slippery). These force are easy to break and allow you to write with a pencil. Between the layers the electron are delocalised (it is able to conduct electricity) Diamond Each carbon atom is held in place by four strong covalent bonds. These bonds require large amounts of energy to break. The means diamond has a high melting points and hardness. No free electrons so cannot conduct electricity. Diamond Each carbon atom is held in place by four strong covalent bonds. These bonds require large amounts of energy to break. The means diamond has a high melting points and hardness. No free electrons so cannot conduct electricity. HOME Go to C1Go to C2Go to C3