IGCSE+0653 Chemistry

IGCSE [|Flash Animations for chemistry] [|EDUCYPEDIA] - science [|Chemistry quizz and worksheets] and [|Doc Brown's detailed CHEMISTRY REVISION NOTES] from www.docbrown.info
 * //C1. The particulate nature of matter//**
 * //See P4.1 and P4.2 for details of common content. 1 Demonstrate understanding of the terms atom and molecule.//**

[|Simple distillation of ink] from www.fofweb.com/onfiles/seof/chemistry_experiments/3-06.pdf 1 set needed for demonstration 250 ml Erlenmeyer flask with a rubber stopper with a center hole of the correct size to take a delivery tube 30 cm glass delivery tube with a 120° bend 10 cm from one end small graduated cylinder stand and ring clamp beaker Anti-bumping granules black or blue/black ink
 * //C2. Experimental techniques//**
 * //1 Describe paper chromatography.//**
 * //2 Interpret simple chromatograms.//**
 * //3 Describe methods of separation and purification: filtration, crystallisation, distillation, fractional distillation.//**
 * //4 Suggest suitable purification techniques, given information about the substances involved.//**
 * [[image:http://www.wikispaces.com/i/mime/32/application/vnd.ms-powerpoint.png width="32" height="32" link="file:sciencelanguagegallery/15_separating_dyes_in_ink.ppt"]][[file:sciencelanguagegallery/15_separating_dyes_in_ink.ppt|15_separating_dyes_in_ink.ppt]] || [[image:http://www.wikispaces.com/i/mime/32/application/vnd.ms-powerpoint.png width="32" height="32"]] [[file:sciencelanguagegallery/5 Chromotagraphy.ppt|5 Chromotagraphy.ppt]] || [[image:http://www.wikispaces.com/i/mime/32/application/vnd.ms-powerpoint.png width="32" height="32" link="file:sciencelanguagegallery/6 Fractional Distillation.ppt"]] [[file:sciencelanguagegallery/6 Fractional Distillation.ppt|6 Fractional Distillation.ppt]] ||
 * //C3. atoms, elements and compounds//**
 * //3.1 Physical and chemical changes//**
 * //1 Identify physical and chemical changes, and understand the differences between them.//**
 * // 3.2 Elements, compounds and mixtures //**
 * //1 Describe the differences between elements, compounds and mixtures.//**
 * //2 Demonstrate understanding of the concepts of element, compound and mixture.//**

An ** element ** is made up of only one type of particle (atom). Eg. Copper is only made up of copper atoms. Oxygen is only made up of oxygen atoms All elements can be found in the __ Periodic __ table. All ATOMS have __ PROTONS __, __ NEUTRONS __ and __ ELECTRONS __. The periodic table tells us how many of each an atom has. An __ element __ is made up of only one type of atom.

A __ compound __ is made of 2 elements chemically bonded together. Eg. Water (2 hydrogen bonded to 1 oxygen). Common salt, is sodium(soft silvery metal) bonded to chlorine(a poisonous light greenish gas) to make Sodium Chloride. It is a pure  substance consisting of two or more different  elements that can be separated into simpler substances by chemical reactions. A compound has properties that differ from those of the elements that form it.

A __ mixture __ is made of more than two elements which are not chemically bonded together. Eg. Saltwater, rock salt, air.

A molecule is an electrically neutral group of two or more __ atoms __ held together by chemical __ bonds __. A molecule may consist of atoms of a single element, hydrogen (H2), or of different elements, water (H2O). Two or more atoms of the same or different elements that have bonded. A molecule is the smallest part of a substance that cannot be divided without a chemical change.

[|Atoms, Molecules, Elements and Compounds] Published on 15 Nov 2012


 * //3.3 atomic structure and the Periodic Table//**
 * //1 Describe the structure of an atom in terms of electrons and a nucleus containing protons and neutrons.//**
 * //2 Describe the build-up of electrons in ‘shells’ and understand the significance of the noble gas electronic structures and of valency electrons (the ideas of the distribution of electrons in s and p orbitals and in d block elements are not required).//**
 * //(A copy of the Periodic Table will be provided in Papers 2 and 4.)//**
 * // 3 State the relative charges and approximate relative masses of protons, neutrons and electrons. //**
 * // 4 Define atomic (proton) number and mass (nucleon) number. 5 Use proton number and the simple structure of atoms to explain the basis of the Periodic Table (see section C9), with special reference to the elements with proton numbers 1 to 20. (A copy of the Periodic Table will be provided in Papers 1 and 3.) //**



The elements in Group 1 of the Periodic Table are called the **alkali metals**. They form ionic compounds when they react with non-metals. Their ions have a single positive charge. For example, sodium forms sodium ions, Na+. The elements in Group 7 of the Periodic Table are called the **halogens**. They form ionic compounds when they react with metals. Their ions have a single negative charge. For example, chlorine forms chloride ions, Cl–. Cross dot diagrams: [|Examples of ionic bondings] BBC Bitesize
 * //3.4 Ions and ionic bonds//**
 * //1 Describe the formation of ions by electron loss or gain.//**
 * //2 Describe the formation of ionic bonds between elements from Groups I and VII.//**
 * // 3 Explain the formation of ionic bonds between metallic and non-metallic elements. //**
 * Ionic bondings **

The covalent bonds binding the atoms together are very **strong** but there are only very **weak** forces holding the molecules to each other (the **intermolecular** forces). Therefore, only a **low temperature** is needed to **separate** the molecules when they're melted or boiled. __ Low __ melting and boiling points Covalent compounds have no free electrons and no ions so they **don't conduct electricity**. Cross dot diagrams: [|Examples of covalent bondings] BBC Bitesize
 * //3.5 Molecules and covalent bonds//**
 * // 1 State that non-metallic elements form nonionic compounds using a different type of bonding called covalent bonding involving shared pairs of electrons. //**
 * // 2 Draw dot-and-cross diagrams to represent the sharing of electron pairs to form single covalent bonds in simple molecules, exemplified by H2, Cl2, H2O, CH4 and HCl. //**
 * // 3 Draw dot-and-cross diagrams to represent the multiple bonding in N2, C2H4 and CO2. //**
 * Covelent bondings**


 * //C4. Stoichiometry//**
 * // 1 Use the symbols of the elements to write the formulae of simple compounds. //**
 * // 2 Deduce the formula of a simple compound from the relative numbers of atoms present. //**
 * // 3 Deduce the formula of a simple compound from a model or a diagrammatic representation. //**
 * // 4 Determine the formula of an ionic compound from the charges on the ions present. //**
 * // 5 Construct and use word equations. //**
 * // 6 Construct and use symbolic equations with state symbols. 7 Deduce the balanced equation for a chemical reaction, given relevant information. //**

Complete a balanced word equation using the chemical equation of combustion of methane below. Image from [|www.middleschoolchemistry.com] [|Rules for naming compounds] from mattson.creighton.edu ||   || In a symbol equation the number of atoms on each side of the equation should balanced for each element. In an equation, the symbol of the each state(aqueous, solid, liquid, gas) should present in brackets and the oxidation state of a transiton metal in a word equation.
 * Balanding equation **
 * In the reaction, the the bonds in the methane and oxygen come apart, the atoms rearrange and then re-bond to form water and carbon dioxide.
 * The little number written at the lower right after an atom (subscript) tells how many of that atom are in the molecule.
 * The big number written in front of a molecule (coefficient) shows how many of that molecule there are.
 * All the atoms in the products come from the atoms in the reactants.
 * [[image:http://www.wikispaces.com/i/mime/32/application/vnd.ms-powerpoint.png width="32" height="32" link="file:sciencelanguagegallery/2 Chemical Formula.ppt"]]
 * Stoichiometry [|Worksheet] ** from www.chemteam.info

//**C5. Electricity and chemistry**// //**1 State that electrolysis is the chemical effect of electricity on ionic compounds, causing them to break up into simpler substances, usually elements.**// //**2 Use the terms electrode, electrolyte, anode and cathode.**// //** 3 Describe electrolysis in terms of the ions present and the reactions at the electrodes. **// //**4 Describe the electrode products, using inert electrodes, in the electrolysis of:**// //**• [|molten lead(II) bromide]**// //**• aqueous copper chloride.**// [|Electrolysis of molten compounds] from www.minichemistry.com Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them. [|Electrolysis] from BBC Bitesize Reduction of positive cations happens at the cathode. Oxidation of negative anions happens at the anode and cations at catode. Anode: 2 Cl - -> Cl 2 + 2e - Cathode: 2 H + + 2e - -> H 2 [|Electrolysis of copper sulfate solution] from www.docbrown.info/page01/ExIndChem/electrochemistry04.htm  ELECTRODE: a conductor through which electricity enters or leaves an object, substance, or region. ELECTROLYTE: a liquid or gel that contains ions and can be decomposed by electrolysis
 * // 5 Predict the products of the electrolysis of a specified binary compound in the molten state. //**
 * //[|Predicting the products of electrolysis]// from BBC Bitesize **


 * [|Inert electrode] ** is an **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">electrode **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;"> that serves only as a source or sink for electrons without playing a chemical role in the **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">electrode **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;"> reaction. Precious metals, mercury, and carbon are typically used as **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">inert electrodes **<span style="background-color: #ffffff; color: #222222; font-family: arial,sans-serif; font-size: 16px;">. from <span style="background-color: #ffffff; color: #006621; font-family: arial,sans-serif; font-size: 14px;">glossary.periodni.com/glossary.php?en=inert+electrode

[|Chemistry animation] from www.physics-chemistry-interactive-flash-animation.com [|Electrolysis of copper(II) sulfate solution] from www.rsc.org/learn-chemistry


 * **Electrolysis:** is the breakdown of a compound using electricity. ||
 * **Electrode:** is a conductor that is placed in the solution or liquid in an electrolysis experiment or in an electrochemical cell. ||
 * **Electrical conductor:** substance that conducts electricity ||
 * **Insulator:** substance that does not conduct electricity ||
 * **Electrolyte:** are compounds that conduct electricity when they are melted are dissolved in water. They contain ions which become free to move when molten or in water. ||
 * **Anode:** the electrode in an electrochemical or electrolytic cell where oxidation takes place (loss of electrons) ||
 * **Cathode**: the electrode in an electrochemical or electrolytic cell where reduction takes place (gain of electrons ||
 * **Electrolytic cell:** a cell consisting of two electrodes (anode and cathode) connected to an external DC power supply where positive and negative ions in an electrolyte or separated and discharged. Electrical energy is transferred to chemical energy. ||
 * **Electroplating:** a process of electrolysis where a metal object is coated with a layer of another metal ||

[|The electrolysis of lead (II) bromide using inert graphite electrodes Demo] from Youtube.com <span style="background-color: #ffffff; color: rgba(17,17,17,0.6); font-family: Roboto,Arial,sans-serif;">Published on 24 Feb 2012 || media type=custom key=29430313 [|Electrolysis of lead bromide] from youtube.com <span style="background-color: #ffffff; color: rgba(17,17,17,0.6); font-family: Roboto,Arial,sans-serif;">Published on 23 Sep 2012 || from <span style="background-color: #ffffff; color: #006621; font-family: arial,sans-serif; font-size: 14px;">chemistrysuzhou.wikispaces.com [|Topic 5 Electricity and chemistry - henniscience] from .weebly.com/topic-5-electricity-and-chemistry.html
 * media type=custom key=29428897

Exothermic and Endothermic Reactions from KS3 [|Endothermic or exothermic reactions] method //Apparatus and chemicals// Polystyrene cup, 250 cm 3 Beaker (used to support the polystyrene cup), Thermometer, Measuring cylinder (10 cm 3 ) and Spatula. The following solutions (all at approx 0.4 mol dm â3 concentration): Copper(II) sulfate, Hydrochloric acid, Sodium hydrogencarbonate, Sodium hydroxide, Sulfuric acid, Citric acid. Magnesium ribbon (cut into 3 cm lengths), Magnesium powder [|Mol calculation quantitative-units-of-concentration] from BC OPEN TEXTBOOKS
 * //C6. Energy changes in chemical reactions//**
 * // 1 Relate the terms exothermic and endothermic to the temperature changes observed during chemical reactions. //**
 * // 2 Demonstrate understanding that exothermic and endothermic changes relate to the transformation of chemical energy to heat (thermal energy), and vice versa. //**

(Please have the materials separated and labelled for each different experiment) CONCENTRATION 15cm Mg ribbon (cleaned please) 40ml 1M HCl 1 conical flask 10ml measuring cylinder TEMPERATURE 2 x 100cm3 beakers 50ml 0.1M sodium thiosulphate 50ml 0.5M HCl CATALYSIS 3 test tubes 10cm3 measuring cylinder pipette granulated zinc (about 12 peices) copper turnings oe powder (1g) 5ml dilute H2SO4 5ml copper sulphate 0.5M **<span style="font-family: &#39;Trebuchet MS&#39;,sans-serif; font-size: 18pt;">Marble Chips and Hydrochloroic Acid – ** **<span style="font-family: &#39;Trebuchet MS&#39;,sans-serif; font-size: 18pt;">The Weight Loss Method!! **
 * //C7. Chemical reactions//**
 * // 7.1 Rate of reaction //**
 * // 1 Describe the effect of concentration, particle size, catalysis and temperature on the rate of reaction. //**
 * // 2 Describe a practical method for investigating the rate of a reaction involving gas evolution. //**
 * // 3 Interpret data obtained from experiments concerned with rate of reaction. //**
 * // 4 Describe and explain the effects of temperature and concentration in terms of collisions between reacting particles (the concept of activation energy will not be examined). //**
 * //5 Define catalyst as an agent which increases rate of reaction but which remains unchanged.//**

<span style="font-family: &#39;Century Gothic&#39;,sans-serif;">The effect of concentration of acid or size of marble chips on the rate of a reaction can be determined by measuring the loss in mass of the marble chips. In this experiment a known mass of marble chips will be added to 1M Hydrochloric Acid as the reaction progresses and the marble chips react with the acid there will be a loss in mass. <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">You will need to weigh exactly 10 grams of calcium carbonate each time, and use 50cm3 of acid. This should mean that each trial starts at time 0 with a mass of 60 grams. <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">Diagram: <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">Record the results from this demonstration in the table below: ¨ **<span style="font-family: &#39;Century Gothic&#39;,sans-serif;">Experimental errors ** <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">Where are the experimental errors in this experiment?
 * Powder |||| Small Chips |||| Large Chips ||
 * Time (s) || Mass (g) || Time (s) || Mass (g) || Time (s) || Mass (g) ||
 * 15 ||  || 15 ||   || 15 ||   ||
 * 30 ||  || 30 ||   || 30 ||   ||
 * 45 ||  || 45 ||   || 45 ||   ||
 * 60 ||  || 60 ||   || 60 ||   ||
 * 75 ||  || 75 ||   || 75 ||   ||
 * 90 ||  || 90 ||   || 90 ||   ||
 * 105 ||  || 105 ||   || 105 ||   ||
 * 120 ||  || 120 ||   || 120 ||   ||
 * Things to Think About**


 * <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">……………………………………………………………………………………………………………………………… **


 * <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">……………………………………………………………………………………………………………………………… **

¨ **<span style="font-family: &#39;Century Gothic&#39;,sans-serif;">How does this method compare to other methods you have seen (think back to magnesium and gas production)? **


 * <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">……………………………………………………………………………………………………………………………… **


 * <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">…………………………………………………………………………………………………………………………….. **


 * <span style="font-family: &#39;Century Gothic&#39;,sans-serif;">Draw a graph from your results. Remember what is required to obtain maximum marks. **


 * ¨ **<span style="font-family: &#39;Bradley Hand ITC&#39;; font-size: 14pt;">What scale are you going to chose? **
 * ¨ **<span style="font-family: &#39;Bradley Hand ITC&#39;; font-size: 14pt;">Which axis does the time go on? **
 * ¨ **<span style="font-family: &#39;Bradley Hand ITC&#39;; font-size: 14pt;">Are your axis labelled? **
 * ¨ **<span style="font-family: &#39;Bradley Hand ITC&#39;; font-size: 14pt;">What are your units? **
 * ¨ **<span style="font-family: &#39;Bradley Hand ITC&#39;; font-size: 14pt;">How should your line of best fit be drawn? **

Rates of reaction from KS3
media type="youtube" key="NaGQ9VI5mwg" width="560" height="315" <span style="color: var(--ytd-video-primary-info-renderer-title-color,var(--yt-primary-text-color)); font-family: var(--ytd-video-primary-info-renderer-title-font-family,inherit); font-size: var(--ytd-video-primary-info-renderer-title-font-size,1.8rem);">[|Redox Reactions] <span class="view-count style-scope yt-view-count-renderer" style="color: var(--yt-metadata-color);"><span style="font-family: Roboto,Arial,sans-serif; font-size: 10px;">[|Smart Learning for All] <span style="color: var(--ytd-video-publish-date-color); font-family: Roboto,Arial,sans-serif; font-size: 1.3rem;">Published on 2 May 2015 Redox reaction is a reaction where reduction and oxidation happen, where there is electron ransfer. Reduction and oxidation must happen together. Examples) Potassium iodide goes from colourless to red-brown. It is a reducing agent and thus it is oxidised to produce I2: H2O2 + **2**K**I** + H2SO4 -> **I2** + K2SO4 + 2 H2O Potassium dichromate, an oxidising agent: Cr2O7 2- (orange) -> 2 Cr3+ (green) OIL, RIG:
 * //7.2 Redox//**
 * // 1 Define oxidation and reduction in terms of oxygen loss / gain, and identify such reactions from given information. //**
 * O**xidation **I**s **L**oss of electrons or gain of oxygen.
 * R**eduction **I**s **G**ain of electrons or loss of oxygen.


 * //C8. acids, bases and salts//**
 * // 8.1 The characteristic properties of acids and bases //**
 * // 1 Describe neutrality and relative acidity and alkalinity in terms of pH (whole numbers only) measured using full-range indicator and litmus. //**
 * // 2 Describe the characteristic reactions of acids with metals, bases (including alkalis) and carbonates. //**
 * // 3 Describe and explain the importance of controlling acidity in the environment (air, water and soil). //**

Acids and alkalis from KS3
//**8.2 Preparation of salts**// //** 1 Describe the preparation, separation and purification of salts using techniques selected from section C2.1 and the reactions specified in section C8.1. **// //** 2 Suggest a method of making a given salt from suitable starting material, given appropriate information. **//

Preparing common salts from KS3


//**8.3 Identification of ions and gases**// //** 1 Use the following tests to identify: **// //** aqueous cations: **// //** • ammonium, copper(II), iron(II), iron(III) and zinc by means of aqueous sodium hydroxide and aqueous ammonia as appropriate (formulae of complex ions are not required) **// //** anions: **// //** • carbonate by means of dilute acid and then limewater **// //** • chloride by means of aqueous silver nitrate under acidic conditions **// //** • nitrate by reduction with aluminium **// //** • sulfate by means of aqueous barium ions under acidic conditions gases: **// //** • ammonia by means of damp red litmus paper **// //** • carbon dioxide by means of limewater **// //** • chlorine by means of damp litmus paper **// //** • hydrogen by means of a lighted splint **// //** • oxygen by means of a glowing splint. **//

//**C9. The Periodic Table**// //** 1 Describe the way the Periodic Table classifies elements in order of atomic (proton) number. **// //** 2 Use the Periodic Table to predict properties of elements by means of groups and periods. **//


 * //9.1 Periodic trends//**
 * // 1 Describe the change from metallic to non-metallic character across a period. //**
 * // 2 Describe the relationship between Group number, number of outer-shell (valency) electrons and metallic/non-metallic character. //**

__Properties of transition metals__ • high densities • high melting points • forms coloured compounds • can act as catalysts to speed up reactions <span style="background-color: #ffffff; color: #1a1a1a; display: block; font-family: &#39;Open Sans&#39;,sans-serif; font-size: 14px; text-align: justify;">• form coloured compoundsExamples: <span style="background-color: #f5f4f4; color: #6f5e4e; font-family: Arial,Helvetica,sans-serif; font-size: 12.96px;">Iron in the Haber Process and Vanadium Oxide in the Contact Process =<span style="color: var(--ytd-video-primary-info-renderer-title-color,var(--yt-primary-text-color)); font-family: var(--ytd-video-primary-info-renderer-title-font-family,inherit); font-size: var(--ytd-video-primary-info-renderer-title-font-size,1.8rem);">C3: [|The Haber Process](Revision) <span style="color: var(--ytd-video-publish-date-color); font-family: Roboto,Arial,sans-serif; font-size: 1.3rem;">Published on 19 Nov 2015 = || media type="custom" key="29447907" <span style="background-image: url(">[|What is the Haber Process] | The Chemistry Journey | The Fuse School <span class="view-count style-scope yt-view-count-renderer" style="color: var(--yt-metadata-color); font-size: 28.8px;">[|FuseSchool - Global Education] || [|Chemistry experiment 24] Oxidation states of vanadium Published on 10 Aug 2014 ||  ||
 * //9.2 Group properties//**
 * // 1 Describe lithium, sodium and potassium in Group I as a collection of relatively soft metals showing a trend in melting point and reaction with water. //**
 * // 2 Predict the properties of other elements in Group I, given data where appropriate. //**
 * // 3 Describe the trends in properties of chlorine, bromine and iodine in Group VII, including colour, physical state and reactions with other halide ions. //**
 * //4 Predict the properties of other elements in Group VII, given data where appropriate.//**
 * //9.3 Transition elements//**
 * // 1 Describe the transition elements as a collection of metals having high densities, high melting points and forming coloured compounds, and which, as elements and compounds, often act as catalysts. //**
 * media type="youtube" key="0hV3HVT662A" width="560" height="315"
 * media type="youtube" key="ymNLgH0mLQ8" width="560" height="315"


 * //9.4 Noble gases//**
 * // 1 Describe the noble gases as being unreactive. //**
 * // 2 State the uses of the noble gases in providing an inert atmosphere, i.e. argon in lamps, helium for filling balloons. //**

//**C10. Metals**// //** 10.1 Properties of metals **// //** 1 Distinguish between metals and non-metals by their general physical and chemical properties. **// //** 3 Explain why metals are often used in the form of alloys. **// //** 2 Identify and interpret diagrams that represent the structure of an alloy. **//
 * Metals and non-metals ** **from KS3**

//**10.2 Reactivity series**// //** 1 Place in order of reactivity: potassium, sodium, calcium, magnesium, zinc, iron, hydrogen and copper, by reference to the reactions, if any, of the elements with: **// //** • water or steam **// //** • dilute hydrochloric acid (except for alkali metals). **// //** 2 Describe the reactivity series to the tendency of a metal to form its positive ion, illustrated by its reaction, if any, with: • the aqueous ions of other listed metals • the oxides of the other listed metals. **// //** 3 Deduce an order of reactivity from a given set of experimental results. **//

Patterns of reactivity from KS3
//**10.3 Extraction of metals**// //** 1 Describe the use of carbon in the extraction of copper from copper oxide. **// //** 2 Describe the essential reactions in the extraction of iron in the blast furnace. **// //** 3 Relate the method of extraction of a metal from its ore to its position in the reactivity series, limited to Group I and II metals, aluminium, iron and copper. **//


 * //C11. air and water//**
 * // 1 State a chemical test for water. //**
 * // 2 Describe and explain, in outline, the purification of the water supply by filtration and chlorination. //**
 * // 3 Describe the composition of clean air as being a mixture of 78% nitrogen, 21% oxygen and small quantities of noble gases, water vapour and carbon dioxide. //**
 * // 4 Explain why the proportion of carbon dioxide in air is increasing, and why this is important. //**
 * // 5 State the formation of carbon dioxide: //**
 * // • as a product of complete combustion of carbon-containing substances //**
 * // • as a product of respiration //**
 * // • as a product of the reaction between an acid and a carbonate //**
 * // • as a product of thermal decomposition. //**
 * // 6 Describe the rusting of iron in terms of a reaction involving oxygen and water, and simple methods of rust prevention, including paint and other coatings to exclude oxygen. //**

//**C12. Organic chemistry**// //** 12.1 Fuels **// //** 1 Recall coal, natural gas and petroleum as fossil fuels that produce carbon dioxide on combustion. **// //** 2 Name methane as the main constituent of natural gas. **// //** 3 Describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation. **// //** 4 Understand the essential principle of fractional distillation in terms of differing boiling points (ranges) of fractions related to molecular size and intermolecular attractive forces. **// //** 5 State the use of: **// //** • refinery gas for bottled gas for heating and cooking **// //** • gasoline fraction for fuel (petrol) in cars **// //** • diesel oil/gas oil for fuel in diesel engines. **//

//**12.2 Hydrocarbons**// //** 1 Describe the properties of alkanes (exemplified by methane) as being generally unreactive, except in terms of burning. **// //** 2 State that the products of complete combustion of hydrocarbons, exemplified by methane, are carbon dioxide and water. **// //** 3 Name, identify and draw the structures of methane, ethane, ethene and ethanol. **// //** 4 Recognise alkanes and alkenes from their chemical names or from molecular structures. **// //** 5 Describe the manufacture of alkenes by cracking. **// //** 6 Distinguish between alkanes and alkenes by the addition reaction of alkenes with bromine. **//