06/03/2016 C1 – Carbon Chemistry Revision Lesson part one

06/03/2016 Revision Lessons Does not contain all of the content for C1 – use checklists..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Foundation.doc..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Higher.doc..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Foundation.doc..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Higher.doc..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Foundation.doc..\C1 Carbon Chemistry\C1 Summary & Checklists\C1 Checklist Higher.doc

06/03/2016 The Chemistry of Cooking The process of cooking food causes some chemicals to turn into others (i.e. a chemical change) and these are irreversible. For example, consider a protein molecule: “Denatured”

06/03/2016 Exam Questions Standard Demand 1.) Some foods need to be cooked. Explain why? (2 marks) 2.) Cooking food is an example of a chemical change. Finish the sentences to explain why. Choose the best words from the list. Energy irreversible reactant reversible substance The change is___________. An ___________ change takes place in the food. A new ________ is made. (3 marks) 3.) What happens to protein molecules when they are cooked? (1 mark)

06/03/2016 The Chemistry of Cooking Now consider a potato cell: Cooking a potato causes the cell wall to break and release starch grains – making it softer/easier to digest

06/03/2016 Baking Powder Baking powder is used to make bread rise: This is a thermal decomposition reaction Sodium hydrogen carbonate sodium carbonate + water + carbon dioxide NaHCO 3(s) Na 2 CO 3(s) + H 2 0 (g) + CO 2(g) 2 Gas Limewater turns milky/cloudy Limewater Testing for carbon dioxide - makes cakes/bread rise:

06/03/2016 Exam Questions Standard Demand 1.) Baking powder is a chemical called sodium hydrogencarbonate. When it is heated it decomposes to give sodium carbonate, carbon dioxide and water. a.) Write down the word equation for this reaction. (2 marks) b.) Write down the reactants of the reaction. (1 mark) c.) Write down the products of the reaction. (1 mark) 2.) The chemical test for carbon dioxide is to pass it through limewater. It will turn the limewater from _______ to _______.(2 marks)

06/03/2016 Exam Questions High Demand 1.) The formula for sodium hydrogencarbonate is NaHCO 3. Write down the balanced symbol equation for this reaction.(3 marks)

06/03/2016 Food Additives

06/03/2016 Artificial Additives Why do we use additives? Some examples: AdditiveWhy Flavour enhancers Bring out taste and smell of food Food colouringmakes food look more appetising AntioxidantsStops reaction with oxygen, preserves food EmulsifiersHelp oil and water mix in foods like salad cream and ice cream

06/03/2016Emulsions What’s an emulsion? It’s a mixture of oil and water, like in salad dressing… Paint is an emulsion. Other examples: MilkCreamButter Butterfat Watery liquid

06/03/2016 Emulsifiers - the details Emulsifier Water Oil

Foundation – 6 mark question The quality of written communication will be assessed in your answer to this question. Explain why cooking a meat is described as a chemical change. 06/03/2016

Level 3 Answer correctly applies knowledge of how meat is a protein, description of how cooking is a chemical change because it involves an energy change that is irreversible. Understanding of how proteins change shape-denatures. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how cooking meat is a chemical change due to heating the food, causing an energy change and irreversible reaction. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states cooking is a chemical change because the reaction is irreversible. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

Higher - 6 mark question The quality of written communication will be assessed in your answer to this question. Explain how even though mayonnaise is made of oil, vinegar and egg yolk, it still makes a smooth substance. 06/03/2016

Level 3 Answer correctly applies knowledge of how egg yolk has two part, one part is hydrophobic and the other part is hydrophilic, description of how these two parts allow the oil and water in mayonnaise to stay together.All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how emulsifiers work. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states an emulsifier description. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

06/03/2016Smells

Perfumes Here are some facts about perfumes. Why are these things important? 1)Perfumes are non-toxic 2)They are non-irritants 3)They evaporate easily 4)They do not dissolve in water 5)They don’t react with water A typical perfume reaction: Ethanol + ethanoic acid ethyl ethanoate + water C 2 H 5 OH + CH 3 COOH C 2 H 5 OOCCH 3 + H 2 O

06/03/2016 Solutions revision If a substance CAN be dissolved it is called __________ If a substance CANNOT be dissolved it is called _________ Words – soluble, solute, solvent, solution, insoluble

06/03/2016 Higher - Making a solution A solution forms because there are: 1)Weak forces of attraction between solute molecules 2)Strong forces of attraction between solute and solvent molecule For example, nail varnish remover works because the nail varnish remover molecules are attracted to the nail varnish molecules with a stronger attraction than water molecules are.

06/03/2016 Exam Questions Standard Demand 1.) To make a perfume alcohol is mixed with an acid to make an ester. a.) Write down a word equation for this reaction. b.) Write down the name of the ester that is made from ethanoic acid and butanol. 2.) Some people object to cosmetics being tested on animals. Explain why 3.) Some people say that cosmetics should be tested on animals. Explain why. 1. alcohol + acid ester + water 2. Butyl ethanoate 3. Animals may be harmed, they have no control of what happens to them 4. Feel safer if cosmetics have been tested on animals, animals reaction would closely mimic ours

06/03/2016 Exam Questions High Demand 1.) If a liquid evaporates easily then the substance is volatile. Explain how this happens. Use ideas about forces between particles in your answer.(4 marks) 2.) Water does not dissolve nail varnish. Use ideas about the forces of attraction between molecules in your answer.(2 marks) 1. When a liquid is heated, particles will move faster, these will overcome the forces of attraction of other particles and escape, meaning the substance evaporates easily, it s volatile. 2. Molecules of nail varnish are strongly attracted to each other, and this attraction is stronger than the one between the water molecules and nail varnish

06/03/2016 Making crude oil useful

06/03/2016Alkanes Alkanes are SATURATED HYDROCARBONS. What does this mean? HYDROCARBONS are molecules that are made up of hydrogen and carbon atoms SATURATED means that all of these atoms are held together by single bonds, for example: Ethane Alkanes are fairly unreactive (but they do burn well). C C H H H HH H Butane CC H H H HH H C C H H H H

06/03/2016Fuels Fuels are substances that can be used to release useful amounts of energy when they burn, e.g. Oil Gas Wood Coal These fuels are called “fossil fuels” and are described as being “non-renewable”.

06/03/2016 Crude Oil

06/03/2016 Hydrocarbons and crude oil Longer chains mean… 1.Less ability to flow 2.Less flammable 3.Less volatile 4.Higher boiling point Increasing length Crude oil is a mixture of HYDROCARBONS (compounds made up of carbon and hydrogen). Some examples: Ethane C C H H H HH H Butane CC H H H HH H C C H H H H

06/03/2016 General Formulae for Alkanes Instead of circles, let’s use letters… General formula for alkanes = C n H 2n+2 Butane (n=4) H C C H H H H C C H H H HH Methane (n=1) H C H H H Ethane (n=2) H H C C H H H H Propane (n=3) H C H H H C C H H H H

06/03/2016Alkenes Alkenes are different to alkanes; they contain DOUBLE COVALENT bonds. For example: Ethane Ethene Butane Butene This double bond means that alkenes have the potential to join with other molecules – this make them REACTIVE. ALKANES ALKENES

06/03/2016 General Formulae for Alkenes General formula for alkenes = C n H 2n Propene (n=3) H C H H H C C H H Ethene (n=2) H H C C H H Butene (n=4) H C C H H H H C C H HH Higher Alkenes react with Bromine water Alkene + Bromine Water = Colourless Solution + Br 2 = H H C C H H Br H C C H H H

06/03/2016 Fractional distillation Crude oil can be separated by fractional distillation. The oil is evaporated and the hydrocarbon chains of different lengths condense at different temperatures: Fractions with low boiling points condense at the top Fractions with high boiling points condense at the bottom

Remember! – It’s the forces between the molecules that are broken. The forces within the molecules (covalent bonds) are not affected by heating. covalent bond – can’t break these!

06/03/2016 Forces between molecules Weak intermolecular force of interaction here Longer molecules = stronger intermolecular force of attraction

06/03/2016Cracking Shorter chain hydrocarbons are in greater demand because they burn easier. They can be made from long chain hydrocarbons by “cracking”: Butane Ethane For example, this bond can be “cracked” to give these: Ethene

06/03/2016Cracking This is a THERMAL DECOMPOSITION reaction, with clay used as a catalyst INVOLVES HEAT AND A CATALYST Cracking can be used (as well as fractional distillation) to extract petrol from crude oil. Helps supply and demand!!!!!! Long chain hydrocarbon - paraffin Heated catalyst Shorter alkane - octane Alkene - ethene

06/03/2016 Exam Questions Standard Demand 1.) All the oils of crude oil are hydrocarbons. What is a hydrocarbon?(2 mark) 2.) Explain how damage is done to the environment if oil tankers are damaged.(2 marks) 3.) When a large alkane is cracked it becomes a smaller alkane and an alkene. Explain why an alkene is a different type of hydrocarbon to an alkane.(1 mark) 4.) What are alkenes useful for making?(1 mark) 1. Contains hydrogen and carbon only 2. harm animals, pollutes beaches and destroys unique habitats 3. Alkenes are unsaturated (double bond) therefore more reactive 4. Polymers (plastics)

06/03/2016 Foundation - 6 marker question The quality of written communication will be assessed in your answer to this question. 1.) A country produces 25% more than its demand of heavy oil from crude oil distillation. However, its supply of petrol from the distillation is only 68% of its need. Explain how they could solve this problem.

06/03/2016 L evel 3 Answer correctly applies knowledge of how alkanes like paraffin can be broken down into more useful products such as petrol, by the process of cracking. Detailed description of cracking, including thermal decomposition reaction, high temperature and use of a catalyst. All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how cracking can be used to deal with supply and demand. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states that cracking can be used to supply petrol. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)

06/03/2016 Higher - 6 marker question The quality of written communication will be assessed in your answer to this question. 1.) Explain why crude oil can be separated by fractional distillation. Use ideas about chain length, forces of attraction and boiling points in your answer. (6 marks)

06/03/2016 L evel 3 Answer correctly applies knowledge of how crude oil can be separated by fractional distillation because molecules in different fractions have different length chains. Long chain molecules, such as bitumen have strong forces of attraction between molecules, meaning alot of energy is needed to break each molecule away from another, so they have high boiling points..All information in answer is relevant, clear, organised and presented in a structured and coherent format. Specialist terms are used appropriately. Few, if any, errors in grammar, punctuation and spelling. (5–6 marks) Level 2 Answer applies knowledge of how crude oil is separated by fractional distillation, including part of points but not all. For the most part the information is relevant and presented in a structured and coherent format. Specialist terms are used for the most part appropriately. There are occasional errors in grammar, punctuation and spelling. (3–4 marks) Level 1 An incomplete answer, states how fractional distillation works. Answer may be simplistic. There may be limited use of specialist terms. Errors of grammar, punctuation and spelling prevent communication of the science. (1–2 marks) Level 0 Insufficient or irrelevant science. Answer not worthy of credit. (0 marks)