C1 Smart Teach 5: Fuels

Fractional Distillation By what process is crude oil separated into its fractions Fractional distillation that takes place at a refinary FractionLength of molecules Ease of ignition ViscosityUSE GasesShort carbon chains Long Carbon Chains Easy Difficult Runny Thick and Sticky Cooking Fuel for cars Road surfaces Petrol Kerosene Diesel oil Fuel Oil Bitumen Exam HINT It is quite common to be asked to compare the properties and uses of different fractions. Remembering this table can help you to do so

Cracking Breaking down long alkanes into smaller alkanes and alkenes Long alkenes are in lower demand. Shorter alkanes are in high demand and alkenes are used to make plastics. What is cracking? Why do we crack hydrocarbons?

Burning Fuels In a combustion reaction an fuel is burnt in oxygen to give carbon dioxide and water Fuel + Oxygen  Carbon dioxide + Water ____ + O 2  CO 2 + H 2 O The rest of the equation stays the same, only the fuel changes and this is usually given in the equation. E.g. Methane + Oxygen  Carbon dioxide + Water The rest of the equation stays the same, just writing this would get you one mark, the formula for the fuel is usually in the question, for the final third mark then you balance.

Burning Fuels What is incomplete combustion? When there is insufficient oxygen in a combustion reaction What are the products of incomplete combustion? Soot (carbon) and or carbon monoxide What negative effects can the products of in complete combustion have? Soot: stains surroundings, blocks appliances, causes health problems: makes asthma worse Carbon monoxide: toxic, combines with haemoglobin in the blood, therefore red blood cells can no longer carry oxygen, as a result respiration can not take place.

a. Write down the word equation for the complete combustion of a hydrocarbon. You need to state the reactants and the products. (2 marks) Question a – Burning Fuels Some bus companies are converting their buses to run on bio-methane produced from food waste. Bio-methane is a hydrocarbon. northseabioenergy.org/wp-content/uploads/2014/07/bio-bus-in-Europe.png

a. Write down the word equation for the complete combustion of a hydrocarbon. You need to state the reactants and the products. (2 marks) Answer a – Burning Fuels Some bus companies are converting their buses to run on bio-methane produced from food waste. Bio-methane is a hydrocarbon. northseabioenergy.org/wp- content/uploads/2014/07/bio-bus-in-Europe.png Hydrocarbon + Oxygen Carbon dioxide + Water

Different Fuels What makes a good fuel? Type of fuel Petrol (fossil fuels) HydrogenBiofuel Advantages Gives off a lot of energy Most cars are compatible with the fuel The hydrogen comes from the electrolysis of water. Water is readily available. The only product is water Renewable Crops can be grown quickly Reduces demand on fossil fuels. When plants are growing carbon dioxide is removed from the atmosphere. Disadvantages Non renewable Contains sulphur Produces carbon dioxide that can cause global warming Electrolysis requires a lot of energy, this uses fossil fuels and adds carbon dioxide to the atmosphere. Expensive to produce Dangerous to store Less readily available than fossil fuels. A large amount of crops would need to be grown to replace fossil fuels. Farmland used to grow the crops can no longer be used for food. Few cars are compatible with the fuel. Contains no sulphur, gives off a lot of heat energy, safe to store, safe to transport, safe to use. Easy to ignite, carbon neutral. Produces little or no carbon dioxide.

Acid Rain and Global Warming How does burning fossil fuels cause global warming? Carbon dioxide and water produced from burning fossil fuels are green house gases that trap heat Explain how sulphur in fuel causes acid rain and the effects it has Sulfur impurities in the fuel react with oxygen to form sulphur dioxide. Sulfur dioxide dissolves in rain to form acid rain. Acid rain harms plants and can damage buildings

b. QWC: Coal used in power stations to generate electricity can contain high levels of sulfur. This can have a huge impact on the environment. Explain how burning coal that has a high sulfur content causes pollution and the impact it has on the environment. (7 marks) Question b – Burning Fuels

b. QWC: Coal used in power stations to generate electricity can contain high levels of sulfur. This can have a huge impact on the environment. Explain how burning coal that has a high sulfur content causes pollution and the impact it has on the environment. (7 marks) Answer b – Burning Fuels When coal containing sulfur burns the sulfur reacts with oxygen to produce sulfur dioxide gas. The sulfur dioxide gas then mixes with the water vapour in the atmosphere (clouds) and reacts to form sulfuric acid. This then falls as acid rain. The impact of acid rain on the environment is that it can acidify lakes and other water sources to kill plants and animals. It can also kill other plants and trees.

Alkanes and Alkenes Define these terms: A molecule containing carbon and hydrogen atoms ONLY A hydrocarbon with single bonds between each carbon atom A hydrocarbon with a double bond between two carbon atoms A hydrocarbon with single bonds between each carbon atom A hydrocarbon with a double bond between two carbon atoms Hydrocarbon Alkane Alkene Saturated Unsatuated Describe a test for unsaturation. Add bromine water to your unknown solution. If the bromine water stays orange then the substance is saturated (an alkane) if bromine goes from orange to colourless then the substance is unsaturated (alkene)

Polymerisation Monomer NamePolymer Name EthenePoly(ethene) PropenePoly(propene)

a. The structure of this monomer forms a polymer. Draw the polymer that it forms. (2 marks) Question a – Polymerisation

a. The structure of this monomer forms a polymer. Draw the polymer that it forms. (2 marks) Answer a – Polymerisation

b. Explain how a polymer forms from its monomers. (4 marks) Question b – Polymerisation

b. Explain how a polymer forms from its monomers. (4 marks) Question b – Polymerisation In polymerisation many monomers join (bond, link, combine) to form a long-chain molecule. For this to happen the double must open up (break) and then each monomer bonds to the next monomer.