Starter Which of the following statements are true or false? Write the statement number and T/F for each one in your books. 1.An element is made up of only one type of atom 2.A compound can be easily separated 3.A mixture is made up of two or more elements or compounds 4.In a compound, the elements are chemically bonded 5.In a mixture, the elements or compounds are chemically changed 6.A mixture can be separated easily

Module C1.4 Crude oil and fractional distillation

Video about crude oil ( Watch the video about crude oil and jot down answers to the following: What is crude oil made of? How did it form?

Crude oil Crude oil is a mixture of a very large number of compounds and is made from the bodies of plants and animals that have decayed many millions of years ago. A mixture is two or more substances NOT chemically combined together (such as a mixture of sand and water that can be separated by filtration).

Crude Oil Formation

Hydrocarbons Most of the compounds in crude oil consist of molecules made up of hydrogen and carbon atoms only. We call these HYDROCARBONS We can separate the different unchanged hydrocarbons from crude oil by FRACTIONAL DISTILLATION. Watch the video about oil refining and complete the worksheet Watch the video about oil refining and complete the worksheet

Uses of crude oil Crude oil can be separated using a technique called FRACTIONAL DISTILLATION Fractional distillation produces products we can use for lots of different applications. What applications did you come up with?

Jet fuel

Petrol and diesel

Plastics and polymers

Fractional distillation Fractional distillation separates a mixture into a number of different parts, called fractions. A tall column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with low boiling points condense at the top. Fractional distillation works because the different substances in the mixture have different boiling points. Fractional distillation Watch video on fractional distillation.

What is distillation? Distillation is used to separate mixtures using their boiling points When we heat up a mixture past its boiling point, it evaporates, turning from a liquid into a gas. Because different compounds have different boiling points, they will evaporate at different temperatures. Could we use distillation to separate ink and water?

Fractional distillation

Key points for exam questions To explain fractional distillation [3 marks] 1.Heat crude oil to make it a gas/vapour 2.Cool to condense 3.Hydrocarbons condense at different temperatures (boiling points).

Different hydrocarbon – different BP Different hydrocarbons have different numbers of carbon atoms. The higher the number of carbon atoms the higher its boiling point.

Key points for exam questions A fraction is a set of hydrocarbon molecules of similar size and similar boiling points

C1.4 Crude oil Lesson 3 - alkanes

Using your knowledge from last lesson complete these questions (You have 5 minutes!) Name three fossil fuels (E grade) What is a crude oil fraction? Name 3 fractions and give their uses. (C grade) Describe how crude oil is separated into fractions by fractional distillation. Use the words boil, evaporate and condense in your answer. (A* grade)

The answers (Swap your answers with your neighbour, mark the work, give a grade and comment on how they could improve their grade) Coal, oil, gas (3 marks) A proportion of crude oil that has been separated according to its boiling point. E.g. kerosene – aeroplane fuel, fuel oil – ship fuel, refinery gas – stove fuel, bitumen – road surfacing (4 marks) Crude oil is heated until it boils and becomes a gas, the gas rises up the fractionating column and starts to cool. Fractions condense based on their boiling point – shorter chains boil at lower temperatures and therefore condense higher up the fractionating column. (4 marks)

Hydrocarbons CRUDE OIL Fractional distillationALKANES Crude oil is a mixture of hydrocarbons of different chain lengths. They are separated in fractional distillation by boiling point. The chemical name for the group of hydrocarbons produced from fractional distillation is alkane. Alkanes only contain carbon and hydrogen bonded together by single bonds

Alkanes Alkanes are the name of a type of chemical that makes up the compounds in crude oil. They are hydrocarbons (contain only hydrogen and carbon) and form a series of increasing molecular weight.

Carbon chains Alkanes are chains of carbon atoms with hydrogen atoms attached to them. There is an alkane with one carbon atom, two carbon atoms, three, four, five and so on. The chains can be massive with hundreds of carbon atoms. You need be able to name and draw the first four and recognise some larger ones.

Alkanes Alkanes are saturated Saturated means that all of the atoms are held together by single covalent bonds, for example CH 4 Methane (the simplest alkane) Displayed formula Molecular formula Single bonds

Methane One carbon atom bonded to four hydrogen atoms. Each line represents a single covalent bond.

Ethane Two carbon atoms six hydrogen atoms

Propane Three carbon atoms eight hydrogen atoms

Butane Four carbon atoms ten hydrogen atoms

Can you spot a pattern? Every time we increase the number of carbons what happens to the number of hydrogens? We can work out a general formula for any alkane it is: C n H 2n+2 where n is the number of carbon atoms and 2n+2 is the number of hydrogen atoms

Counting in chemistry Rather than the numbers 1,2,3 and 4 when we are counting in chemistry we use the terms: meth_ = 1 eth_ = 2 prop_ = 3 but_ = 4 The first four alkanes are therefore called methane, ethane, propane and butane.

Naming alkanes Ethane, C 2 H 6 Propane, C 3 H 8 Butane, C 4 H 10 H H H H H H—C—C—C—C—C—H H H H H H Methane, CH 4 Pentane, C 5 H 12 Name all longer chains using shape names

Task 1.Draw the structures of the five alkanes up to Pentane 2.Write their molecular formula in the box 3.Try to work out the value of ‘n’ in the following examples of alkanes; 1.C 10 H n 2.C 8 H n 3.C 15 H n 4.C n H 10 5.C n H 22 6.C n H 30

C1.4 Crude Oil Lesson 3 – properties of hydrocarbons

Starter - Quiz 1.What is the name of the alkane with the formula CH 4 2.What is the name of this alkane? 3.Draw a molecule of propane showing all the bonds.

Starter - Quiz 1.What is the name of the alkane with the formula CH 4 - methane 2.What is the name of this alkane? ethane 3.Draw a molecule of propane showing all the bonds.

Spot the difference

Ethane All single bonds Full of hydrogen Saturated Ethene Has double bond Fewer hydrogens Unsaturated

Properties Some properties of hydrocarbons depend on the size of their molecules. These properties influence how hydrocarbons are used as fuels. Identify solids, liquids and gases in the following images…

Liquid or gaseous fuels

Liquid/Gas For this list of substance state whether liquid or gas at room temperature? HydrocarbonBoiling point in °CSolid/Liquid/Gas methane, CH butane, C 4 H 10 0 pentane, C 5 H decane, C 10 H

Boiling Point Boiling point increases with chain length. This is due to the increased number of intermolecular forces between molecules as the chain gets longer

Viscosity – new keyword This simply means thickness of solution. For example water has a lower viscosity than treacle Generally the higher the molecular weight (longer carbon chain) the more viscous the substance is. Bitumen has very long chain molecules and is very viscous and stick (tar).

Viscosity Viscosity increases as you increase the number of carbons Long chain alkanes are very thick and gloopy Short chain alkanes are runny (or gases!) Again this is mainly due to intermolecular bonding.

Flammability & Volatility The alkanes get less flammable as you increase the number of carbons This is related to how volatile they are, which also decreases as you increase the chain length. The simplest alkanes turn into a gas readily

Starter List as many hydrocarbon fuels as you can. Think back to the diagram of fractional distillation of crude oil. What examples can you remember?

Did you get? Methane Propane Butane Petrol Diesel Kerosene Fuel oil + many more

Burning fuels releases energy! bustion-of-natural-gas/1854.html bustion-of-natural-gas/1854.html Demo Combustion apparatus using candle

Combustion Complete combustion occurs when there is enough oxygen – for example when the hole is open on a Bunsen burner. The products of complete combustion are carbon dioxide and water. CH 4 + 2O 2  CO 2 + 2H 2 O Combustion Demo

Combustion Combustion is……. Combustion is the scientific word for burning.

Combustion Colour at the startColour at the end Cobalt Chloride paper Limewater Cobalt Chloride paper can be used to test for ____________ Limewater can be used to test for ________________

The Science behind combustion Fuels are Hydrocarbons During combustion the carbon and hydrogen atoms in the fuel are oxidised Methane + OxygenCarbon dioxide + Water + Energy CH 4 + 2O 2 CO 2 + H 2 O + Energy

Combustion Complete combustion Carbon dioxide Water Energy Partial combustion Carbon monoxide Carbon Water AB Q1. which flame is showing complete and Partial combustion? Q2. How would you set up a Bunsen burner to achieve flame B? Q3. A gas fire with a yellow coloured flame is dangerous because......

AfL - Complete combustion

Incomplete combustion Incomplete combustion occurs when there is not enough oxygen – for example when the hole is closed on a Bunsen burner. The products of incomplete combustion include carbon monoxide and carbon (soot). It is often called a sooty flame.

AfL – incomplete combustion

Carbon dioxide

Carbon monoxide

Soot/smoke particles

Other pollutants

Environmental problems Sulfur Dioxide and Oxides of Nitrogen Carbon Dioxide Carbon particles ________is linked to acid rain. Increased levels of these chemicals are turning rain water acidic, causing fish and trees to die. _______is linked to the greenhouse effect. Increased levels of this chemical are trapping the Sun’s energy, causing the climate to warm up. ___________are linked to global dimming. This results in more sunlight being reflected, which reduces the total sunlight reaching the Earth.

Acid rain

Cleaning up Undesirable combustion products can be cleaned from emissions before they leave the chimney by using a filter or catalytic converter (cars).

Cleaning up 2 Give out pollution/equations sheet Give out pollution/equations sheet Chemical scrubbersLow Sulfur fuels Remove Sulfur from fuels before they burn Remove Sulfur dioxide from the waste gases after combustion

Exam question 1d

Exam question 7c

Exam question 10

C1.4 Crude Oil Lesson 5 - Biofuels

Objectives Recall that biofuels are produced from plant material Describe the fuels that can be produced from plant material Evaluate the advantages and disadvantages of making fuel from renewable sources.

Starter Can you recall some of the uses of crude oil?

The problem with crude Crude oil is a limited resource that will eventually run out. Alternatives are needed and some are already under development.

Biofuels A biofuel is any fuel that is made from plant or animal material. For example, biodiesel is made from oils extracted from plants. You can use old cooking oil as a biofuel – this is becoming more and more common Biogas is generated from animal waste Biofuels in general will become more important as our supplies of crude oil run out.

Alternative fuels uels/476.html uels/476.html eZps eZps

What are the advantages? Breaks down quicker – less harmful to plants and animals Burns cleaner – less particulates and sulfur dioxide Cheaper to use as crude oil prices go up Biofuels in theory are ‘carbon neutral’ – carbon released is equal to carbon taken in when photosynthesising Making biodiesel produces other useful products such as a solid waste material we can use as cattle feed. Diesel engines do not need adapting to run off biodiesel Is not 100% carbon neutral

Disadvantages? Would require large areas of farmland which may take the place of crops that would be used for food – famine in poorer countries, clearing of forests etc Destruction of habitats of endangered species – this is already happening where tropical forest is being cut down for palm oil At low temperatures, biodiesel will freeze before traditional diesel would – ‘gums up engines’ Is not 100% carbon neutral

Carbon neutral Plants photosynthesise using carbon (dioxide) from the air Biodiesel/biothanol releases carbon (dioxide) from plants Plants are replanted and photosynthesise, removing the carbon (dioxide) again. (fossil) diesel from crude oil releases ‘locked up’ carbon (dioxide) and doesn’t absorb any CO 2

Different types of biofuels Ethanol – produced by fermentation of sugars in sugarcane Biodiesel – produced from hydrolysis of vegetable oils

Ethanol & Hydrogen Ethanol Made by fermenting sugar Added to petrol Gives off CO 2 but sugar cane absorbs this when growing Hydrogen Burns well and cleanly – no carbon! Water is only product Made from water through hydrolysis – this requires energy. Very explosive Is a gas - storage

Examination question Q14 (b)

Mark scheme

Past paper question.

Mark scheme