The straight chain alkanes share the same general formula. The fractional distillation of crude oil produces alkanes. Combustion substitution with halogens catalytic cracking. Model the industrial process of cracking larger hydrocarbons to produce smaller alkanes that can be converted into petrol.
Vapours will then pass over a hot catalyst of silica. Alkanes consist of strong covalent bonds therefore they are, on the whole, quite unreactive. At fuse school, teachers and animators come together to make fun. As bond breaking is a random process, a variety of products can be formed. Crude oil hydrocarbons and alkanes aqa test questions. Give an example of a method by which cracking can be carried out. Learn gcse chemistry alkanes with free interactive flashcards. Pupils can share their ideas in pairs, then as a class, before being introduced to the process of cracking.
This is called catalytic cracking and is an example of a thermal decomposition reaction. The best way to remember the information in this chapter is to get a pen and paper and write down your answers. Gcse chemistry revision questions fossil fuels crude. See all chemistry resources see all crude oil, cracking and hydrocarbons. These resources are specifically designed for senfoundation students studying gcse chemistry ocraqa. Crude oil hydrocarbon alkane cracking alkene polymer objectives. Alkenes along with alkanes can be produced from cracking. Choose from 500 different sets of gcse chemistry alkanes flashcards on quizlet.
High octane starter to inject pace which is easily adapted for other lessons. Their most important reaction is that of combustion. Cracking of alkanes craking refers to the process where cc bonds in long chain alkanes molecules are broken, producing smaller molecules of alkanes and alkenes. Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa. Learn about and revise fuels with this bbc bitesize gcse chemistry edexcel study guide. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits.
Two methods of cracking how to write a balanced equation for cracking what an alkene is, and how they differ from an alkane. Gcse chemistry what is the chemistry of the cracking of. And be careful with your phrasing cracking produces alkenes and shorter chain alkanes. Hydrocarbons from oil a2levellevelrevision, chemistry. You need to know about alkanes, alkenes, crude oil and the process of cracking. C 16 h 34 is an alkane which can be used as the starting chemical in cracking. Cracking helps match supply of fractions with demand. The main chemical reactions that alkanes undergo are. Because i have written this blog post specifically for igcse chemistry students. Gcse chemistry what is the cracking of hydrocarbons. Learn the basics about the cracking of hydrocarbons and why it is done. Best igcse organic chemistry notes complete breakdown. I print the starter as as handout sheet so they only have to complete the cloze exercise without writing everything.
Stick with shorter as opposed to short because if you crack a larger alkane you could end up with an alkane as a product that you wouldnt normally describe as short. Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules. There is a greater demand for smaller hydrocarbons than larger ones. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too. The general formula means that the number of hydrogen atoms in an alkane is double the number of carbon atoms, plus two. Gcse chemistry revision organic chemistry crude oil. A level chemistry aqa specification alkanes modification of alkanes by cracking quick jump menu unit 1 notes unit 2 notes unit 3 experimental unit 4 notes unit 5 notes unit 6 experimental home. Nov 14, 2017 in this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. The best way to remember the information in this chapter is to get a pen and paper and write down your answers before clicking on the answer link which will take you to the correct page you may have to read through some of the page before you find the answer. Cracking an alkane produces a smaller alkane plus an alkene. Cracking oil fractions reaction conditions products equations. Organic chemistry now forms a substantial part of the gcse specifications. Before joining or doing any activity please read the guidelines of the. Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a process known as cracking.
Cracking oil and cracking gcse chemistry single science. This means that their carbon atoms are joined to each other by single bonds. Outline of practical work is included but follow centre basedcleaps safety guidelines. Aqa chapter 7 hydrocarbons in this lesson students will learn. The covalent bond is broken so each carbon has this mechanism. New91 aqa gcse chemistry c9 crude oil and fules kerboodle. This is achieved by using high pressures and temperatures without a catalyst, or lower temperatures and pressures in the presence of a catalyst. Year 12 lesson graded outstanding to teach cracking.
A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. Graded with a video link and mark schemes for everything. From the physical properties of the alkanes, it can be established that. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. Designed by expert teachers for the edexcel gcse 91 chemistry syllabus. As well as using a normal type of molecular formula to describe an organic molecule, they can be represented by drawing out their structure i. By the end of this lesson ks5 students should be able to. This makes them relatively unreactive, apart from their reaction with oxygen in the. Dec 31, 2015 summary video on cracking for gcse chemistry. Vapours will then pass over a hot catalyst of silica or alumina. After the fractional distillation of crude oil there are too many large hydrocarbons and not enough small hydrocarbons to meet the publics demand. The larger alkanes are heated to around 650c and their vapours are passed over a hot catalyst. The breaking of longer chain alkanes in order to produce a smaller alkane and an alkene. The american chemist, william burton, is usually credited with being the inventor of the thermal cracking process.
Nov 04, 2009 how many grams of liquid can be produced from decomposition of 758. If you are an igcse chemistry student desperately looking for the perfect organic chemistry notes, then this is the one. Gcse chemistry senfoundation crude oil, alkanes, frac. During cracking, the long molecules break apart, forming smaller alkanes and alkenes. Cracking is a thermal decomposition process by which large alkane hydrocarbon. Gcse chemistry unit 1 cracking alkanes to make alkenes cracking alkanes to make alkenes. Cracking is the name given to breaking up large hydrocarbon molecules into. Please comment if you have any questions, and subscribe if you. Chemistry revision notes on the topic cracking hydrocarbons. We also look at alkenes and how we test for alkenes using bromine water. Cracking fuels edexcel gcse chemistry single science.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. All liquid alkanes are less dense than water and therefore float on it. Cracking edexcel igcse chemistry notes save my exams. A structured lesson including starter activity, afl work tasks on cracking of alkanes. In this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. One of these is thermal cracking which is used on crude oil. Cracking and alkenes crude oil, hydrocarbons and alkanes. Alkenes are reactive molecules that are used to make plastics and other chemicals.
Written by teachers for the edexcel igcse chemistry course. Organic chemistry introduction 1 structural formulae. First, crack the vapour of liquid paraffin by passing it over a heated catalyst to produce and collect a mixture of gaseous shortchain hydrocarbons. The alkanes from pentane through to c 16 are liquids with the remainder larger molecules being solids. Crude oil hydrocarbons and alkanes aqa test questions aqa. Aqa gcse 91 chemistry 8462 past exam papers and marking schemes, the past papers are free to download for you to use as practice for your exams. They do not react with acids, alkalis, and oxidising agents. To describe what cracking is and its economic benefits. C1 alkanes and alkenes, cracking and polymers flashcards. Cracking cracking is the breaking down of an unsaturated hydrocarbon into smaller hydrocarbons. Fractions containing large hydrocarbon molecules are heated at 600 700c to vaporise them. For example, as the chain length increases, their boiling point increases.
They cover formation of crude oil, hydrocarbons, alkanes, fractional distillation, alkenes and polymerisation. Oct 25, 2017 lesson planpowerpoint to teach cracking of alkanes. If you add up the number of hydrogen atoms in the above reaction, you will see that there are 22 on each side. Covalent bonds are formed when atoms share pair of electrons. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking paraffin. Gcse chemistry revision science section covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single and double covalent bonds, and cracking paraffin. Alkanes alkanes are saturated hydrocarbons contain single. Heat longchain hydrocarbon to vaporise it, pass the vapour over a hot catalyst. This blog only covers the organic chemistry topics which are included on the igcse chemistry syllabus. A brief description of the difference between thermal and catalytic cracking of alkanes. Covers thermal and catalytic cracking, ppt file, application questions, answers and an assessed homework activity with mark scheme. Gcse chemistry unit 1 cracking alkanes to make alkenes. Most of the hydrocarbons in crude oil are hydrocarbons called alkanes. In addition to this you will need to know about functional groups such as alcohols, carboxylic acids and esters and how to draw their structures.
Cracking is a very important process used in the petrochemical industry to break down the large hydrocarbons intro smaller hydrocarbons, which burns more easily as fuel. Cracking hydrocarbons in liquid paraffin with a catalyst. As chemistry aqa cracking alkanes teaching resources. This makes them relatively unreactive, apart from their reaction with oxygen in the air, which is called combustion, or burning.
You need to understand certain chemical reactions used in a variety of industrial processes for gcse chemistry. Cracking hydrocarbon chains will be expected for all three exam boards which are. Written by teachers for the cie igcse chemistry 91 course. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking. Apparatus delivery tube and bung bunsen burner boiling tube containing mineral wool porous pot liquid paraffin clamp and stand. Aqa chapter 7 hydrocarbons lesson 3 cracking alkanes. Hydrocarbons are chain molecules of varying lengths made from hydrogen and carbon atoms only, joined together by covalent bonds. State why there is a need for cracking to be performed on. Cracking and alkenes crude oil, hydrocarbons and alkanes aqa. Alkanes have all cc single bonds and alkenes have cc double bond. Learn about fuels from crude oil with bitesize gcse combined science ocr gateway. The purpose of cracking is to produce high demand hydrocarbons. Petrol and other fuels are produced from it using fractional distillation.
An alkene is produced because the original alkane does not have enough hydrogen atoms to produce two more alkanes. This video prepares students for gcse higher tier science. The chemistry of cracking results in the formation of smaller, more useful alkanes such as petrol, and even more useful alkenes such as ethene. To compare and evaluate the conditions for and the products of thermal and catalytic cracking. Catalytic cracking takes place at a slight pressure, high temperature and in the presence of a zeolite catalyst and is used mainly to produce motor fuels and aromatic hydrocarbons mechanism not required. The viscosity of liquid alkanes increases as the number of carbon atoms increase. Thermo cracking is used to break down high molecular mass alkanes into low molecular mass alkanes as well as alkenes using heat and a catalyst.
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