The complete combustion of a hydrocarbon produces and. The fractional distillation of crude oil produces alkanes. Structure, formula and reactions of alkenes chemistry only 1. Firstly, students asked to think about a question that oil companies face what to do with longer chain hydrocarbons which are in less demand than smaller chain hydrcarbons. Cracking oil fraction hydrocarbons to produce more useful products. During cracking, hydrocarbons are often passed over a substance so that they break apart. Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules. This summarises the key topics for the organic chemistry unit, including crude oil, the structure of alkanes, fractional distillation, properties of hydrocarbons, cracking, alkenes and polymerization. You could dismiss the other three answers because at gcse, you are expected to know that the products of thermal cracking of an alkane will produce only a shorter chain alkane and an alkene so any answer containing other products, like carbon dioxide and hydrogen, are false. Alkenes along with alkanes can be produced from cracking.
One of the products of cracking this compound is an alkane which has 10 carbon atoms in it. Petrol and other fuels are produced from it using fractional distillation. What is the cracking of hydrocarbons after the fractional distillation of crude oil there are too many large hydrocarbons and not enough small hydrocarbons to meet the publics demand. Chemistry 5 cracking hydrocarbons gcse core flashcards. Fractions containing large hydrocarbon molecules are heated to vaporise them. Gcse chemistry what is the cracking of hydrocarbons. This is an uncatalysed method of breaking down the hydrocarbons. Hydrocarbons can be broken down cracked to produce smaller, more useful molecules. Below is a valuable list of all the gcse chemistry topics students could be tested on. What is the chemistry of the cracking of hydrocarbons. Cracking is defined as a process, wherein complex organic molecules namely long chain hydrocarbons or kerogens are broken down into smaller molecules namely light hydrocarbons. Doc browns gcseigcseo level ks4 sciencechemistry revision notes.
Gcse chemistry revision science section covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single and double covalent bonds, and cracking paraffin. Gcse crude oil revise the thermal cracking reaction. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or longchain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carboncarbon bonds in the precursors. Hydrocarbons from oil a2levellevelrevision, chemistry. Cracking is the name for a thermal decomposition processes. Thermal cracking heats the naphtha fraction with steam at a high temperature about 800c and high pressure. Cracking allows large hydrocarbon molecules to be broken down into smaller. Please comment if you have any questions, and subscribe if you. In order to perform to the best of your ability in the exam, you need to have a good understanding of the topics covered in the tests. We can break down hydrocarbons in a process called cracking. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits. Gcse chemistry flashcards on chemistry 5 cracking hydrocarbons gcse core, created by chloe roberts on 25042014. New91 aqa gcse chemistry c9 crude oil and fules kerboodle. For example, a higher hydrocarbon c 1 0 h 2 2 splits according to the reaction.
This page contains the aqa gcse chemistry c9 hydrocarbons questions and kerboodle answers for revision and understanding hydrocarbons. Give the general formula of the alkenes and explain why they are called unsaturated. The complete series covers the aqa gcse 91 chemistry 8462 and combined science trilogy 8464 specifications for chemistry. This resource is a lesson with activities covering the cracking hydrocarbons section of the 2015 aqa gcse chemistry specification. Chemistry paper 2 organic chemistry crude oil and hydrocarbons. Reforming is described as the processing of straightchain hydrocarbons into branchedchain alkanes and cyclic hydrocarbons for efficien gcse. It is caused by the breaking of carboncarbon bonds. Revise and summarise the key information for unit 7. Do not forget the word only at the end since crude oil is a mixture of different hydrocarbon compounds. Liquid paraffin a mixture of alkanes of chain length c20 and greater is vaporised and passed over a hot pumice stone catalyst. Apart from alkenes and alkanes what else is made during the process of cracking.
Bp educational service hydrocarbons from crude oil. Resources chemistry gcse aqa unit 8 crude oil and fuels. Includes what cracking is and why it is useful, conditions for thermal and catalytic cracking, testing for alkenes and completing cracking equations. May 22, 2012 for double award you only need to know the haber process, single award people, you also need to know the contact process for the manufacture of sulphuric acid. A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. Organic chemistry i study guide by drmeally includes 42 questions covering vocabulary, terms and more. Fuels made from oil mixtures containing large hydrocarbon. This page also contains the link to the notes and video for the revision of this topic c9. Crude oil is a mixture of substances which are mostly hydrocarbons a hydrocarbon is a compound containing hydrogen and carbon only remember the above sentence, you will probably need it in the exam. Cracking is normally carried out at high temperatures using a catalyst.
Cracking of hydrocarbons is illustrated in the below diagram. C 16 h 34 is an alkane which can be used as the starting chemical in cracking. Short, engaging multimedia learning materials on the topic of hydrocarbons from crude oil, putting science in a reallife context. Includes a couple of videos summarising the process cracking, and testing for alkenes.
The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. We have placed cookies on your computer to help make this website better. Complete the sentences using the words in the boxes. Cracking hydrocarbons in liquid paraffin with a catalyst resource. Cracking is the most important process for the commercial production of gasoline and diesel fuel. By heating them with steam to a very high temperature or by passing. Cracking and alkenes crude oil, hydrocarbons and alkanes.
A lesson covering cracking hydrocarbons as part of the organic chemistry unit key stage 4, aqa. Cracking is used to convert long alkanes into shorter, more useful 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. The fractions, containing gaseous hydrocarbon molecules, are mixed with steam and heated to very high temperatures over 800. Choose from 500 different sets of gcse chemistry alkanes flashcards on quizlet. Gcse chemistry what is the chemistry of the cracking of. Designed by expert teachers for the edexcel gcse 91 chemistry syllabus. Balance the equation for the complete combustion of this hydrocarbon. There is a greater demand for smaller hydrocarbons than larger ones.
Cracking is important because cracking produces shorter chain saturated hydrocarbons which are more in demand as fuel and unsaturated hydrocarbon which is used in polymer synthesis. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds alkenes. Cracking hydrocarbons in liquid paraffin with a catalyst. Learn gcse chemistry alkanes with free interactive flashcards. Crude oil is a dark smelly liquid which is a mixture of many different. In this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. There is a high supply but low demand of long chain hydrocarbons. 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. Alkenes are a family of hydrocarbon compounds with the general formula c nh 2n, for example, c2h4 ethene.
The unit then moves onto the alkenes as a different homologous series from the alkanes, together with a consideration of the cracking process. Alternatively, we can mix the hydrocarbon vapor with very hot steam. Studying chemistry at gcse helps to explain these and many other interactions. During combustion, the and in the fuels are oxidised. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking paraffin. This forms a mixture of straightchain alkanes and alkenes mainly ethene with a small proportion of branched and cyclic hydrocarbons. Organic chemistry from the combined science aqa gcse chemistry specification. All that we need to do is heat longchain hydrocarbons, so that they turn into vapor. Products of cracking hydrocarbons the products of catalytic cracking include smaller alkanes and alkenes. The chemistry of cracking links hydrocarbons revision questions. Chemistry revision notes on the topic cracking hydrocarbons. Cracking ensures that there is a good supply of short chain alkanes. Cracking hydrocarbons edexcel gcse chemistry revision notes. We will discuss their general formula, physical and chemical properties.
Gcse science chemistry 91 crude oil and hydrocarbons. Your students can be examready with this fantastic resource. There is a much greater demand for shorter hydrocarbon than there is for the longer hydrocarbons. Aug 22, 2019 this lesson is designed for the new aqa trilogy chemistry gcse, particularly the organic chemistry sow. Ks4 aqa gcse chemistry science cracking hydrocarbons. The longchain hydrocarbon alkane molecules are passed over a catalyst either silica or aluminium oxide heated to about 600700 c. The rate of catalyst greatly depends upon the factors such as the presence of catalyst and temperature. Cracking larger hydrocarbons produces smaller alkanes that can be converted into petrol. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a catalyst. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too. Model the industrial process of cracking larger hydrocarbons to produce smaller.
Cracking hydrocarbons on a microscale resource rsc education. Cracking, in petroleum refining, the process by which heavy hydrocarbon molecules are broken up into lighter molecules by means of heat and usually pressure and sometimes catalysts. Organic chemistry is the study of compounds based on hydrocarbons and their derivatives. Gcse chemistry aqa 91 organic chemistry alkanes and alkenes. Give an example of a method by which cracking can be carried out. The chemistry of cracking results in the formation of smaller, more useful alkanes such as petrol, and even more useful alkenes such as ethene. Cracking oil and cracking gcse chemistry single science. If the answer you have written is not right, change it. Alkenes are hydrocarbons with a double carbon carbon bond. Best igcse organic chemistry notes complete breakdown.
Gcse science chemistry 91 crude oil and hydrocarbons duration. Start studying gcse chemistry aqa 91 organic chemistry alkanes and alkenes. Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa. Learn the basics about the cracking of hydrocarbons and why it is done. Cracking breaks longchain hydrocarbons into short chain hydrocarbons which are more useful. Cracking meaning types of cracking organic chemistry. Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a process known as cracking. We then pass the vapor over a hot catalyst, to speed up the reaction.
This means that large hydrocarbon molecules break into smaller molecules when they are heated. In chemistry, it is a process of breaking down large alkane into simpler alkenes and alkanes. It also produces small alkenes, which are used make many other useful organic chemicals petrochemicals, especially plastics. Schematic diagram of a fluid catalytic cracking unit. This organic chemistry note for igcse chemistry will cover the three major homologous series alkane, alkene, and alcohols. This lesson is designed for the new aqa trilogy chemistry gcse, particularly the organic chemistry sow. Cracking and alkenes gcse chemistry single science revision. Give two examples of properties of hydrocarbons that are dependent upon the size of the hydrocarbon molecule. In petroleum refining, this process is used in the production of petrol, diesel, and gasoline. Chemistry hydrocarbons, fractional distillationl, uses and cracking of crude oil, alkenes and their reactions. This results in the breaking of the covalent bonds in the hydrocarbon molecules. Written by teachers for the edexcel igcse chemistry course.
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