Organic chemistry is the study of compounds based on hydrocarbons and their derivatives. Learn gcse chemistry alkanes with free interactive flashcards. 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. Cracking hydrocarbons in liquid paraffin with a catalyst.
There is a much greater demand for shorter hydrocarbon than there is for the longer hydrocarbons. Includes a couple of videos summarising the process cracking, and testing for alkenes. The fraction produced from crude oil is heated to form a gas. Short, engaging multimedia learning materials on the topic of hydrocarbons from crude oil, putting science in a reallife context. Start studying gcse chemistry aqa 91 organic chemistry alkanes and alkenes. Give the general formula of the alkenes and explain why they are called unsaturated. A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. C 16 h 34 is an alkane which can be used as the starting chemical in cracking. This resource is a lesson with activities covering the cracking hydrocarbons section of the 2015 aqa gcse chemistry specification. The complete combustion of a hydrocarbon produces and. Cracking is normally carried out at high temperatures using a catalyst. Cracking oil and cracking gcse chemistry single science. Alkenes are hydrocarbons with a double carbon carbon bond.
The process of breaking higher hydrocarbons with high boiling points into a variety of lower hydrocarbons that are more volatile low boiling, is called cracking or pyrolysis. Cracking hydrocarbons in liquid paraffin with a catalyst resource. Do not forget the word only at the end since crude oil is a mixture of different hydrocarbon compounds. Includes what cracking is and why it is useful, conditions for thermal and catalytic cracking, testing for alkenes and completing cracking equations. Give an example of a method by which cracking can be carried out. Revise and summarise the key information for unit 7. Cracking ensures that there is a good supply of short chain alkanes. Below is a valuable list of all the gcse chemistry topics students could be tested on. The fractions, containing gaseous hydrocarbon molecules, are mixed with steam and heated to very high temperatures over 800. One of the products of cracking this compound is an alkane which has 10 carbon atoms in it. Gcse chemistry aqa 91 organic chemistry alkanes and alkenes. Best igcse organic chemistry notes complete breakdown.
Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a process known as cracking. Studying chemistry at gcse helps to explain these and many other interactions. Give two examples of properties of hydrocarbons that are dependent upon the size of the hydrocarbon molecule. Cracking allows large hydrocarbon molecules to be broken down into smaller. Schematic diagram of a fluid catalytic cracking unit.
Organic chemistry from the combined science aqa gcse chemistry specification. 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. We then pass the vapor over a hot catalyst, to speed up the reaction. Cracking and alkenes crude oil, hydrocarbons and alkanes. Aug 22, 2019 this lesson is designed for the new aqa trilogy chemistry gcse, particularly the organic chemistry sow. 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. For example, a higher hydrocarbon c 1 0 h 2 2 splits according to the reaction. This page also contains the link to the notes and video for the revision of this topic c9. Fractions containing large hydrocarbon molecules are heated to vaporise them. The fractional distillation of crude oil produces alkanes. Apart from alkenes and alkanes what else is made during the process of cracking. 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.
Designed by expert teachers for the edexcel gcse 91 chemistry syllabus. Complete the sentences using the words in the boxes. Cracking larger hydrocarbons produces smaller alkanes that can be converted into petrol. Gcse science chemistry 91 crude oil and hydrocarbons. In thermal cracking, high temperatures typically in the range of 450c to 750c and pressures up to about 70 atmospheres are used to break the large hydrocarbons into smaller ones. 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. Chemistry 5 cracking hydrocarbons gcse core flashcards. Balance the equation for the complete combustion of this hydrocarbon. Cracking hydrocarbons on a microscale resource rsc education. Gcse crude oil revise the thermal cracking reaction. 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. If the answer you have written is not right, change it.
There is a high supply but low demand of long chain 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 complete series covers the aqa gcse 91 chemistry 8462 and combined science trilogy 8464 specifications for chemistry. Hydrocarbons from oil a2levellevelrevision, chemistry. Thermal cracking heats the naphtha fraction with steam at a high temperature about 800c and high pressure. Alkenes are a family of hydrocarbon compounds with the general formula c nh 2n, for example, c2h4 ethene. Doc browns gcseigcseo level ks4 sciencechemistry revision notes. Alternatively, we can mix the hydrocarbon vapor with very hot steam. Choose from 500 different sets of gcse chemistry alkanes flashcards on quizlet. We have placed cookies on your computer to help make this website better. It is caused by the breaking of carboncarbon bonds. 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.
Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules. Petrol and other fuels are produced from it using fractional distillation. Structure, formula and reactions of alkenes chemistry only 1. Gcse chemistry flashcards on chemistry 5 cracking hydrocarbons gcse core, created by chloe roberts on 25042014. Organic chemistry i study guide by drmeally includes 42 questions covering vocabulary, terms and more. What is the chemistry of the cracking of hydrocarbons. We will discuss their general formula, physical and chemical properties. Products of cracking hydrocarbons the products of catalytic cracking include smaller alkanes and alkenes. This organic chemistry note for igcse chemistry will cover the three major homologous series alkane, alkene, and alcohols. There is a greater demand for smaller hydrocarbons than larger ones.
Fuels made from oil mixtures containing large hydrocarbon. 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. Please comment if you have any questions, and subscribe if you. Cracking oil fraction hydrocarbons to produce more useful products. By heating them with steam to a very high temperature or by passing. Liquid paraffin a mixture of alkanes of chain length c20 and greater is vaporised and passed over a hot pumice stone catalyst. Cracking and alkenes gcse chemistry single science revision. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a catalyst. 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. Resources chemistry gcse aqa unit 8 crude oil and fuels. Hydrocarbons can be broken down cracked to produce smaller, more useful molecules. Chemistry paper 2 organic chemistry crude oil and hydrocarbons. In this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. During cracking, hydrocarbons are often passed over a substance so that they break apart.
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. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds alkenes. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. Crude oil is a dark smelly liquid which is a mixture of many different. The longchain hydrocarbon alkane molecules are passed over a catalyst either silica or aluminium oxide heated to about 600700 c. The chemistry of cracking links hydrocarbons revision questions. Gcse science chemistry 91 crude oil and hydrocarbons duration. Gcse chemistry what is the cracking of hydrocarbons. This results in the breaking of the covalent bonds in the hydrocarbon molecules.
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. In petroleum refining, this process is used in the production of petrol, diesel, and gasoline. All that we need to do is heat longchain hydrocarbons, so that they turn into vapor. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking paraffin. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too. New91 aqa gcse chemistry c9 crude oil and fules kerboodle.
During combustion, the and in the fuels are oxidised. We can break down hydrocarbons in a process called cracking. Alkenes along with alkanes can be produced from cracking. Model the industrial process of cracking larger hydrocarbons to produce smaller. 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.
Cracking is the most important process for the commercial production of gasoline and diesel fuel. Written by teachers for the edexcel igcse chemistry course. Learn the basics about the cracking of hydrocarbons and why it is done. Cracking of hydrocarbons involves thermal decomposition. The rate of catalyst greatly depends upon the factors such as the presence of catalyst and temperature. Cracking meaning types of cracking organic chemistry. It also produces small alkenes, which are used make many other useful organic chemicals petrochemicals, especially plastics. Gcse chemistry what is the chemistry of the cracking of.
Chemistry hydrocarbons, fractional distillationl, uses and cracking of crude oil, alkenes and their reactions. Reforming is described as the processing of straightchain hydrocarbons into branchedchain alkanes and cyclic hydrocarbons for efficien gcse. This lesson is designed for the new aqa trilogy chemistry gcse, particularly the organic chemistry sow. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits.
Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa. The chemistry of cracking results in the formation of smaller, more useful alkanes such as petrol, and even more useful alkenes such as ethene. This forms a mixture of straightchain alkanes and alkenes mainly ethene with a small proportion of branched and cyclic hydrocarbons. 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. This is an uncatalysed method of breaking down the hydrocarbons. Ks4 aqa gcse chemistry science cracking hydrocarbons. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Your students can be examready with this fantastic resource. Bp educational service hydrocarbons from crude oil. Cracking hydrocarbons edexcel gcse chemistry revision notes. The unit then moves onto the alkenes as a different homologous series from the alkanes, together with a consideration of the cracking process. Chemistry revision notes on the topic cracking hydrocarbons. Cracking is the name for a thermal decomposition processes.