Gcse chemistry what is the cracking of hydrocarbons. During the cracking process, hydrocarbons are first heated to vaporise them. A brief description of the difference between thermal and catalytic cracking of alkanes. The best way to remember the information in this chapter is to get a pen and paper and write down your answers. Galwey from the chemistry department, the queens university o belast, northern ireland received june 21, 1967. Cracking is the process whereby long and medium chain hydrocarbons are heated and break apart giving short chain alkanes, alkenes and hydrogen.
To aid your revision, have a go at this fun aqa syllabus a quiz and go over what you learned in year 10 and year 11. The purpose of this process is to get the simpler molecules from the complex organized molecules. Designed by expert teachers for the edexcel gcse 91 chemistry syllabus. Simply put, hydrocarbon cracking is the process of breaking a longchain of hydrocarbons into short ones. Compare the hydrocarbons in fractions d and f in terms of x boiling point x size of molecules x viscosity 3. Written by teachers for the edexcel igcse chemistry course. This is a thermal decomposition reaction known as cracking. Liquid paraffin a mixture of alkanes of chain length c20 and greater is vaporised and passed over a hot pumice stone catalyst. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a catalyst. 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.
Vladimir shukhov took the credit as the first person who invented and patented the cracking method in 1891. Facts about cracking hydrocarbons present the information about a process of cracking employed in the chemistry and petroleum geology. Crude oil is a mixture of compounds called hydrocarbons which are separated in a fractionating column. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too.
Cracking of ethane and propane to produce ethylene. Thermal cracking heats the naphtha fraction with steam at a high temperature about 800c and high pressure. 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. If the answer you have written is not right, change it. Apart from alkenes and alkanes what else is made during the process of cracking. 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. 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. Journal of catalysis 10, 277289 1968 hydrocarbon cracking reactions on nickel j.
Chemistry revision notes on the topic cracking hydrocarbons. Catalytic cracking processes heavy longchain fractions obtained in larger quantities than required. Cracking edexcel igcse chemistry notes save my exams. Crude oil is a dark smelly liquid which is a mixture of many different. This video prepares students for gcse higher tier science. Cracking and alkenes crude oil, hydrocarbons and alkanes aqa. This forms a mixture of straightchain alkanes and alkenes mainly ethene with a small proportion of branched and cyclic hydrocarbons. The petrochemical industry, the industrial production of ethene activity 2.
The process of cracking can be conducted on the long chain hydrocarbon. This is the first if six quizzes on that subject and it looks in particular at the hydrocarbons and alkanes which are found in crude oil. To find out the products formed when hydrocarbons burn, the apparatus below is used. There is a much greater demand for shorter hydrocarbon than there is for the longer hydrocarbons. To find out the products formed when hydrocarbons burn, the apparatus. Dec 31, 2015 summary video on cracking for gcse chemistry. Cracking hydrocarbon chains will be expected for all three exam boards which are.
A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. In all the following, students are required to apply or relate their understanding to a range of situations or scenarios. Chemistry crude oil aqa one of the topics covered in gcse science is the chemistry of crude oil and other fuels. These are the compounds of carbon and hydrogen found primarily in crude oil and used to make fuels. Crude oil hydrocarbons and alkanes aqa test questions. Petrol and other fuels are produced from it using fractional distillation. The names of these three states are shown in the boxes. This is the second of six quizzes on that subject and it looks specifically at hydrocarbons the compounds of carbon and hydrogen in crude oils.
A gaseous product is obtained which is flammable and which will. Cracking is used to make longchain hydrocarbon molecules into shorterchain. Oldsetaqa gcse chemistry topic 610 paper 2 quizlet. Cracking hydrocarbons edexcel gcse chemistry revision notes. It does not have any functional group, hence alkanes are quite inert in nature. Hydrocarbons from oil a2levellevelrevision, chemistry. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds alkenes. Have a go at this interactive aqa syllabus a quiz and revise what youve learned about their chemistry. During combustion, the and in the fuels are oxidised. Gcse fuel revision of hydrocarbon compounds in crude oil.
Free gcse chemistry science cracking hydrocarbons practice. Cracking produces shortchain hydrocarbons called alkanes, like petrol and alkenes, like ethene and propene. The name given to hydrocarbons with single bonds only is. 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. Mar 24, 2019 this resource is a broken down practice exam question to help improve exam technique when answering exam questions on cracking hydrocarbons. In this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkenes. Oldsetaqa gcse chemistry topic 610 paper 2 flashcards. These alkenes are very reactive due to their double bonds and therefore can be used to make other substances. Catalytic cracking breaks cc bonds by heterolytic fission forming ions. After the fractional distillation of crude oil there are too many large hydrocarbons and not enough small hydrocarbons to meet the publics demand. Hydrocarbon cracking reactions on nickel sciencedirect. C 5 h 10 the following formula satisfies the general formula of alkene and consists of 5 carbon atoms.
Naming an organic compound by interprating the formula. Are larger hydrocarbons more or less flammable than smaller hydrocarbons. Cracking and alkenes crude oil, hydrocarbons and alkanes. To do well in gcse science, year 10 and year 11 students will need to know what hydrocarbons and alkenes are. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. Past paper questions crude oil, fractional distillation. The petrochemical industry, pressure and steam in ethene production activity 3. Pressure and steam an interesting aspect of ethene production. Many of the substances with longer molecules produced from the fractional distillation of crude oil are cracked.
Give the name of a catalyst used in industry to crack longchain hydrocarbons and state a temperature at which cracking is carried out. Cracking is considered as a very important process for it can generate coke, gas oil and. Alkane is the simplest of all the homologous series. This is a gross oversimplification, and is written to satisfy the needs of one of the uk a level exam boards aqa. The name given to hydrocarbons with at least one double bond is. New91 aqa gcse chemistry c9 crude oil and fules kerboodle.
Cracking takes place at high temperatures as the large molecules pass over a catalyst. And be careful with your phrasing cracking produces alkenes and shorter chain alkanes. Theyre found in crude oil and have many uses, from fuel to construction materials. Fractions containing large hydrocarbon molecules are heated at 600 700c to vaporise them. Thermal cracking breaks cc bonds by homolytic fission forming free radicals. Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a process known as cracking. C 3 h 8 the following formula satisfies the general formula of alkane, and consists of 3 carbon atoms.
Cracking is the name given to breaking up large hydrocarbon molecules into. Give two examples of properties of hydrocarbons that are dependent upon the size of the hydrocarbon molecule. Best igcse organic chemistry notes complete breakdown. This page also contains the link to the notes and video for the revision of this topic c9. The name given to hydrocarbons with at least one triple bond is. Candidates should be able to make simple choices based upon the analysis and evaluation of information provided when. The alkane c 14h 30 might split in a variety of different ways. Please remember to leave feedback, for updates and promotions you can also follow me here. Cracking is a form of thermal decomposition, which breaks long chain hydrocarbons, many of which are not very useful, into shorter molecules by heating them. Gcse chemistry products from oil medium demand questions questionsheet 14 some of the products of the distillation of crude oil are used as fuels. The simplest alkenes have the general formula c n h 2n. Crude oil hydrocarbons and alkanes aqa test questions aqa. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Learn the basics about the cracking of hydrocarbons and why it is done.
Gcse triple chemistry revision topic 10 using resources questions and answers. Subject contents for the 6 important sections discussed above for 0620 igcse chemistry past year papers. Ethene c 2 h 4 is an example of a family of hydrocarbons called the alkenes. Gcse chemistry revision questions fossil fuels crude. Write equations for the cracking of c 14h 30 which lead to the. Cracking oil and cracking gcse chemistry single science. Apparatus delivery tube and bung bunsen burner boiling tube containing mineral wool porous pot liquid paraffin clamp and stand. It only has simple ch bonds throughout its whole structure. Vapours will then pass over a hot catalyst of silica. Chemistry hydrocarbons and fuels aqa in gcse science one topic studied is crude oil and other types of fuel. You need to know about alkanes, alkenes, crude oil and the process of cracking. The nobel school, stevenage, mobbsbury way, sg2 0hs phone.
Crude oil is described as a fossil fuel but it is much more important than that as many plastics have crude oil as a raw material. C 3 h 7 oh the following is an alcohol as we can see a oh group is attached to it, with three. One of the topics studied in the chemistry section of gcse science is hydrocarbons. 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. Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa.
Alkenes along with alkanes can be produced from cracking. Petroleum as a source of hydrocarbons by fractional distillation and cracking. For example, butane is an alkane with four carbon atoms. One of the byproducts of this thermal decomposition reaction is ethene. Ethene, for example can be used to make ethanol and polythene. Complete the sentences using the words in the boxes. Free gcse chemistry science cracking hydrocarbons practice exam question. Start studying oldsetaqa gcse chemistry topic 610 paper 2.
53 1510 387 827 1557 357 1026 52 187 875 1366 1367 745 418 301 984 412 159 918 348 396 1523 681 978 549 1399 1572 1275 1076 1414 193 451 920 724 1063 1350