Cracking a hydrocarbon produces two new hydrocarbons a and b. Cracking breaks longchain hydrocarbons into short chain hydrocarbons which are more useful. We also look at alkenes and how we test for alkenes using bromine water. This is achieved by using high pressures and temperatures without a catalyst, or lower temperatures and pressures in the presence of a catalyst. The cracking of hydrocarbons makes petrol and ethene. 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. Industrial processes such as cracking and reforming use these fractions to make hydrocarbons, which are in short supply. Cracking hydrocarbons edexcel gcse chemistry revision notes. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking paraffin. Cracking and alkenes crude oil, hydrocarbons and alkanes aqa.
First, crack the vapour of liquid paraffin by passing it over a heated catalyst to produce and collect a mixture of gaseous shortchain hydrocarbons. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Gcse chemistry crude oil and alkanes aqa 91 duration. The porous pot that is used in a lab, is used to facilitate the cracking process during heating, the porous pot is used as a catalyst to speed up the cracking process.
A brief description of the difference between thermal and catalytic cracking of alkanes. The mechanism of catalytic cracking of hydrocarbons is ionic. There is a greater demand for smaller hydrocarbons than larger ones. Catalytic cracking of hydrocarbons uniwersytet warszawski. Gcse chemistry what is the chemistry of the cracking of. Give an example of a method by which cracking can be carried out. Balance the equation for the complete combustion of this hydrocarbon. In this video, we look at how cracking is used to convert longchain hydrocarbons into shorterchain hydrocarbons. We crack alkanes because the shorter chain alkanes are more valuable they. The process is done at high temperature and pressure. Learn the basics about the cracking of hydrocarbons and why it is done. At fuse school, teachers and animators come together to make fun. Try this microscale approach it guarantees crack results every time.
This video prepares students for gcse higher tier science. When the hydrocarbon molecules are broken up in a random way as a product a mixture of shorter hydrocarbons chains is expected. This means that large hydrocarbon molecules break into smaller molecules when they are heated. Bromine water added to b turns from an orange solution to colourless. Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a. Written by teachers for the edexcel igcse chemistry course. Cracking is a thermal decomposition process by which large alkane hydrocarbon molecules are broken down by passing them over a heated catalyst at high pressure. Includes what cracking is and why it is useful, conditions for thermal and catalytic cracking, testing for alkenes and completing cracking equations. This resource is a lesson with activities covering the cracking hydrocarbons section of the 2015 aqa gcse chemistry specification. Chemistry revision notes on the topic cracking hydrocarbons. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits.
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 and alkenes crude oil, hydrocarbons and alkanes. Petrol and other fuels are produced from it using fractional distillation. Includes a couple of videos summarising the process cracking, and testing for alkenes. A hydrocarbons are broken down 1 mark to produce smaller more useful molecules 1 mark. Igcse chemistry past exams, tutorials, notes and more on nada ak is lecturing. A lesson covering cracking hydrocarbons as part of the organic chemistry unit key stage 4, aqa.
Why is porous pot catalyst used in cracking hydrocarbons. As well as alkanes, what other group of hydrocarbons are made as a result of cracking. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby. Polymers, monomers, crude oil, cracking and hydrocarbons. Take a look at our interactive learning flashcards about chemistry 5 cracking hydrocarbons gcse core, or create your own flashcards using our free cloud based flashcard maker. What is the chemistry of the cracking of hydrocarbons cracking of hydrocarbons involves thermal decomposition. Lesson with option of differentiated resources for cracking hydrocarbon fuelsfractions. During combustion, the and in the fuels are oxidised. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons.
In addition except, catalytic cracking reactions of isomeryzation, cyclization, polymerization, dehydrogenation and others are also possible. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Gcse chemistry what is the cracking of hydrocarbons. Gcse chemistry 6 cracking hydrocarbons no rude comments please. There are two good economic reasons for cracking oil fractions i there isn. You tend to get molecules containing benzene rings and short hydrocarbons. After the fractional distillation of crude oil there are too many large hydrocarbons and not enough small hydrocarbons to meet the publics demand. Norsk nynorsk polski portugues romana simple english slovencina slovenscina slunski. Apart from alkenes and alkanes what else is made during the process of cracking. Gcse chemistry revision science section covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single and double covalent bonds, and cracking paraffin. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too.
Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa. Top 5 college degrees that are actually worth it 2020 duration. Cracking is the process of converting alkanes into alkenes and shorter alkanes. Alkenes along with alkanes can be produced from cracking. The complete combustion of a hydrocarbon produces and. Are larger hydrocarbons more or less viscous than smaller hydrocarbons. Cracking is the name given to breaking up large hydrocarbon molecules into. Simply put, hydrocarbon cracking is the process of breaking a longchain of hydrocarbons into short ones. Products of cracking hydrocarbons the products of catalytic cracking include smaller alkanes and alkenes. Last time, i was looking at what features make up a letter, trying to define the ineffable qualities of letterness so that you arent relying on simply sticking an address at the beginning, along with a.
This lesson was originally designed for the aqa gcse 91 chemistry specification but is easily transferable to other specifications including ks3 as a challenge lesson and ks5 as a recap lesson. The hydrocarbons are boiled and the hydrocarbon gases are either mixed with steam and heated to a very high temperature or passed over a hot powdered aluminium. Ks4 aqa gcse chemistry science cracking hydrocarbons. Cracking hydrocarbons cracked to produce smaller more useful molecules. Petroleum as a source of hydrocarbons by fractional. Petroleum as a source of hydrocarbons by fractional distillation and cracking. Before joining or doing any activity please read the guidelines of the. Revision homework cracking hydrocarbons the production of some products of fractional distillation of crude oil, such as naphtha, fuel oil and bitumen, exceeds demand. Cracking hydrocarbons in liquid paraffin with a catalyst. Please comment if you have any questions, and subscribe if you. Cracking creates more useful hydrocarbons from less useful hydrocarbons by breaking down long chain alkanes into shorter chain molecules of alkane and alkene. Alkenes are a family of hydrocarbon compounds with the general formula c nh 2n, for example, c2h4 ethene.
Cracking breaks large hydrocarbon molecules down into smaller, more useful molecules. 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. Fractions containing large hydrocarbon molecules are. Cracking oil and cracking gcse chemistry single science. Designed by expert teachers for the edexcel gcse 91 chemistry syllabus. High octane starter to inject pace which is easily adapted for other lessons. Cracking hydrocarbon chains will be expected for all three exam boards which are aqa. Model the industrial process of cracking larger hydrocarbons to produce smaller alkanes that can be converted into petrol. Two methods of cracking how to write a balanced equation for cracking what an alkene is, and how they differ from an alkane the test for alkenes the.
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