The gaseous and residual soluble hydrocarbons were analyzed. Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. Cracking the hydrocarbons in paraffin to form shorter alkanes and alkenes can be done as a class practical. Some of the large hydrocarbons the heavier fractions are broken down into more useful smaller hydrocarbons lighter fractions by a process known as cracking. The worksheet can also be found by clicking on the worksheet below. 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 chemistry of cracking results in the formation of smaller, more useful alkanes such as petrol. It also produces high proportions of branched alkanes and aromatic hydrocarbons like benzene. The petrochemical industry, the industrial production of ethene activity 2. Cracking and alkenes crude oil, hydrocarbons and alkanes. In the absence of oxygen, h 2 produced by methane cracking is free of co and co 2, making methane cracking a suitable method to produce h 2 for fuel cells which require. Theyre found in crude oil and have many uses, from fuel to construction materials.
Please comment if you have any questions, and subscribe if you. The results show that the cracking of oil to gas can be divided into two distinct stages. Cracking hydrocarbons edexcel gcse chemistry revision notes. A fractional distillation b cracking c crude oil extraction.
Alternatively, we can mix the hydrocarbon vapor with very hot steam. Cracking hydrocarbons on a microscale resource rsc. First, crack the vapour of liquid paraffin by passing it over a heated catalyst to produce and collect a mixture of gaseous shortchain hydrocarbons. However, safety concerns by many teachers and availability of equipment in some schools mean that this key and interesting experiment is often done as a demonstration.
Cracking hydrocarbons in liquid paraffin with a catalyst. Petrol and other fuels are produced from it using fractional distillation. Cracking produces smaller hydrocarbons, smaller hydrocarbons have greater demand, they are easier to burn, and also cracking produces more reactive alkenes. Making crude oil usefulfractional distillation and cracking. A microscale experiment, cracking the hydrocarbons in paraffin to form shorter alkanes and alkenes.
Hydrocarbons from oil a2levellevelrevision, chemistry. I saw an example of cracking hexane and decane and one of the products of both was always ethene. Cracking creates more useful hydrocarbons from less useful hydrocarbons by breaking down long chain alkanes into shorter chain molecules of alkane and alkene. How does it work why is crude oil both important and useless. All that we need to do is heat longchain hydrocarbons, so that they turn into vapor. Cracking cracking is the breaking down of an unsaturated hydrocarbon into smaller hydrocarbons.
There is a greater demand for smaller hydrocarbons than larger ones. Best igcse organic chemistry notes complete breakdown. Ethene c 2 h 4 is an example of a family of hydrocarbons called the alkenes. The process also results in the slow deposition of coke, a form of carbon, on the reactor walls. Modern living is built on crude oil this hub explains how crude oil is changed into the things we use everyday, from petrol to plastic.
Facts about cracking hydrocarbons present the information about a process of cracking employed in the chemistry and petroleum geology. The purpose of this process is to get the simpler molecules from the complex organized molecules. Cracking converts long chain hydrocarbons into short chain hydrocarbons. The purpose of cracking is to produce high demand hydrocarbons. It is caused by the breaking of carboncarbon bonds. New gcse chemistry 2016 history of periodic table, full lesson resource pack gcse. Gcse chemistry what is the chemistry of the cracking of. We then pass the vapor over a hot catalyst, to speed up the reaction.
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. These are the compounds of carbon and hydrogen found primarily in crude oil and used to make fuels. During cracking, hydrocarbons are often passed over a substance so that they break apart. Model the industrial process of cracking larger hydrocarbons to produce smaller alkanes that can be converted into petrol. Another method of cracking hydrocarbons uses steam. I need to answer the following questions about the experiment for cracking hydrocarbons, using paraffin and porcelain as a catalyst. To do well in gcse science, year 10 and year 11 students will need to know what hydrocarbons and alkenes are. The alkane c 14h 30 might split in a variety of different ways. Crude oil and hydrocarbons crude oil, hydrocarbons and. Cracking is used to make longchain hydrocarbon molecules into shorterchain. One of the topics studied in the chemistry section of gcse science is hydrocarbons. One of the byproducts of this thermal decomposition reaction is ethene. High octane starter to inject pace which is easily adapted for other lessons. Cracking also produces alkenes which are used in making polymers and ethanol.
A brief description of the difference between thermal and catalytic cracking of alkanes. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a catalyst. This lesson is designed for the new aqa trilogy chemistry gcse, particularly the organic chemistry sow. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too. As a result, cracking produces smaller alkanes and alkenes. The process is done at high temperature and pressure. How science works quiz definitions quiz introduction quiz variables quiz types of variables quiz planning quiz results table quiz graph. But in crude oil, there are not enough fraction of the lighter hydrocarbons to provide for this demand. To fulfill this high demand, the larger fractions of. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes. Try this microscale approach it guarantees crack results every time. Gcse fuel revision of hydrocarbon compounds in crude oil. The rate of catalyst greatly depends upon the factors such as the presence of catalyst and temperature.
In the petroleum industry, large hydrocarbons from the distillation of crude oil are often cracked to split them into smaller bits. It is the principal industrial method for producing lighter alkenes olefins, including ethene or ethylene and propene or propylene figure 3. Learn about fuels from crude oil with bitesize gcse combined science ocr gateway. As part of their work on crude oil, gcse chemistry students will look at thermal cracking. Common igcse chemistry exam questions with answers igcse. While the gas feedstock for methane cracking is mainly composed of ch 4, other hydrocarbons present are cracked in the same way as ch 4 by thermal splitting of the c h bonds. An alkene is produced because the original alkane does. Gcse chemistry revision science section covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single and double covalent bonds, and cracking paraffin. Cracking meaning types of cracking organic chemistry.
This results in the breaking of the covalent bonds in the hydrocarbon molecules. Why do long hydrocarbons have higher boiling points. There is a very high demand for lighter hydrocarbons such as petrol because they burn easily. Shorter chain hydrocarbons are in greater demand, e.
Advanced aas level chemistry us k12 grades 1112 pre university, gcse 91. 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. A cracking practical can be carried out in a school lab quite easily by using a broken pottery as a catalyst. Petroleum as a source of hydrocarbons by fractional. The simplest alkenes have the general formula c n h 2n. Well email you at these times to remind you to study. Have a go at this interactive aqa syllabus a quiz and revise what youve learned about their chemistry. The process of cracking sometimes involves vapourising the hydrocarbons and then mixing the vapours with. The molecules are broken up in a random way which produces a mixture of alkanes. Gcse chemistry what is the cracking of hydrocarbons.
Cracking oil fractions reaction conditions products equations. Give the name of a catalyst used in industry to crack longchain hydrocarbons and state a temperature at which cracking is carried out. Cracking takes place at high temperatures as the large molecules pass over a catalyst. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. The name given to hydrocarbons with single bonds only is. The process whereby catalysts are added to certain hydrocarbons in order to break them into smaller hydrocarbons suitable for petrol and plastics is called. Cracking and alkenes crude oil, hydrocarbons and alkanes aqa. Methane cracking as a bridge technology to the hydrogen. The process of cracking can be conducted on the long chain hydrocarbon. I print the starter as as handout sheet so they only have to complete the cloze exercise without writing everything. You can find instructions for this experiment at resourceres00000681crackinghydrocarbons liquid paraffin. 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. They react because sio 2 is acidic while cao is basic.
For example, a higher hydrocarbon c 1 0 h 2 2 splits according to the reaction. Learn about crude oil, hydrocarbons and alkanes with bitesize gcse chemistry aqa. Cracking is the name for a thermal decomposition processes. The nobel school, stevenage, mobbsbury way, sg2 0hs phone. This is a dangerous scientific experiment and must not be attempted without skilled supervision. What is the name of the process by which large hydrocarbons are broken up into smaller, more useful molecules. Ethene is made by cracking saturated hydrocarbons from crude oil. Cracking of ethane and propane to produce ethylene. The fractions, containing gaseous hydrocarbon molecules, are mixed with steam and heated to very high temperatures over 800. Cracking hydrocarbons in liquid paraffin with a catalyst resource. Cracking is the name given to breaking up large hydrocarbon molecules into. A higher cracking temperature also referred to as severity favors the production of ethene and benzene, whereas lower severity produces higher amounts of propene, c4hydrocarbons and liquid products. The zeolites used in catalytic cracking are chosen to give high percentages of hydrocarbons with between 5 and 10 carbon atoms particularly useful for petrol gasoline.
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