Addition polymerisation gcse chemistry 9 1 youtube. These long chain molecules can be made up from tens of thousands of monomers joined together. So heavy hydrocarbon molecules are broken up into lighter molecules. As 90698 describe aspects of organic chemistry collated polymer questions polyesters, polyamides and peptides 2011. Parents students tutors teachers knowledge bank survey results. Gcse chemistry what is the chemistry of the cracking of. 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. Polymerization begins at the initiator, and reaction continues until there are no more monomers to add to the growing polymer chain.
Today students across england, wales and northern ireland have received their gcse examination results. To familiarise you with it, weve created this interactive quiz. You can shortcut the process by adding other organic peroxides directly to the ethene instead of using oxygen if you want. In condensation polymerization, each step of the process is accompanied by the formation of a molecule of some simple compound, often water. Oct 03, 2015 a short videoaudio guide explaining the essentials of cracking and polymerization. In polymer chemistry, polymerization is a process of reacting monomer molecules. Cracking hydrocarbons edexcel gcse chemistry revision notes. Addition polymerization takes place when the monomer molecule contains double carbon bonds, as in alkenes, or triple carbon bonds, as in alkynes. It does not have any functional group, hence alkanes are quite inert in nature. Crude oil is a finite resource that is found in the earths crust. Science gcse results in 2017, compared with previous years science gcse results in 2017, compared with previous years. Organic peroxides are very reactive molecules containing oxygenoxygen single bonds which are quite weak and which break easily to give free radicals.
Others such as branched and cyclic alkanes are added to the gasoline fraction obtained from the distillation of crude oil to enhance the octane rating. Condensation polymerisation involves a reaction between monomers with two different functional groups. Cracking of hydrocarbons involves thermal decomposition. Gcse crude oil revise the thermal cracking reaction. Index of oil and organic chemistry gcseigcseo level revision. The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Polymerisation happens when monomers react to form long chain polymer molecules. In condensation polymerisation, a small molecule is formed as a byproduct each time a bond is formed between two monomers. Targeted towards aqa c1 topic 5 but suitable for edexcel and other exam boards too. Difference between thermal cracking and catalytic cracking. Basics of organic chemistry practice test questions. Click on the button below to view the simulation window. Please comment if you have any questions, and subscribe if you.
Poly ethene is a polymer made from a very large number of ethene molecules combined together. Polymers are large molecules that are made up of many repeated small molecules. Cracking molecules and plastics chemistry gcse ask. How students are looking after their mental health in lockdown. Each polymer molecule is a long chain of mainly carbon atoms.
Index of notes on the oil industry and organic chemistry. As you can see in the video opposite, cracking needs a catalyst and a high temperature. Some are common sense but make sure to test yourself afterward as at least 10 marks in every test will go to definitions. Making crude oil usefulfractional distillation and cracking. This is because alkanes are saturated whereas alkenes are unsaturated which means that they can carry out addition reactions, required for polymerisation. It helps to match the supply of fractions with the demand for them. Catalytic cracking process was invented by eugene houdry in 1937. Benzene or chlorobenzene is used as the solvent since both polymer polythene and monomer ethene dissolve in these compounds at the temperature and pressure used. Water or other liquids may be added to dissipate the heat of reaction as the polymerization reaction is highly exothermic. 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. When these types of monomers react they join together, usually losing a small molecule such as water, and so the reactions are called condensation reactions. For example, ethene molecules can react together to. Polymers are very large molecules sometimes called macromolecules. Addition polymerizations usually are carried out in the presence of catalysts, which in certain cases exert control over structural details that have important effects on the properties of the polymer.
Basics of organic chemistry chapter exam instructions. Sep 27, 2017 in liquid phase catalytic cracking, the reaction mixture is maintained at a temperature of about 500 o c and 20 atm pressure. A monomer is the building block or in other words the repeating unit that is used to make the polymer. A monomer is a small reactive molecule that can be joined with other monomers to form long chains. This page contains the aqa gcse chemistry polymers questions and kerboodle answers for revision and understanding polymers. These monomers the starting materials are often alkenes. Naming an organic compound by interprating the formula. It produces alkenes, which are useful as feedstock for the petrochemical industry. In addition polymerization, monomers react to form a polymer without the formation of byproducts. C 3 h 7 oh the following is an alcohol as we can see a oh group is attached to it, with three.
Many small individual molecules, called monomers, are joined up to form a polymer. Gcse chemistry revision covering cracking and its products, hydrocarbons, catalyst, thermal decomposition, alkanes, single covalent bonds, alkenes, double covalent bonds, and cracking paraffin. Polythene polyethene is made by forming a long chain of ethene molecules. This is achieved by using high pressures and temperatures without a catalyst, or lower temperatures and pressures in the presence of a catalyst. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a catalyst. Wellcome would like to congratulate all the students receiving science, maths and computing gcses and the teachers who have inspired them.
Jun 15, 2016 cracking converts large alkane molecules into smaller, more useful, alkane and alkene molecules. Cracking is the term when a long unuseful molecule like bitumen are broken down into short more useful molecules like petrol. C 5 h 10 the following formula satisfies the general formula of alkene and consists of 5 carbon atoms. Other articles where addition polymerization is discussed. Polymerization, any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. The starter is a dingbat that is shown whilst students listen to music to help them. In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby. One of the topics covered in gcse chemistry is polymerisation. Cracking fractional distillation gcse chemistry single science. Silica or related compounds are often used as the catalyst.
Cracking is the most important process for the commercial production of gasoline and diesel fuel. The initial step involves the cleavage of a c c bond or a c h bond leading to the formation of free radicals. Organic chemistry introduction 1 structural formulae. Alkenes can take part in reactions that alkanes cannot. Cracking allows large hydrocarbon molecules to be broken down into smaller, more. The similar electronegativities of carbon and hydrogen give molecules which are nonpolar. Alkane is the simplest of all the homologous series. Cracking and alkenes crude oil, hydrocarbons and alkanes. They are made of small building blocks called monomers. An example of alkene polymerization, in which each styrene monomers double bond reforms as a single bond plus a bond to another styrene monomer. The alkenes can then undergo polymerisation to make polymers such as plastics while the shorter alkanes are typically used for fuel. Usually at least 100 monomer molecules must be combined to make a product that has certain unique physical properties.
A short videoaudio guide explaining the essentials of cracking and polymerization. Fractional distillation is a process by which components in a chemical mixture are separated into different parts called fractions according to their different boiling points. The end result is in smaller hydrocarbon molecules. Cracking is conducted at high temperatures, by two processes. Cracking oil fractions reaction conditions products equations. This type of polymerisation is called addition polymerisation. But when some of the fractions of crude oil are cracked, a whole new world of chemistry opens up. This is done by means of heat, pressure, and sometimes catalysts. Fractional distillation is used to purify chemicals and to separate mixtures to obtain their components. Propagation of the chain mechanism occurs by several different radical. It is the principal industrial method for producing lighter alkenes olefins, including ethene or ethylene and propene or propylene figure 3. Gcse polymerisation revise reaction of monomer molecules.
Thermal cracking was invented in 1930 by william meriam burton. An explanation of addition polymerisation for gcse chemistry 9 1. Alkanes contain only ch and cc bonds, which are relatively strong and difficult to break. Addition polymerizations usually are carried out in the presence of catalysts. What is a polymer polymers are very large molecules sometimes called macromolecules. Polymerisation is the name given to the reaction that produces polymers. Each polymer molecule is a long chain of mainly carbon atoms polymers are made from many smaller molecules, called monomers. The cc double bond in ethene is involved in the polymerisation reaction.
It only has simple ch bonds throughout its whole structure. Three pupils from moulsham high school in chelmsford, essex, open their gcse results live on itvs good morning britain on thursday. Polymers are made from many smaller molecules, called monomers. Remember, dont rely on remembering them in the order they appear below as this will not be like an exam. Chemistry gcse results for 2016, compared to previous years chemistry gcse results for 2016, compared to previous years. Chemistry gcse results for 2016, compared to previous years. All three score highly and seem pleased with their results. 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. Alkanes are the typical oils used in many nonpolar solvents and they do not mix with water. A monomer is a molecule that may bind chemically to other molecules to. Some polymers are made via condensation polymerisation. Advanced aas level chemistry us k12 grades 1112 preuniversity, gcse 91 sciences revision.
As a result, cracking produces smaller alkanes and alkenes. Part 1 is where students make ethene then link to make polythene using molymods. For example, butane is an alkane with four carbon atoms. The reason for this is that cracking produces a new family of. As 90698 describe aspects of organic chemistry collated. Choose your answers to the questions and click next to see the next set of questions. Dec 31, 2015 summary video on cracking for gcse chemistry.
The cracking products, such as ethene, propene, buta1,3diene and c 4 alkenes, are used to make many important chemicals. These monomers the starting materials are often alkenes the process chemical reaction that turns monomers into polymers. Cracking is used to convert long alkanes into shorter, more useful hydrocarbons. Gcse chemistry definitions when learning definitions i find it easier to move around and say them to yourself. Which of the following species can best serve as a radical initiator for radical polymerization. Addition polymerization chemical reaction britannica.
The monomer molecules may be all alike, or they may represent two, three, or more different compounds. The process chemical reaction that turns monomers into polymers. In liquid phase catalytic cracking, the reaction mixture is maintained at a temperature of about 500 o c and 20 atm pressure. Apparatus delivery tube and bung bunsen burner boiling tube containing mineral wool porous pot liquid paraffin clamp and stand. Steam cracking is an uncatalyzed, thermal cracking process used in the petrochemical industry to break down hydrocarbons. The process also results in the slow deposition of coke, a form of carbon, on the reactor walls. The reaction mechanism is a chain reaction that entails initiation, propagation, and termination. Its a process studied in gcse chemistry, so you need to understand it.
But you dont just use cracking to transform one product into another. Cracking is the name given to breaking up large hydrocarbon molecules into smaller and more useful bits. May 01, 2014 organic chemistry gcse complete scheme of work 2016 specification includes carboxylic acids, alcohols, condensation polymers, biological molecules. Chemsitry polymerisation flashcards in gcse chemistry. The simulation you will see displays this process graphically.
Best igcse organic chemistry notes complete breakdown. Polymerisation is the reaction of monomer molecules to form long chain polymer molecules. The process of converting a monomer or a mixture of monomers into a polymer. This process results in octane numbers ranging from 65 to 70. It is the remains of organisms that lived and died millions of years ago mainly plankton which was buried in mud. In vapor phase catalytic cracking, about 600 o c temperature and 10 atm pressure is used. The oxygen reacts with some of the ethene to give an organic peroxide. Chemistry revision notes on the topic cracking hydrocarbons.
As well as using a normal type of molecular formula to describe an organic molecule, they can be represented by drawing out their structure i. In this process, steam is added to the mixture of gaseous hydrocarbons ethene, butane, crude gasoline, or longchain hydrocarbons. Long chain hydrocarbons can be broken into smaller hydrocarbons, by heating with a. Percentage of pupils who achieved at least each grade. The chain grows only at the reactive end, the end with the unpaired electron. It allows ethene molecules to join together to form a single product, so it is an example of an addition reaction. Cracking and alkenes gcse chemistry single science revision. This page also contains the link to the notes and video for the revision of this topic. Cracking converts large alkane molecules into smaller, more useful, alkane and alkene molecules. C 3 h 8 the following formula satisfies the general formula of alkane, and consists of 3 carbon atoms. Which of the following species can best serve as an initiator for cationic polymerization. Its written by teachers especially to help year 10 and year 11 students revise. Making small molecules by breaking down large molecules.
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