Production of Materials Section 1 Essay example

Submitted By matead
Words: 1939
Pages: 8

1. Fossil fuels provide both energy and raw materials such as ethylene, for the production of other substances

Construct word and balanced formulae equations of chemical reactions as they are encountered
Gather and present information from first-hand or secondary sources to write equations to represent all chemical reactions encountered in the HSC course
Acid reactions: * Ethylene/ethene=
C2H4

Ethylene/ethene=
C2H4

acid + base salt + water * acid + metal salt + hydrogen gas * acid + carbonate carbon dioxide gas + salt + water
Complete Combustion: * hydrocarbon + oxygen water + carbon dioxide * Displacement reaction: * Y + X(anion) X + Y(anion) where y>x *
Identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum * Ethene, commonly known as ethylene, is produced from the raw material, crude oil * Petroleum is a mixture of hydrocarbons * When crude oil is fractionally distilled, the petroleum gas section and gasoline (petrol) section are used in the production of plastics * The larger molecules can be broken up into smaller and more useful molecules by cracking, which is breaking the covalent bonds within larger molecules * One of these simple molecules is the petrochemical ethylene * Cracking is the process of breaking large hydrocarbon molecules into smaller length, using heat () * There are two types of cracking: thermal cracking and catalytic cracking * Thermal cracking: * Conditions: * High temperatures 800°C - 950°C * Hydrocarbon + steam * Process: 1. Initiation reaction – produces a radical
C10H22 2C5H11 ( C2H4 + C8H18 * The hydrogen atoms are removed from the hydrocarbon onto the catalyst’s surface and the positive hydrocarbon ion that forms undergoes further reaction leading to the formation of the final products * Using thermal cracking you get more ethylene so it is used more * Where energy is not available readily they use catalytic cracking * Catalytic cracking requires a lower temperature and is only one process * Ethylene can also be produced from the cracking of ethane (C2H6) * The ethane can be extracted from liquefied natural gas (LNG), which is in vast supply in the oil and gas fields of the Cooper Basin, in the central Australian desert * It is cracked at 850°C to form ethylene and hydrogen * The mixture of products, once formed, is rapidly cooled to prevent reaction reversal * Steam is generated for this process using the wast heat * If the products stay at high temperatures for too long they decompose to form carbon * C2H6 (g) C2H4 (g) + H2 (g) = +138kJ/mol * The reaction is endothermic, therefore higher yields of ethylene are produced at higher temperatures

Identify that ethylene, because of the high reactivity of its double bond, is readily transformed into many useful products * Alkenes are more reactive molecules due to the high electron density of the double bond * Electronegative elements, such as chlorine, bromine, and oxygen, are attracted to the double bond and electrons are transferred as they react * Alkenes are an unsaturated hydrocarbon, as the carbons are not each bonded with four separate molecules (unsaturated hydrocarbons have double and/or triple bonds) * Alkanes, also known as paraffins, are saturated hydrocarbons and they are relatively unreactive, to make them react UV light is used to produce free radicals * The double bond in ethylene allows it to react quickly and easily with other molecules, thus making it a useful starting point for producing many compounds, including solvents, pharmaceuticals, explosives, plastic, insecticides and many industrial chemicals * The most characteristic reaction with ethylene is the addition reaction where one of the bonds in the double bond breaks open and an atom is ‘added to’ or…