chemistry c3 WJEC note cards on Alkanes and alkenes, Enzymes, Ethanol+ alcohol and ethanoic acid for WJEC 3.0 / 5 based on 1 rating ? ChemistryAcids, bases and saltsGCSEWJEC Created by: IwanCreated on: 04-05-09 20:58 carbon compounds Alkanes Alkanes are saterated hydrocarbons. Each carbon atom is bonded to 4 other atoms general formula for any alkane = CnH2n+n Alkanes with the same formula but different structures are called isomers Alkenes all their names end in -ene they all contain a C=C double bond General formula= CnH2n Alkenes are extreamly reactive because the double bond can break open to allow other atoms to add on When an alkene is added to bromine water it turns colourless the double bond splits open and the bromine adds on, this is called an addition reaction the product is saturated 1 of 4 Enzymes Enzymes Enzymes are biological catalysts Each enzyme has an optimum temperature and and optimum pH at which it works best at above the optimum temperature the activity begins to fall because the ebzyme is denatured 2 of 4 Ethanol and alcohols Ethanol is made from sugars by fermentation enzymes in yeast change the sugar to ethanol and carbon-dioxide glucose = ethanol + carbondioxide C6H12O6 = 2C2H5OH + 2CO2 ethanol can be obtained from the reaction mixture by distillation or fractional distillation Ethanol is used in alcholic drinks as a solvent and as a fuel Ethanol produces about 70% as much energy as petrol but it requires a large amount of sunlight and lots of land Importance of ethanol small amounts of ethanol are thought to help against heart disease excessive alcohol intake may lead to liver damage or alcohol dependency increased cost to the NHS due to alcohol related incidents drink driving impact on families taxes on alcoholic drinks raise money for public spending 3 of 4 Ethanol and Ethanoic acid Ethanol when exposed to the air undergoes oxydation caused by microbes the microbes change the ethanol into ethanoic acid ethanoic caid is a member of the carboxylic acid family Ethanoic caid reacts with sodium carbonate to give off carbon dioxide gas. fizzing is seen this reaction can be used as a test for carboxylic acid 4 of 4
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