C7 - Organic chemistry An overview of the information in C7 2.5 / 5 based on 4 ratings ? ChemistryOrganic and Green ChemistryGCSEOCR Created by: Chris RickettsCreated on: 25-04-11 13:21 Hydrocarbon alkanes Made up of only hydrogen and carbon atoms Formula for hydrocarbons is Cn H2n+2 e.g. methane = CH4, Ethane = C2H6, propane = C3H8, Butane = C4H10 Properties include: unreactive with water oily burn well in plenty of oxygen with the formula: Alkene + O2 --> CO2 +H2O e.g. C2H6 (g) + 3.5 O2 (g) --> 2 CO2 (g) + 3 H2O (l) Does not react with sodium 1 of 5 Alcohols Have the functional group -OH, giving alcohols their characteristics Formula for alcohols is Cn H2n+1 OH e.g. methanol = CH3OH, ethanol = C2H5OH Both can be used as fuels and to manufacture solvents Properties include: combust in oxygen because of the hydrocarbon chain with the formula: alcohol + O2 --> H2O + CO2 have stronger attractions between molecules so have higher boiling points than alkanes longer molecules are more oily reacts with sodium less violently than water 2 of 5 Carboxylic acids Have the functional group COOH with gives carboxylic acids their characteristics formula for carboxylic acids is Cn-1H2n-1COOH e.g methanoic acid = HCOOH, ethanoic acid = CH3COOH Properties include very unpleasant smells and tastes are weak acids can be neutralised by metals alkalis and carbonates e.g. Ethanoic acid + sodium --> sodium ethanoate + Hydrogen, Methanoic acid + sodium carbonate --> sodium methanoate + water + carbon dioxide Carboxylic acids are found in: vinegar - dilute ethanoic acid rancid butter sweaty socks/ feet - butanoic acid 3 of 5 Esters Carboxyilic acids and alcohols react in the presence of a strong acid catalyst, to form esters e.g. Methanol + ethanoic acid --(sulfuric acid)--> methyl ethanoate + water Esters are prepared by: mixing an alcohol and excess carboxylic acid and heating them in reflux (under a condenser) in the presence of concentrated sulphuric acid distilling this mixture by heating it and using a condenser as esters have lower boiling points than most other substances In a separating funnel, sodium carbonate is added, reacting with any remaining acid and extracting it to an aqueous phase, which is run off In a conical flask, a drying agent is added to remave and remaining water, which is later removed by filtration. Estersd have distinctive, sweet smells and are found in perfumes and food products as well as naturally occuring in fruits They are also found in solvents like adhesives and plasticisers because of their hydrocarbon chains 4 of 5 Fats 5 of 5
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