organic chem

alkanes

saturated hydrocarbons, molecular formula C_nH_2n+2. completely combusts to form water and carbon dioxide, incompletely to form water and carbon monoxide.

shorter chains have lower melting and boiling points, and burn more easily with a cleaner flame.

alkenes

unsaturated hydrocarbons, functional group C=C, molecular formula C_nH_2n, containing a C=C bond. burns similarly to alkanes but more likely to undergo incomplete combustion.

can be tested for with bromine water which goes colourless on exposure.

can undergo addition polymerisation by losing its C=C bond. can react with hydrogen to form an alkene, water to form an alcohol, and a halogen to form a halogenoalkane

alcohols

homologous series functional group -OH. used as a fuel, a solvent and in alcoholic drinks. can be formed through reacting water with alkenes or fermentation with yeast (best at around 25-35^oC, with an air lock to vent out CO₂ without letting in O₂ and with sugar dissolved in water). reacts with sodium to form sodium ethoxide and hydrogen. can be oxidised to form carboxylic acids.

carboxylic acids

homologous series group -COOH. reacts with alcohol to form esters, and are weak acids. they dissolve in water to create an acidic solution, and react with carbonates to form a salt, water and carbon dioxide.

esters

formed from alcohols and carboxylic acids, group -COO-. names [alcohol]yl [acid]oate, and water is produced in the reaction. can be used as solvents, smell like fruit.

undergoes condensation polymerisation to form polyesters, using condensations polymers. this reaction can be represented as n HO-■-OH + n HOOC-♦-COOH → (-■-OOC-♦-COO-)n + 2n H2O, or n HO-■-COOH → (-■-OOC-♦-COO-)_n + n H₂O

biological polymers

DNA, made up of nucleotides, code for proteins

proteins, made up of amino acids, functions include catalysing reactions (enzymes)

starch, made up of sugar, stores sugar

cellulose, made up of sugar, provides stability to plant walls

amino acids

two functional groups, -NH₂ and -COOH/carboxylic acid group. reacts with condensation polymerisation to form polypeptides and proteins.