Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Hydrocarbons • • • • • • Systematic naming Alcohols. P,S,T. Diol, triol Alcohol properties (H-bonds) Oxidation – oxidising agents – routes Aldehydes / Ketones - isomers Carboxylic acids A Any acceptable structural formulae for propanal Silver mirror Water bath (flammable reactants) Primary alcohol Proteins • • • • • • Amino acids (essential) Peptide link, polypeptide enzymes Denaturing Lock and key Optimum settings C B One which the human body cannot synthesise itself. We need to get it through our diet. H Bonds? Redraw the amino acids with alanine shown on the left hand side and phenylalanine on the right hand side. Now condense them together (losing water) to show your answer Esters, Fats and oils • Esters – making (catalyst),naming, structures, uses, condensation, hydrolysis Ethanoic acid Concentrated sulphuric acid Add a wet paper towel to act as a condenser Esters, Fats and oils • Fats / oils - Animal, vegetable, marine • Fats/oils are esters (fats/oil also known as triglycerides) • Glycerol structure / Fatty acids (ratio) • Properties of fat (saturated) vs oil (unsaturated) • London dispersion forces to explain melt points D The process breaks some C=C double bonds decreasing the level of unsaturation. This “hardening” process results in an increase in melting and boiling point. Soaps, detergents, • • • • Soaps (salt of fatty acid) Structure How they work Hydrophobic, hydrophilic Mechanism of stain/dirt removal Roll-up mechanism The hydrophobic tails ‘burrow’ into the droplet of oil or grease. The hydrophilic heads are left to face the surrounding water. This results in the formation of a ball-like structure (a micelle). The non-polar substances, such as oil or grease, are held inside the ball and suspended in water, to be washed away. Soaps, detergents, • Soap scum • Detergents • Emulsion – small droplets of one liquid dispersed in another • Emulsifiers – Allow oil and water to mix OC SOAP: Carboxyl head O O S O O- DETERGENT: SULPHONATE (SO3-) head • The calcium salt of a sulphonate is soluble in water unlike the calcium salts of the carboxylate. • Hence no scum is formed Antioxidant • Oxygen reacts with edible oils giving them a rancid flavour • Antioxidants prevent this – they get oxidised in place of the oil (or other food) • Ion electron equation (the antioxidant LOSES electrons) Oxidation of food - video • Fats and oils can go rancid in two ways: Oxidative rancidity • The double bonds are cleaved (broken) by free radical mechanism Hydrolytic rancidity • The ester link is hydrolysed releasing the fatty acids (some are foul smelling) Antioxidant molecules are REDUCING AGENTS, they donate an electron to the oxidising agent The food is “protected” because the antioxidant is oxidised in place of the food. Ion-electron equations can be used to show how antioxidant molecules are oxidised. C6H8O6 C6H6O6 + 2H+ + Vitamin C DHA (ascorbic acid) (dehydroascorbic acid) 2e- Fragrances • Isoprene unit • ID the number of units used to make terpene • Terpenoid (oxidised terpenes) Essential Oils • Essential oils are the concentrated extracts of volatile, non-water-soluble aroma compounds from plants. • Terpenes are the key components in most essential oils. Absinthe – a cyclic terpenoid CH3 H3C This terpene has been oxidised to a terpenoid CH C H2C CH2 HC C CH CH3 Thujone (Absinthe) O Terpenes • Terpenes are unsaturated compounds formed by joining together isoprene units. One isoprene unit contains five carbon atoms Head Tail CH3 C CH2 CH = CH2 Isoprene (2-methylbuta-1,3-diene) Steam Distillation • Steam passes over the plant and extracts the essential oil. • The mixture evaporates and passes into the condenser. • The essential oil vapour is chilled and collected Skin care • UV – high energy form of light • Provides energy to break bonds (forms free radicals - causes sunburn) • Sun block prevents UV reaching the skin • Free radicals – Initiation – Propagation – Termination • Free radical scavengers • Initiation Cl2(g) Cl.(g) + .Cl(g) • Propagation H2 (g) + .Cl (g) H. (g) + Cl2 (g) H. (g) + HCl (g) HCl (g) + Cl. (g) • Termination H.(g) + .Cl(g) HCl(g) H.(g) + .H(g) H2(g) Cl.(g) + .Cl(g) Cl2(g) Free Radical Scavengers • Many cosmetic products contain free radical scavengers. • These are molecules which can react with free radicals to form stable molecules and prevent chain reactions. addition Redraw the butanal to look as similar as possible to the propanone in the original example. Use this as a guide to work out the product CH3-CH2 H CH3-CH2 H