cholesterol White, fatty substance that make blood vessels become hard and narrowHydrogenation Addition of hydrogens to the double bonds between 2 carbon atoms
a) State 2 similaritiesbetween fats and oils?•Both are esters•Both occur naturally inliving tissues oforganisms
b) Fill in the table below to listdifferences between oils and fats Oils Fats a)sources Plants and Animals animals • Physical liquid solid state a)Melting Lower than Higher point 20 oC than 20 o C
c) Fill in the table below to list differencesbetween saturated and unsaturated fats Unsaturated Saturated fats fats ( C=C) (C-C) a)Proportion of More More saturated molecules unsaturated molecules than between molecules than unsaturated saturated and saturated molecules unsaturated molecules fats
c) Fill in the table below to list differences•between saturated and unsaturated fats Unsaturated Saturated fats fats ( C=C) (C-C b) Physical Mostly Mostly solids state at liquids room temp
c) Fill in the table below to list differences•between saturated and unsaturated fats Unsaturated Saturated fats fats ( C=C) (C-C) c) Melting Lower Higher melting point melting point point
c) Fill in the table below to list differences•between saturated and unsaturated fats Unsaturated Saturated fats ( C=C) fats d) sources Plants and (C-C) Animals vegetables
d) Why do unsaturatedfats turn bad or spoileasily?They contain carbon-carbondouble bond that can easilyreacts in the air.
e) Explain how unsaturated fats can be changed to saturated fats?•Through catalytic hydrogenationWhere carbon-carbon double bondabsorbs one mole hydrogen•The process is carried out bybubbling hydrogen gas through hotliquid oil in the presence of fineparticles of nickel catalyst at temp of200 o C and pressure 4 atm
Answer the following questions •FATS Oils and fats are esters Carboxylic + Alcohol Fats or + water acids oil Glycerol or 1,2,3- Fatty acid propanetriol Has a very long chain carbon, (about 10-20 atoms)Examples, palmitic acids, stearicacids, linoleic acids
a) From diagram above, what isglycerol?Draw its molecular formula• Glycerol is an alcohol with three hydroxyl group in one molecule of glycerol
b) From diagram above, what is thedifference between a fat molecule and afatty acid molecule?•A fat molecule is formed when long-chained carboxylic acid reacts withalcohol with three OH-groups (glycerol)•A fatty acid molecule is carboxylic acidmolecule that has a long chain carbonatom ( about 10- 20 atoms)
c) Hexanoic acid and pentanol reacttogether to form a product. Name theproduct formed and state itshomologous series Name of product: pentyl hexanoate Homologous series : ester
•Can hexanoic acid and pentanol reacttogether to form Fat or Oil? Explain youranswer No, because hexanoic acid is a short chain carboxylic acid with carbon atoms only 6 atoms and pentanol is not a glycerol
•Can decanoic acidand glycerol reacttogether to form Fat orOil? Explain your answer Yes, because decanoicacid is a long chaincarboxylic acid with carbonatom is 10 and reacts withglycerol
a) List examples of natural polymersand their monomers
•Complete the structural formula ofnatural rubber in the diagram below
•Or draw the structural formula ofnatural rubber in a simpler form
*** draw structure of its monomer!2-METHYLBUT-1,3-DIENE
b) State the properties of naturalrubber•White ……SOLID……… at roomtemperature•Elasticity that ………DECREASE…… overtime•Soft•Sensitive to …………HEAT..
•State 3 uses of natural rubber•In the making of tyres, footwear,rubber threads, rubber foam,conveyor belts and bitumen roads•Buildings built on rubber blocks orrubber bearings to help absorbvibration•Making of gloves, tubes and hoses
•Latex is a …………COLLOID…………•It consists of ……RUBBER PARTICLESparticles dispersed in ……WATER…•Each rubber particle is made-up many long-chain ………RUBBER………..moleculesenclosed by a ………PROTEIN..-like membranewhich is ……NEGATIVELY-charged
Process 1The repulsion between the ……NEGATIVELY …..charged particlesprevent the ……RUBBER particlesfrom coming close to each OTHERTHEREFORE LATEX COULD NOTCOAGULATE
Process 2•When an ACID is added to latex, ORwhen latex is exposed to AIR , theBACTERIA ..from the air enters thelatex and produce LACTIC acid thatform HYDROGEN …ions. ThisHYDROGEN ….ions neutralize theNEGATIVE charges on the proteinmembrane.
Process 3•The rubber PARTICLES can nowcome close together. This enablethem to COLLIDE .with one anotherresulting in the BREAKAGE of theprotein membranes.
Process 4•a) the collision between the rubberparticles cause the membrane to break•B) the rubber molecules inside themembranes are now set freeDraw diagram .
Process 5•The rubber molecules COMBINE ……with one each other and clumptogether . The latex is now coagulated
iv) Describe how to prevent thecoagulation of latexBy adding AMMONIA ….solution, thatcontains …HYDROXIDE ……….ionswhich …NEUTRALIZE ………. the acidproduced by the bacteria . Thereforerubber particles remain …NEGATIVELY…… charged and thecoagulation is PREVENTED
VULCANISED RUBBERa) What is meant by vulcanizationof rubber? ADDITION OF SULPHUR TORUBBER AT 140 OC AND HIGHPRESSURE IN THE PRESENCEOF ZINC OXIDE AS THECATALYST
b) In industry, how does thevulcanization of rubber is carriedout?By heating latex with SULPHURor a solution of sulphurmonochloride in methylbenzeneas solvent
c) Describe how sulphur atoms changethe properties of rubber•In vulcanization , sulphur ….atomsform cross-link …between rubbermolecules•These cross – LINK prevent rubberMOLECULES from sliding too muchwhen STRETCHED•The rubber molecules return to theirORIGINAL ….. position after beingstretched.