Saturated fat

Unsaturated fat

Fat molecule that has no carbon –carbon double bonds

Fat molecule that has at least ONE carbon –carbon double bonds

Oil

Fat

Liquid at room temperature and found in plants

Solid at room temperature and found in animals

Glycerol

Fatty acids

An alcohol that has 3 hydroxyl group in 1 molecule

Carboxylic acid that has a long chain carbon, about 10 to 20 carbon atoms and has only one carboxyl group

Examples of oils

Examples of fats

Coconut oil, corn oil

Meat, butter, cheese

Examples of saturated fats

Examples of unsaturated fats

Soybeans, peanuts, sunflower seeds, maize

Meat, butter, cheese

cholesterol

Hydrogenation Addition of hydrogens to the double bonds between 2 carbon atoms

White, fatty substance that make blood vessels become hard and narrow

a) State 2 similarities between fats and oils?

•Both are esters •Both occur naturally in living tissues of organisms

Oils Fats a)sources Plants and

animalsAnimals

a)Physical state

liquid solid

a)Melting point

Lower than 20 oC

Higher than 20 o C

b) Fill in the table below to list differences between oils and fats

Unsaturated fats ( C=C)

Saturated fats(C-C)

a)Proportion of molecules between saturated and unsaturated fats

More unsaturated molecules than saturated molecules

More saturated molecules than unsaturated molecules

c) Fill in the table below to list differences between saturated and unsaturated fats

Unsaturated fats ( C=C)

Saturated fats(C-C

b) Physical state at room temp

Mostly liquids

Mostly solids

c) Fill in the table below to list differences •between saturated and unsaturated fats

Unsaturated fats ( C=C)

Saturated fats(C-C)

c) Melting point

Lower melting point

Higher melting point

c) Fill in the table below to list differences •between saturated and unsaturated fats

Unsaturated fats ( C=C)

Saturated fats(C-C)

d) sources Plants and vegetables

Animals

c) Fill in the table below to list differences •between saturated and unsaturated fats

d) Why do unsaturated fats turn bad or spoil easily?

They contain carbon-carbon double bond that can easily reacts in the air.

e) Explain how unsaturated fats can be changed to saturated fats?

•Through catalytic hydrogenationWhere carbon-carbon double bond absorbs one mole hydrogen•The process is carried out by bubbling hydrogen gas through hot liquid oil in the presence of fine particles of nickel catalyst at temp of 200 o C and pressure 4 atm

+ +Carboxylic

acidsAlcohol Fats or

oilwater

3 molecules Fatty acid

1 molecule

Glycerol or 1,2,3-propanetriol

Has a very long chain carbon, (about 10-20 atoms)

Examples, palmitic acids, stearic acids, linoleic acids

FORMATION OF FATS OR OILS Three molecules of fatty acids combine

with one molecule of glycerol to form a fat molecule and water

a) From diagram above, what is glycerol?Draw its molecular formula

• Glycerol is an alcohol with three hydroxyl group in one molecule of glycerol

b) From diagram above, what is the difference between a fat molecule and a fatty acid molecule?

•A fat molecule is formed when long-chained carboxylic acid reacts with alcohol with three OH-groups (glycerol)•A fatty acid molecule is carboxylic acid molecule that has a long chain carbon atom ( about 10- 20 atoms)

c) Hexanoic acid and pentanol react together to form a product. Name the product formed and state its homologous series

Name of product: pentyl hexanoate

Homologous series : ester

•Can hexanoic acid and pentanol react together to form Fat or Oil? Explain your answer

No, because hexanoic acid is a short chain carboxylic acid with carbon atoms only 6 atoms and pentanol is not a glycerol

•Can decanoic acid and glycerol react together to form Fat or Oil? Explain your answer

Yes, because decanoic acid is a long chain carboxylic acid with carbon atom is 10 and reacts with glycerol

a) List examples of natural polymers and their monomers

•Complete the structural formula of natural rubber in the diagram below

•Or draw the structural formula of natural rubber in a simpler form

*** draw structure of its monomer!2-METHYLBUT-1,3-DIENE

b) State the properties of natural rubber

•White ……SOLID……… at room temperature•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 or rubber bearings to help absorb vibration•Making of gloves, tubes and hoses

•Latex is a …………COLLOID…………•It consists of ……RUBBER PARTICLES particles dispersed in ……WATER…•Each rubber particle is made-up many long-chain ………RUBBER………..molecules enclosed by a ………PROTEIN..-like membrane which is ……NEGATIVELY-charged

Process 1

The repulsion between the ……NEGATIVELY …..charged particles prevent the ……RUBBER particles from coming close to each OTHER THEREFORE LATEX COULD NOT COAGULATE

•When an ACID is added to latex, OR when latex is exposed to AIR , the BACTERIA ..from the air enters the latex and produce LACTIC acid that form HYDROGEN …ions. This HYDROGEN ….ions neutralize the NEGATIVE charges on the protein membrane.

Process 2

•The rubber PARTICLES can now come close together. This enable them to COLLIDE .with one another resulting in the BREAKAGE of the protein membranes.

Process 3

The rubber molecules combine with one another and entangle and thus causing the latex to coagulate  Draw diagram .

Process 4

iv) Describe how to prevent the coagulation of latexBy adding AMMONIA ….solution, that contains …HYDROXIDE ……….ions which …NEUTRALIZE ………. the acid produced by the bacteria . Therefore rubber particles remain …NEGATIVELY…… charged and the coagulation is PREVENTED

VULCANISED RUBBER a) What is meant by vulcanization of rubber?

ADDITION OF SULPHUR TO RUBBER AT 140 OC AND HIGH PRESSURE IN THE PRESENCE OF ZINC OXIDE AS THE CATALYST

b) In industry, how does the vulcanization of rubber is carried out? By heating latex with SULPHUR or a solution of sulphur monochloride in methylbenzene as solvent

c) Describe how sulphur atoms change the properties of rubber•In vulcanization , sulphur ….atoms form cross-link …between rubber molecules •These cross – LINK prevent rubber MOLECULES from sliding too much when STRETCHED•The rubber molecules return to their ORIGINAL ….. position after being stretched.

d) Draw cross-linkage of sulphur

e) Compare and contrast the properties of vulcanized and unvulcanised rubber•SimilaritiesBoth are ELASTICBoth are HEAT AND ELECTRICAL INSULATORS

Vulcanised Differences Unvulcanised rubber

More elastic Elasticity LESS elastic

Harder Hardness SOFTER More tensile strength

Tensile strength LESS tensile strength

•Differences

Vulcanised Differences Unvulcanised rubber

More resistance to heat

Resistance to heat

LESS resistance to heat

LESS SOLUBLE Effect of organic solvents

MORE SOLUBLE

•Differences

f) State one advantage of natural rubber over synthetic rubber

Only natural rubber can take the tremendous STRESS, STRENGH AND HEAT ………produced during landing and taking off of an aero plane