School Science Lessons
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3.0.0: Breakdown, energy, fats, rate of reaction, solubility
Table of contents
3.95 Breakdown large molecules to small molecules
3.80 Energy from chemical reactions
3.90 Fats in food
3.12.0 Heat energy from chemical reactions
3.91 Rate of reaction
3.75 Reactions of salts with water

3.90 Fats in food
See: Fat (Commercial) Fats in food Antioxidants omega-3 fatty acids food additives Cholesterol, saturated fats and heart disease, alternative views Classification of fats Coconut oil in the diet
19.2.11 Composition of edible oils Fatty acids, ω-3 and ω-6 fatty acids Fats in animals and plants Free radicals and antioxidants Fish oils Heat fats Hydrogenation, cis-trans fatty acids
Linoleic acid
Linolenic acid Modified polyphenol technology in wines Margarine
Margarine (emulsion)
Oleic acid, C17H33COOH
Olive oil Rancidity Trans fats, Omega-fatty acids

3.95 Breakdown large molecules to small molecules
3.95 Breakdown starch to sugars
3.96 Breakdown ethanol to ethene (ethylene)

3.80 Energy from chemical reactions
3.84 Electrical energy from the displacement of copper by zinc
3.80 Exothermic reactions give out heat energy, make surroundings warmer
3.81 Endothermic reactions take in heat energy, make surroundings colder
3.12.0 Heat energy from chemical reactions
3.82 Heat of neutralization reactions, hydrochloric acid with sodium hydroxide
3.83 Heat of reaction, metals displace copper

3.91 Rate of reaction
3.7.2 Rate of reaction
3.94 Catalysts and rate of reaction
3.92 Concentration and rate of reaction, sodium thiosulfate with hydrochloric acid
3.7.1 Concentration, parts per million (ppm)
3.91 Size of particles and rate of reaction with balloons
3.75 Reactions of salts with water
Water and salts do not usually react but sometimes hydrolysis occurs and the solution becomes either acidic or alkaline.
Dissolve a small amount of the following salts in demineralized water and test each solution with red and with blue litmus paper:
sodium chloride, sodium carbonate, copper (II) sulfate, sodium acetate, iron chloride, copper (II) sulfate and iron chloride give acidic
Sodium carbonate and sodium acetate give alkaline solutions.
Sodium chloride solution is neither acidic nor alkaline.

3.80 Exothermic reactions, the reactants form products with rise in temperature
Be careful! The reactions may be vigorous.
If less energy is needed to break the bonds in a reaction than the energy released by making the bonds, the reaction is endothermic.
1. Put 1 cm of white anhydrous copper (II) sulfate powder in a test-tube.
Hold a thermometer with the bulb in the powder.
Add water drop by drop.
Record any change in the thermometer reading.
(Water with anhydrous compounds reactions.)
CuSO4 + 5H2O --> CuSO4.5H2O

2. Put 10 mL of 0.4 M copper (II) sulfate solution into a wide test-tube.
Support a thermometer with the bulb in the solution.
Add magnesium powder, or magnesium ribbon, a little at a time, until the blue colour disappears.
Record any change in the thermometer reading.
Magnesium is higher in the reactivity series than copper so it displaces copper from its sulfate.

3. To a little water in a wide test-tube, add concentrated sulfuric acid, drop by drop, down the side of the test-tube.
Stir gently with a thermometer after the addition of each drop.
Record any change in the thermometer reading.
(Concentrated acid with water reactions)

4. Citric acid with sodium hydrogen carbonate solution: 12.6.6
5. Thermite reaction: 12.1.5
6. Dilute hydrochloric acid with dilute sodium hydroxide solution.
(Neutralization reactions)
7. Burning substances and combustion of fuels.
8. Setting of cement and concrete
9. Corrosive oxidation of metals.

3.81 Endothermic reactions take in heat energy
See diagram 3.81: Temperature of potassium nitrate solution
An endothermic reaction drops in temperature as it absorbs heat energy.
If more energy is needed to break the bonds in a reaction than the energy released by making the bonds, the reaction is endothermic.
Endothermic dissolving processes of a solid in a solvent are associated with low solubility.
1. Put 10 mL of water in a test-tube.
Read the temperature of the water.
Dissolve 2 g of potassium nitrate in the water.
The temperature should fall through 90oC.
So while dissolving, the particles are absorbing heat energy.
This energy is taken from the surrounding water.
Repeat the experiment with potassium chloride.
Mg + CuSO4 --> MgSO4 + Cu displacement

2. Add citric acid to sodium hydrogen carbonate solution in styrofoam cup.
Stir the solution and note the temperature change.
When the reaction stops the temperature should return to room temperature.
H3C6H5O7 (aq) + 3NaHCO3 (s) --> 3CO2 (g) + 3H2O (l) + Na3C6H5O7 (aq)

3. Dissolve ammonium chloride in water.
4. Dissolve ammonium nitrate in water.
5. Dissolve potassium chloride in water.
6. Dissolve urea in water.
7. Pass dry ammonium chloride over barium hydroxide octahydrate crystals.
8. Add sodium carbonate to ethanoic acid.
9. Add thionyl chloride (SOCl2) to cobalt (II) sulfate heptahydrate.
(Prepare thionyl chloride, SOCl2:

3.82 Heat of neutralization reactions, hydrochloric acid with sodium hydroxide
1. Dissolve 40 g of sodium hydroxide pellets in water and make up to 500 mL, a 2M solution.
Prepare 500 mL of a 2M hydrochloric acid solution and leave to cool.
Note the temperature of the solutions when cool.
Quickly add the acid to the base and carefully stir with a thermometer.
Note the maximum temperature reached.
The increase of temperature should be 13oC.
The volume of water has been doubled by adding one solution to the other, so the final solution contains 1 mole of OH- (aq) ions that
reacted with 1 mole of H+ (aq) ions to form 1 mole of water molecules.
Assume that the specific heat of this weak solution is the same as the specific heat of water.

2. Put 25 mL of 2.0 M sodium hydroxide solution into a polystyrene cup and measure the temperature of the sodium hydroxide
Stand the polystyrene cup in a beaker.
Put 25 mL of 2.0 M hydrochloric acid in a measuring cylinder and measure the temperature of the acid.
The sodium hydroxide and the hydrochloric acid should have the same room temperature.
Pour the acid into the sodium hydroxide, stir the solution with the thermometer, and note the highest temperature of the mixture.
Record the temperature difference reached in the mixture.
After each temperature measurement rinse the thermometer and dry it with absorbent paper.
Repeat the experiment with 50 mL of 2.0 M sodium hydroxide and hydrochloric acid.
Repeat the experiment with 50 mL of 1.0 M sodium hydroxide and hydrochloric acid.
Compare the temperature differences reached in the 3 experiments.

3.83 Heat of reaction, metals displace copper
See diagram 3.2.83: Temperature rise of the reacting solution
1. Put 25 mL of 0.2 M copper (II) sulfate solution in a 100 mL plastic bottle fitted with a one-hole stopper and thermometer.
Replace the stopper, invert the bottle and shake it gently.
Record the temperature of this solution.
Turn the bottle the right way up, remove the stopper and add 0.5 g of zinc dust.
The quantity of zinc powder is in excess to ensure that all the copper (II) sulfate is used up in the reaction, so some zinc will remain
when the reaction stops.
Replace the stopper, invert the bottle, and shake gently.
Record the highest temperature reached.
Calculate the rise of temperature.
This rise of temperature in not affected by the volume of 0.2 M copper (II) sulfate used for the experiment.
For a 1 M solution, multiply the rise in temperature by 5 (5 × 0.2M = 1.0 M).
The reactants lost energy to the solution.
The temperature change is usually between 9oC and 10oC.
Zn (s) + Cu2+ (aq) ---> Zn2+ (aq) + Cu (s)

2. Repeat the experiment with 0.5 g of iron powder or iron filings.
This amount is again in excess so that all the copper (II) sulfate will be used up in the reaction.
The temperature change is usually between 6oC and 7oC.
The zinc metal became zinc ions and copper ions became copper metal because of transfer of electrons from zinc metal to the copper
To get electrical energy, these electrons must flow in an external conductor, e.g. a wire, from the zinc to the copper.
The potential or voltage will reflect the greater activity of zinc over copper.
The current flowing will depend on the extent and rate of the reaction.

3. Fix two lead foil strips in a beaker and add 200 mL of 1 mol per litre sulfuric acid.
Connect the lead electrodes to a power pack set at 2 V and switch it on for two minutes.
The lead strip connected to the positive terminal becomes covered with brown lead dioxide.
Disconnect the power pack and connect the lead strips to a torch battery.
The battery glows but the brown leads dioxide on the positive terminal does not disappear.
Repeat the experiment with increasing charging times.
The time the battery glows increases with charging time up to 30 seconds then hardly changes.
Repeat the experiment with different charging voltages.
Different charging voltage makes hardly any difference in the time the battery glows.
However, at high charging voltages hydrogen is produced at the negative electrode and oxygen at the positive electrode.
At the positive electrode: Pb (s) + 2H2O (l) --> PbO2 (s) + 4H+ (aq) + 4e-
At the negative electrode: 2H+ (aq) + 2e- --> H2 (g)
Also, lead reacts with the sulfuric acid to produce lead sulfate
At the positive electrode: PbSO4 (s) + 2H2O (l) --> PbO2 (s) + 4H+ (aq) + SO42- + 2e-
At the negative electrode: PbSO4 (s) + 2e- --> Pb (s) + SO42- (aq)
So sulfuric acid is produced during charging and is consumed during discharging.
As sulfuric acid has about twice the density of water, the density of the electrolyte shows the state of charge of the battery.

4. When the battery is fully charged, the specific gravity = 1.280, electrode A is lead and electrode, B is lead dioxide.
When the battery is discharging, electrode A changes from lead to lead sulfate, electrode, B changes from lead dioxide to lead sulfate,
and the concentration of sulfuric acid decreases.
When the battery is being charged, these processes are reversed.
The concentration of sulfuric acid suggests the state of charge of the battery so this concentration can be measured with a battery
Electrode A: Pb + SO42- --> PbSO4 + 2e-
Electrode B: PbO2 + 4H3O+ + SO42- + 2e- --> PbSO4 + 6H2O
In a motor car battery, the electrodes have a coat of lead (II) oxide (PbO) and lead powder (Pb).
In the electrolyte, electric current converts the PbO to Pb on the negative plate, and the PbO to lead (IV) oxide (lead peroxide)
PbO2 on the positive plate.
Discharging -->
PbO2 + 2H2SO4 + Pb < = > 2PbSO4 + 2H2O
<-- Charging
If you pass electricity through the battery after it is fully charged, "gassing" occurs, i.e. water is decomposed into hydrogen and
oxygen gas.
Never smoke or allow a naked flame near a charging battery.

3.84 Electrical energy from the displacement of copper by zinc
See diagram 3.84: Copper and zinc foil in a voltmeter, a simple cell
1. Put concentrated copper (II) sulfate solution in a beaker.
Connect copper foil to the positive terminal, red wire, of a voltmeter and a zinc foil to the negative terminal, black wire.
Simultaneously dip the two metals briefly into the copper sulfate solution.
Record the readings on the voltmeter.
The voltage falls to zero after a short time because black copper deposited on the zinc and caused the reaction to stop.
When copper deposits on the zinc electrode, it prevents more zinc from entering the solution.
This causes the voltage to fall to zero after a short time and the cell becomes "dead".

Separate the electrolytes to prevent the voltage fall by using 1. a Daniell Cell that has a porous pot, or 2. a salt bridge.
2. Pour concentrated copper (II) sulfate solution into a beaker.
Connect a copper rod to the positive terminal of a voltmeter and a zinc rod to the negative terminal.
Dip the two metals briefly into the copper (II) sulfate solution.
Zinc dissolves and hydrogen bubbles form on the surface of the copper.
The voltmeter reads 1.1 V, so electrons are moving from the zinc to the copper.

3.91 Size of particles and rate of reaction with balloons
See diagram 3.2.91: Size of particles and rate of reaction
1. Use a hammer to break natural marble chips into four sizes:
1.1 coarse powder, 1.2 half a rice grain, 1.3 rice grain, 1.4. marble chips.
Put 2 g of each size separately into four test-tubes.
Blow up four balloons several times to stretch them.
Put 5 mL of dilute hydrochloric acid into each of the four balloons.
Slip the mouths of the balloons over the tops of the test-tubes but do not let any acid enter the test-tubes.
Tip the acid from each balloon into the attached test-tube.
Note which balloon is the fastest and the slowest to expand because of the production of carbon dioxide.
The coarse powder produces carbon dioxide in the shortest time.

2. Repeat the experiment without balloons but with four conical flasks on a sensitive top balance.
Add 5 mL of dilute hydrochloric acid to 2 g of coarse powder and note the loss in weight every 30 seconds.
Then continue the experiment with the other sizes of marble chips.

3.92 Concentration and rate of reaction, sodium thiosulfate with dilute hydrochloric acid
See diagram 3.2.92: Black cross no longer visible
1. Dissolve 5 g sodium thiosulfate crystals in 500 mL water.
Add 5 mL hydrochloric acid to 50 mL the sodium thiosulfate solution.

2. Dissolve 20 g of sodium thiosulfate in 500 mL of water and put 50 mL of the solution in a container.
Place the container on a black cross marked on a sheet of paper.
Add 5 mL of dilute hydrochloric acid to the container and note the time.
Look down through the solution and note when the black cross is no longer visible.
Sulfur is produced during the reaction making the solution cloudy.
Repeat the experiment with 40 mL of sodium thiosulfate solution and 10 mL of water.
Add 5 mL of dilute hydrochloric acid.
The time when the black cross is no longer visible is greater.
Repeat the experiment with 30 mL of sodium thiosulfate solution and 20 mL of water.
The time when the black cross is no longer visible is still greater.
Repeat the experiment with 20 mL of sodium thiosulfate solution and 30 mL of water.
Use graph paper to plot the volume of the thiosulfate solution (concentration) against time taken for the reaction.
Na2S2O3 (aq) + 2HCl (aq) ---> H2O (l) + SO2 (g) + S (s) [The S (s) causes the solution to become cloudy.]
(S2O3)2- (aq) + 2 H+ (aq) --> H2O (l) + SO2 (g) + S (colloidal)

3.94 Catalysts and rate of reaction
See diagram 3.2.94: Catalysts and rate of reaction
1. Put a cube of sugar in a glass or aerated water, e.g. fizzy lemonade.
The drink fizzes more because the sugar cube provides more sites for the formation of carbon dioxide bubbles on the sharp corners
of the sugar crystals.
The sugar is said to act as a physical catalyst.

2. Fill a burette with water and invert it in a container of water to measure the volume of a gas in the burette by downward
displacement of water.
Use a flask or test-tube fitted with a one-hole stopper and bent delivery tube.
Add 2 mL of 20 volumes to 50 L of water in the flask.
Note the time then immediately add 1 g of manganese (IV) oxide to the flask, close the stopper and adjust the end of the delivery tube.
inside the burette.
Note the volume of hydrogen gas in the burette at intervals of 15 seconds.
Repeat the experiment with copper (II) oxide, nickel oxide and zinc oxide.
Use graph paper to plot the volume of oxygen gas produced every 15 seconds against the time of the reaction.
Manganese (IV) oxide is the best catalyst for this reaction.

3.95 Breakdown starch to sugars
| 9.130 Hydrolysis of starch by salivary amylase (ptyalin)
| 9.142.3 Tests for starch with Fehling's solution
| 16.10.1 Tests for hydrolysis of starch, iodine test, Fehling's solution
Salivary amylase enzyme breaks down starch into the reducing sugars (+) glucose and maltose.
Reducing sugars do not react with iodine solution and starch does not react with Fehling's solution.
The sugars reduce copper (II) in Fehling's solution to brick-red copper (I) oxide.

1. Prepare a clear solution of laundry starch by adding a mixture of 1g starch in 10 ml of water to 500 mL of boiling water, then leave
the solution to cool to room temperature.

2. Put 10 mL of dilute starch solution into a test-tube.
Add to this 1 mL of saliva and stir this into the starch solution.
Record the time of adding the saliva.
After 2 minutes use a dropper to put 2 drops of the solution on a white tile.
At 5 minute intervals, remove three drops with a dropper and put them on a clean white tile, taking care to keep them from running
into each other.
The dropper must be washed between each test.

3. To test for starch, add iodine solution and note the intensity of the blue black colour.
The decreasing intensity of the blue colour shows the decreasing amount of starch.

4. To test for increasing amounts of sugar, put three drops of the reaction mixture into a small test-tube.
Add Fehling's No. 1 and No. 2 solutions and heat this mixture almost to boiling point.
Note the intensity of the brick-red colour increasing with time.
Repeat the experiment every 2 minutes with clean droppers.
Note the decreasing intensity of the blue colour that shows that starch is being used up.
Keep doing the test until it shows that there is more sugar after boiling.

3.96 Breakdown ethanol to ethene (ethylene)
See diagram 3.2.96: Breakdown of ethanol
Push cotton wool soaked in methylated spirit to the bottom of a hard glass test-tube.
Pack small pieces of porous pot, unglazed porcelain, in the middle of the test-tube.
Fit a delivery tube to collect ethene gas over water in a receiving test-tube.
With the hard glass test-tube in a horizontal position, heat the porous pot strongly, then gently heat the cotton wool to produce ethanol
The ethanol vapour breaks down over the hot porous pot to produce ethene gas and water vapour.
Ethene is insoluble in water and collects in the receiving test-tube.
Collect three receiving test-tubes full of ethene then immediately disconnect the delivery tube when you stop heating to avoid a suck
back of water on the hot porous pot.
In test-tube 1, burn ethene with a lighted taper.
Shake test-tube 2 with drops of dilute potassium manganate (VII) solution and sodium carbonate solution.
The colour disappears.
Shake test-tube 3 with bromine water.
The colour disappears.
C2H5OH (l) ---> C2H4 (g) + H2O Fats in food
See diagram 19.2.1: Glycerol, triglyceride, cis and trans, oleic acid, stearic acid, linoleic acid
Fats, oils and some waxes are the naturally occurring esters of long, straight chain carboxylic acids.
These esters are the materials from which soaps are made.
At room temperature, fats are solid or semi-solid and oils are liquids.
alcohol + organic acid ---> ester + water glycerol + fatty acid ---> fats or oils + water
All fats form from glycerol, glycerine, propan-1, 2, 3-triol, CH2OHCHOHCH2OH.
The fatty acid part of the fat differs as follows:
1. in the length of the chain, which controls the molecular mass, and
2. the number and position of the double bonds, unsaturation.

The 3 main groups of fatty acids are as follows:
1. Saturated fatty acids, e.g. stearic acid,
2. Straight chain unsaturated fatty acids, e.g. oleic acid,
3. Polyunsaturated fatty acids, e.g. linoleic acid.

The normal saturated fatty acids have the general formula CH3(CH2)nCOOH, where n is usually an even number from 2 to 24,
e.g. stearic acid (n=16) lauric acid (n=10).
Milk contains short chain fatty acids, n < 10.

The building block for fatty acids is the acetate ion, CH3COO-.
The most important unsaturated fatty acids have 18 carbon atoms with one double bond in the middle of the chain, called
mono-unsaturated fatty acids.
Polyunsaturated fatty acids have more double bonds between the middle double bond and the carboxyl group, COOH.
Atoms can rotate about single bonds but not about double bonds, so two arrangements are possible called "cis" and "trans".
Most double bonds in natural fats and oils are cis, e.g. oleic acid in olive oil.
Fatty acids with the cis double bond do not pack together easily so have a low melting point of double bond containing material, i.e. oils.
Substances made up of shorter chains also melt at lower temperatures.
Chemists describe polyunsaturated fatty acids as having more than one cis-methylene interrupted double bond. Fats in animals and plants
1. Fats and oils are used to store, transport and utilize the fatty acids that an organism requires for its metabolic processes.
Energy storage in animals: fat 38 kj / g, carbohydrates 17 kj / g, protein 23 kj / g.
Fats store water and when metabolized in the body to produce energy, they also produce water, e.g. fatty hump of the camel.
Plants, fungi, yeasts and bacteria, can synthesize both fats and their component fatty acids.
Animals can synthesize most of their fatty acid needs, but they prefer to ingest plant foods and modify them to their own needs.
Only plants can synthesize linoleic and linolenic acids, but animals can increase the chain length and further increase unsaturation,
e.g. fish oils, that are rich in unsaturated acids.
Saturated fatty acids are predominantly present in fats that are solid at room temperature, e.g. milk, butter and animal fats.
Saturated fats may raise the level of "bad" cholesterol leading to hardening of the arteries, high blood pressure, heart disease and strokes.
Animals produce mainly saturated fats because their fats also have a structural support function and must not be too fluid.
Some animals can maintain a high temperature through internal heating, insulation and behaviour.
Unsaturated fatty acids may be mono-unsaturated or polyunsaturated.
Mono-unsaturated fatty acids, e.g. oleic acid, are found in most animal and plant fats and oils, especially olive oil.
Unsaturated fatty acids occur mainly in oils.
Most fats and oils contain a mixture of saturated and unsaturated fatty acids but in widely varying proportions.
An intake of fat in the diet is essential as some fatty acids are required for important functions in the body.
Fat soluble vitamins A, D, E and K must also be provided by food containing fat.
A fat free diet is not only difficult to prepare but is also very unpalatable.

2. The so-called "bad cholesterol" is the LDL (low density lipoprotein) cholesterol used to build body cells but excess can form plaque
on the walls of arteries to the heart and brain causing atherosclerosis.
The so-called "good cholesterol" is HDL (high density lipoprotein) cholesterol produced in the liver and intestines that removes excess
cholesterol from atherosclerosis plaques and my protect from heart attack.
Electrophoresis is used to separate the LDL fraction of total cholesterol to measure the HDL and LDL levels and determine the risk
factors for coronary heart disease.

3. Polyunsaturated fatty acids, e.g. linoleic acid, linolenic acid, are found mainly in vegetable oils.
Polyunsaturated fats are essential to animals as building blocks and for controlling the cholesterol content of the blood.
Plants produce mainly unsaturated oils that allow them to withstand extremes of temperature because their fats or oils are fluid at low
Polyunsaturated fats lower "bad" cholesterol but also lower "good" cholesterol.
Polyunsaturated fats are found in margarine, vegetable oils and seed oils.
Some research claims that polyunsaturated fats may be are oxidized into "free radicals" that contribute to the development of some
cancers and accelerate ageing.

4. Mono-unsaturated fats are the "good" fats and should make up most of the fats in a diet, up to about 30% of a diet.
Saturated fat in the diet can raise the level of blood cholesterol to increase the risk of heart disease from atherosclerosis, fatty plaques
on the walls of blood vessels.
Unsaturated fat can form free radicals by lipid peroxidation, leading to cancer and accelerated ageing.
So both saturated and unsaturated fat can have health hazards! Classification of fats
1. Saponification value from hydrolysis of a fats into component fatty acids, as their anions or soaps, and glycerol.
Saponification value = number of milligrams of potassium hydroxide to saponify one gram of fat (or oil).
It is a measure of the average chain length, molecular mass of the fatty acids.
2. Fat and saponification value:
Coconut oil 250-260, Butter 245-255, Lard (pig fat) 193-200, Peanut oil 185-195, Linseed oil, 189-196. 3.
Iodine value measures the number of double bonds in the fat.
Iodine reacts with the double bond.
Iodine value is the number of grams of iodine that react with 100 g of fat or oil.
Fats with low iodine values are saturated.
Fats with high iodine values are polyunsaturated.
Fat and iodine value: Coconut oil 8-10, Butter 26-45, Lard 46-66, Peanut oil 83-98, Linseed oil 170-204. 3.
3. Acid value measures how much glycerides in the fat or oil have been decomposed to free acid.
This is regulated by food standards codes.
4. Peroxide value measures the oxygen taken up by the oil to form peroxides and is a measure of the freshness of the oil.
This regulated by food standards codes.
5. Oxygen uptake.
If polyunsaturated fats are incubated at 60oC, they gain weight from oxygen uptake. Hydrogenation, cis-trans fatty acids
See: Glyceryl Tristearate (Commercial)
3[CH2O(CO)(CH2)7CH==CH(CH2)7CH3] + 3H2 --->3[CH2O(CO)(CH2)16CH]
glyceryl trioleate + hydrogen (nickel catalyst) + heat ---> glyceryl tristearate
Hydrogenation means to add hydrogen to a molecule.
Unsaturated fats can be saturated by adding hydrogen to the double bonds with a nickel catalyst.
Hydrogenation converts a substance with the properties of a liquid vegetable oil into a substance with the properties of a solid animal
fat, e.g. linoleic and oleic acids turn into stearic acid.
Margarine is made from pure vegetable oils but the manufacturing process may cause some hydrogenation of unsaturated fatty acids.
Processed oils such as shortenings may contain a high proportion of fats changed by hydrogenation.
In nature, most unsaturated fatty acids are cis fatty acids, i.e. the hydrogen atoms are on the same side of the double carbon bond.
In trans fatty acids the two hydrogen atoms are on opposite sides of the double bond.
Trans double bonds can occur in nature as the result of fermentation in grazing animals so people eat them in the form of meat and dairy
Trans double bonds are also formed during the hydrogenation of vegetable or fish oils, e.g. French fries (fried potato chips) donuts, and
other snack foods are high in trans fatty acids.
Manufacturers may hydrogenate polyunsaturated oils to help foods to stay fresh or to obtain a solid fat product, e.g. margarine.
Trans fatty acids, i.e. hydrogenated fats, tend to raise total blood cholesterol levels, and raise LDL bad cholesterol and lower HDL
good cholesterol.
In some countries, governments have required fast food companies to commit to reducing trans fats in their cooking and listing trans fat
content on labelling.
Some companies have claimed that consumers do not like the taste of products if all trans fats are eliminated.
However, apparently, if only a small proportion of trans fats are used, taste is not a problem.
In other countries, trans fats in cooking have been banned altogether by legislation. Rancidity
Oxygen in the air oxidizes unsaturated fats adjacent to the double bond to produce smaller easily evaporated volatile compounds with
a rancid smell.
Most of the fatty acids in butter are C16 -C18, but shorter chain fatty acids are also present.
The acid from rancid butter is 1, 3-butadiene: CH2=CH-CH=CH2, a butane with two double bonds, bivinyl butyric acid: C3H7COOH.
Cheeses made from milk with more short chain fatty acids have a stronger smell.
Margarine rarely becomes rancid because the longer chain fatty acids must first be broken before the short chain, rancid smelling
compounds form.
Purchased fats and oils have added antioxidants to prevent rancid compounds from forming.
The same short chain acids in rancid butter are present in human perspiration. Heat fats
Smoke point is the temperature at which a fat breaks down into visible gaseous products and thin wisps of bluish smoke begin to rise
from the surface.
Smoke point, smoking point, falls with the continued use for cooking because the oil or fat decomposes and the free fatty acids have a
lower smoke point.
So the higher the initial smoke point, the longer the fat is usable before it starts to smoke.
Smoke point of an oil or fat is an important piece of information for consumers and should be listed on food labels.
Flash point is the higher temperature when bursts of flame start.
Ignition temperature, is the higher temperature at which the entire surface of the frying medium becomes covered with flame.
P/S ratio is the ratio of polyunsaturated fatty acids to the saturated fatty acids present.
Although heating may not change the P/S ratio of polyunsaturated oils, it causes the formation of oxidized compounds, which tend to
destroy the vitamin E content and make oils unpalatable.
Changes in the peroxide value of oils after heating reveal how heating oxidizes oils.

Olive oil
Olive oil is composed mainly of triglycerides, composed of a mixture of three fatty acids, and small quantities of free fatty acids (FFA),
glycerol, phosphatides, pigments, flavour compounds, and sterols.
The major fatty acids in olive oil triglycerides are:
Oleic acid, monounsaturated omega-9 fatty acid, 55 to 83% of olive oil.
Linoleic acid, polyunsaturated omega-6 fatty acid, 3.5 to 21% of olive oil.
Palmitic acid, saturated fatty acid, 7.5 to 20% of olive oil.
Stearic acid, saturated fatty acid, 0.5 to 5% of olive oil.
Linolenic acid, alpha-linolenic acid, polyunsaturated omega-3 fatty acid, 0 to 1.5% of olive oil.
Olive oil contains more oleic acid and less linoleic and linolenic acids than other vegetable oils, so it is more monounsaturated than
polyunsaturated fatty acids.
So olive oil is more resistant to oxidation because if more double bonds in a fatty acid, it is more unstable and easily broken down by
heat and light.
Olive oil is the most stable cooking oil because it also contains a steroid stabilizer, so it needs no refining, preservatives or refrigeration.
Some people do not fry in olive oil because of the low smoke point, 165-190oC, but olive oils produce less toxic aldehydes than other
cooking oils and can be used safely for frying for up to 10 times.
Olive oil contains no preservatives, but keeps much longer than other edible oils, particularly if kept in an air-tight container and away
from heat and light.
However, olive oil kept in a refrigerator becomes thick and cloudy.
Trade names:
1. "Olive oil", is usually a refined or blended oil with acid content less than 3.3%.
2. "Virgin Olive oil" is a premium oil with excellent aroma and flavour, maximum acid content 1.5-2.0 %, for cooking and salad dressing
(3 parts olive oil, 1 part vinegar or lemon juice).
3. "ExtraVirgin Olive Oil", best quality edible oil, maximum acid content 1.0 %.

Approximate values
1. Safflower oil: smoke point: 246oC, P/S ratio: 6.0
3. Sunflower oil: smoke point: 229oC, P/S ratio: 4.7
3. Maize oil: smoke point: 229oC, P/S ratio: 3.1
4. Peanut oil: smoke point: 246oC, P/S ratio: 1.9
5. Soybean oil: smoke point: 256oC, P/S ratio: 3.7
6. Olive oil: smoke point: 204oC, P/S ratio: 0.5 Antioxidants, vitamin E
See diagram Antioxidants, BHT, BHA, TBHQ, Propyl gallate, vitamin E
Antioxidants reduce damage by reactive oxygen.
Antioxidants inhibits oxidation or reaction with oxygen, are soluble in oil and cheap to produce.
Antioxidants are preservatives for fatty products and oils that are themselves oxidized instead of the added substance to prevent the
occurrence of oxidation, i.e. rancidity.
E319, tertiary butylhydroquinone (TBHQ), a phenol, C10H14O2
E310-E312 are antioxidant esters allowed in edible oils, margarine, table spreads, and salad oils.
Antioxidants are related to the "natural" antioxidant, vitamin E, α-tocopherol and have similar properties.
Antioxidants in green tea may be at a concentration of 21 mg of total polyphenols per 100 mL. Modified polyphenol technology in wines
Red wine is said to contain polyphenol and anthrocyanidin antioxidants and the antioxidant reservatol in the skin.
Queensland biochemist-turned-winemaker claims to have created a wine that is beneficial to drinkers' health, by: Rob Kidd,
he Courier-Mail, January 20, 2013 12:00 AM
A Queensland biochemist-turned-winemaker claims to have created what drinkers had only dreamed of wine that is beneficial to your
Greg Jardine, founder of Mt Nebo-based company Dr Red Nutraceuticals, filed a patent for Modified Polyphenol Technology in
Wines late last year and said the creation would "finally give wine a really medicinal edge".
The process involved ageing red wine for a certain period, which enhanced the number of antioxidants within it, made them fat-soluble,
rather than water-soluble, and easier to absorb into the bloodstream.
Some studies have shown antioxidants are effective at fighting many different diseases.
Mr Jardine said he had been working on the process for 10 years but had only recently discovered a way to retain the taste while
enhancing antioxidants.
"Wine has got massive amounts of antioxidants but they are quite tannic so if you put more in people would not drink it because of the
taste, " he told The Sunday Mail.
What we discovered was if we allowed them to age and stop it at the right point of time the tannic taste goes and we make it taste good".
Biomedical Sciences Professor Lindsay Brown, from the University of Southern Queensland, found the non-alcoholic dried crystal
used to make the wine successfully treated rats with arthritis.
"The results were astonishing.
Right from the outset of the 14-day trial, this wine was effective . . .
and by day four, it achieved a near-perfect recovery" he said.
Ren Gray-Smith claims to have felt the benefits of a new wine that creator, biochemist and wine maker, Greg Jardine claims is good for
your health.
Mr Jardine said the wine could help treat a "range of ageing conditions" from chronic fatigue and gout to stiff joints after a visit to the gym.
Ren Gray-Smith, 51, of Red Hill, in Brisbane's inner west, was suffering from fatigue and irregular sleep patterns when she switched
her regular glass of red to Mr Jardine's creation.
"I was feeling very tired, had bad sleep patterns and (the wine) just helped to get me back on the right track, " she said.
Stressing the wine is "not medicine", Mr Jardine said it should be consumed in moderation as it has the same alcoholic content as
regular wine.
"We gave people one glass, not 50 glasses but it had 50 times more antioxidants in the glass, " he said.
"For years the word has been a glass a day is good for you but we are finally proving it.
We believe this is a game-changer for the food industry in Australia."
'But before another toast, more research was needed to prove any beneficial effects, said clinical pharmacologist Creina Stockley.
"If they can show it has a demonstrative effect in humans it's worth pursuing, " she said. Cholesterol
See: Models, biochemistry, Cholesterol, (Commercial)
See diagram Steroids
1. Cholesterol, C27H46O, modified steroid, lipid molecule, about 25% biological cell membrane, controls membrane permeability,
synthesized in small intestine and liver, --> steroid hormones and bile acids, from animal fats, cheese, egg yolk
High cholesterol levels in the blood indicate the potential for atherosclerosis and coronary heart disease.
Cholesterol is a fat-like molecule, an alcohol, base of all steroids, e.g. sex hormones, bile acids, vitamin D and cortisone.
Cholesterol is not a fat, but a steroidal alcohol.
It has 27 carbon atoms, so it is not a terpene.
It is essential for the blood and cell membranes and is found in all the cells of the body.
It is produced in the liver and also comes from foods of animal origin.

2. Cholesterol in the blood becomes coated with a phospholipid protein envelope called lipoprotein in a high density form (HDL) and
a low density form (LDL).
In countries where people eat large amounts of meat and dairy products, their diets are high in cholesterol and saturated fats and so the
mortality rate from heart disease is high.
In countries where diets are low in cholesterol and rich in the polyunsaturated fats found in vegetable oils and fish, the death rate from
coronary disease is lower.
Vegetable oils contain phytosterols instead of cholesterol.
Isolation of ergosterol used to be used as evidence proving the addition of vegetable oil to animal products.
Atherosclerosis occurs when excess LDL cholesterol circulates in the blood, accumulates in the inner walls of the arteries to the heart
and brain, and reacts with other substances to form a plaque that can clog those arteries.
A blood clot can form to block a narrowed artery and can cause a heart attack or stroke.
So the levels of HDL cholesterol and LDL cholesterol in the blood are measured to evaluate the risk of heart attack.
An LDL cholesterol level < 130 mg / dL is optimal for most people.
However, an LDL cholesterol level > 130 mg / dL reflects an increased risk of heart disease, so LDL cholesterol is called "bad"
Up to one fourth of blood cholesterol is carried by high density lipoprotein (HDL).
It is called "good" cholesterol because it may protect against heart attack by carrying cholesterol away from the arteries and back to
the liver, to be excreted from the body.
Most people can raise their HDL (good cholesterol) levels by exercising, not smoking and staying at a healthy weight.

3. Triglyceride levels < 150 mg / dL are normal.
Triglyceride levels from 150-199 are borderline high.
Levels that are borderline high or high (200 mg / dL to 499 mg / dL) may need medical treatment.
Triglyceride levels of 500 mg / dL or above are very high.
Doctors need to treat high triglycerides in people who also have high LDL cholesterol levels.
People with high triglycerides often have a high total cholesterol, a high LDL cholesterol and a low HDL cholesterol level.
People with heart disease, diabetes or who are obese are likely to have high triglycerides level, high LDL cholesterol level and a low
HDL cholesterol level.

4. LPG cholesterol is a genetic variation of plasma LDL that may cause fatty deposits in arteries.
Lpa is a genetic variation of plasma LDL.
A high level of Lpa is an important risk factor for developing fatty deposits in arteries prematurely.
The way an increased Lpa contributes to disease is not understood.
The lesions in artery walls contain substances that may interact with Lpa leading to the build up of fatty deposits. Cholesterol
Cholesterol, saturated fats and heart disease, alternative views
Some people do not believe in any connection between cholesterol and heart disease:
1. "It's amazing how long the myths concerning the connection between saturated fats and heart disease and cholesterol can survive
despite evidence to the contrary when considering the statistics and despite the serious side effects of the drugs.
Even Ancel Keys (the initial experimenter) has said that there is no connection between cholesterol and heart disease.
Coconuts and butter and pasture fed beef are good for you! Just read Uffe Ravnskov's "The Cholesterol Myths."

2. "I cannot think of any topic of debate that has more lies, half-truths, serious omissions, bad science and general intellectual dishonesty
than saturated fat and cholesterol.
This I believe is down to vested interests.
Both the production of margarine and statins are highly profitable.
The only scientific study showing saturated fat in negative light was the Seven Countries done by Ancell Keys where he in fact had data
from 22 countries but cherry picked data to show a pre-determined outcome.
This is classic bad science No other scientific study concurs with his finding since from the 1930's in the USA as the pre-capita
consumption of traditional animal fats decreased and the consumption of vegetable oil and margarine went up, heart disease took
off and increased rapidly, so if anything, saturated fat protects against heart disease.
As it has been pointed out on the radio program the consumption of coconuts and coconut oil is high in the Philippines and Pacific
This being the case if saturated fat causes heart disease then heart disease should be highly prevalent in these places but this does not
appear to be the case.
What does cause heart disease is trans fat found in margarine and hardened vegetable oil.
It is a by product of partial hydrogenation.
There have been numerous studies showing trans fat to be the cause of heart disease." Trans fats, Omega-fatty acids
Trans fats are trans isomer (E-isomer) fatty acids .
Fatty acids, together with glycerine, are the building blocks of all fats and oils.
Trans fatty acids are unsaturated but, unlike the "good" unsaturated fatty acids found in fish and vegetable oils, behave similarly to
saturated fats in the body and have similar health issues.
Trans fats can be found naturally in meat and milk from certain animals and as a product of fats and oils altered by industrial processes,
such as hydrogenation.
Hydrogenation is widely used to solidify liquid vegetable oils to make products such as margarine and shortenings and involves adding
hydrogen to the oils.
Trans fats are not formed through deep frying food in vegetable oils.
However, manufactured fats such as margarine spreads, fats used in deep frying and fats used in pastry dough, are likely to
contain some trans fats because they improve the firmness of the product and the products are less likely to be damaged by oxidation,
or heat.
Trans fats make cooking oils more stable.
Some fats are good for us and can help reduce the "bad" type of cholesterol that causes a lot of health problems.
These good fats include polyunsaturated, monounsaturated fats, omega-3 fatty acids, omega-6 fatty acids or omega-9 fatty acids.
Both trans fats and saturated fats increases the level of "bad" cholesterol, with trans fats also decreasing the level of "good" cholesterol.
This can cause a number of serious health problems.
Studies have shown that Australians consume relatively low amounts of trans fatty acids compared with people in other countries.
However, the amount of saturated fats consumed by Australians is of greater concern so the amount of total fat and the amount of
saturated fat must be declared on all food labels.
The amount of trans fat in food must be declared on the label if a nutrition claim is made about cholesterol, polyunsaturated,
monounsaturated fats, omega-3 fatty acids, omega-6 fatty acids or omega-9 fatty acids.

Omega-3 fatty acids
Unsaturated fatty acids
The omega-3 fatty acids group have the first double bond between the third and fourth carbon atoms counting from the right,
i.e. from the methyl group.
Omega-3 fatty acids, C60H92O6, N-3 polyunsaturated fatty acid, first unsaturated bond in the third position from the omega carbon,
(the carbon atom of the methyl group at the end of the hydrocarbon chain).
e.g. Linolenic acid, α-linolenic acid, C18H30O2, CH3(CH2)CH=CH(CH2)CH=CH(CH2)CH=CH(CH2)7COOH
Omega-3 fatty acids may reduce serum triglycerides, prevent insulin resistance, improve lipid profile, prolong bleeding times, reduce
platelet counts, and decrease platelet adhesiveness.
e.g. Alpha-linoleic acid, C18H30O2, in seed oils, e.g. rapeseed.
e.g. Eicosapenaenoic acid, C20H30O2, in cod liver oil.
Omega-6 fatty acids, C38H64O4, N-3 polyunsaturated fatty acid, first unsaturated bond in the sixth position from the omega carbon.
e.g. Linolenic acid, C18H32O2, in grapeseed oil.
Omega-9 fatty acids, avocado oil is 70% omega-9 fatty acid.
e.g. Oleic acid, C18H34O2 in olive oil and macadamia oil.
e.g. Erucic acid, C22H42O2, in mustard oil and rapeseed, but not canola oil. Fatty acids, ω-3 and ω-6 fatty acids
The ω-3 fatty acids is a family of polyunsaturated fatty acids.
The parent ω-3-α-linolenic acid (ALA) is obtained from the diet and is polyunsaturated with 8 carbon atoms and 3 double bonds.
The long chain ω-3 fatty acids eicosapentaenoic acid, EPA, and docosahexaenoic acid, DHA, can be synthesized from dietary ALA,
but in seems that EPA and DHA should be obtained from the diet containing oily fish and fish oil as well as fortified bread and fruit juice.
ALA, EPA and DHA are important role for structural membrane lipids, in nerve tissue and the retina beside a wide range of functions
in cells and tissues. Free radicals and antioxidants
Free radicals
A free radical is a molecule carrying an impaired electron.
Free radicals are extremely reactive.
As free radicals take an electron from the other molecules, they convert these molecules into free radicals or breakdown or alter their
chemical structure.
Free radicals can damage proteins, sugars, fatty acids and nucleic acids that combine and accumulate as "age pigment".
The main free radicals are superoxide radical (SOR), hydroxyl radical (OHR), hydroperoxyl radical (HPR), alkoxyl radical (AR),
peroxyl radical (PR), and nitric oxide radical (NOR).
Other molecules that are not free radicals, but act much like them, are singlet oxygen, hydrogen peroxide (H2O2) and hypochlorous
acid (HOCl).
For example, the hydroxyl radical, -OH, is the most destructive free radical, can seize a hydrogen atom, H, from a protein to form water
and a damaged protein which is now a free radical.
Free radical damage to LDL cholesterol causes atherosclerosis.

The free radicals and non-free radical mimics are called "oxidants" or "reactive oxygen species" (ROS).
Free radicals live for only a few seconds because of their extreme reactivity.
Free radical damage includes ageing, cancer, heart / artery disease, hypertension, disease, ageing immune deficiency, cataracts,
diabetes, inflammatory disease, and just "ageing".
Free radicals and oxidants are produced by normal physiological processes and by enzymes that detoxify pollutants.
Monosaturated fats, cholesterol, and saturated fats are subject to free radicals but polyunsaturated fatty acids are most susceptible.

Antioxidants are molecules that can react with free radicals to accept or donate an electron to eliminate unpaired electrons and so
neutralize the action of the free radicals.
In humans, the first line of antioxidant defence are the antioxidant enzymes, e.g. glutathione peroxidase (GPX), and tripeptide glutathione
(GSH) that help destroy SOR, H2O2 and lipid peroxides.
Also, vitamins C and E, and the mineral selenium have a major antioxidant role, besides various drugs.
Vitamin C may be the most important nutrient antioxidant.
Vitamin E is the chief fat-soluble antioxidant, and occurs in all membranes.
The α-lipoic acid (ALA) is a quasi-vitamin anti-oxidant.
It can be made by the body, but also absorbed from diet or supplements. Margarine
See: Experiment
See 16.3.9: Diacetyl, butanedione
An example of a legal definition of table margarine is that it is a mixture of edible fats, oils and water, prepared in the form of a water
in oil emulsion containing < 16% water, < 4% salt and > 8.5 mg of vitamin A and > 55 g of vitamin D per kilogram.
The P:S ratio is the ratio of polyunsaturated fat to saturated fat.
A "heart-healthy" margarine should have a P:S ratio > 2:1.
The term polyunsaturated is permitted where the proportion of cis-methylene interrupted polyunsaturated fatty acids in the margarine
is > 49%, the proportion of saturated fatty acids < 20% of the total fatty acids, and the P/S ratio > 2: 1.
The total cholesterol content must appear on the packet as mg / 100 g.
The remaining 40% of the fatty acids can be mono-unsaturated, e.g. oleic acid.
A softer margarine that requires constant refrigeration has a P/S ratio 3:1.
Table margarine may contain antioxidants, flavouring, e.g. flavour of butter from 3-hydroxy-2-butanone and diacetyl (2, 3-butanedione,
dimethylglyoxal, C4H6O2), and vegetable colouring, e.g. usually carotene, a source of vitamin A, and which gives the colour to butter.
Previously, margarine contained coconut oil, but producers changed to soybean oil because of concern about the high content of
saturated fats in coconut oil.
However, new margarine-like products contain coconut oil, along with non-genetically modified and naturally cholesterol-free
vegetable oils, but not palm oil, e.g. "Nuttelex".

Margarine label
Information from the label on a 250 g packet of an Australian "Original, Cholesterol free spread" margarine.
Ingredient list: Vegetable oils, water salt, skim milk powder and whey powder, emulsifiers (soybean lecithin, 471), food acid (citric)
colour (β-carotene), vitamin A and D, flavour.
Keep refrigerated.
Contains 70% fats and oils.
No artificial colours. Virtually free of trans fatty acids.
Contains soy and milk as indicated in bold type.
Table 4.3.0 Margarine label
Nutrient Quantity per 5 g serve Quantity per 100 g
Energy 130 kj 2 620 kj
Protein < 1 g < 1 g
Fat, total 3.5 g 70 g
Saturated fatty acids 0.9 g 17 g
Trans fatty acids 0.03 g 0.63 g
Polyunsaturated fatty acids 0.9 g 17.0 g
ω-3 fatty acids 0.25 g 5 g
ALA 0.25 g 5 g
Mono-unsaturated fatty acids 1.7 g 34 g
Cholesterol nil nil
Carbohydrate < 1 g < 1 g
Sugars < 1 g < 1 g
Sodium 49 mg 790 mg
Vitamin A 50 g, ** 7% RDI) 1 000 g
Vitamin D 0.5 g (** 5% RDI) 10 g
Potassium 1 mg 14 mg
** RDI, Recommended dietary intake (Australia / New Zealand)

Observe the label of a packet of margarine bought in your local store.
Note list the list of ingredients and compare it to the list above. Coconut oil in the diet
Proponents of including coconut oil in the diet claim that In the United States, the interests of the US domestic fats and oils
industry and soybean growers were successful at driving down usage of coconut oil by pointing to the high concentration of saturated
fats in coconut oil.
During concern over increased rates of heart disease the edible oil industry's response at that time was to claim that it was only the
saturated fat in the hydrogenated oils that was causing the problem.
Not being domestically grown in the US, coconut oil and palm oil industries were not able to defend themselves.
However, the proponents for coconut oil say it is rich in short and medium chain fatty acids.
Desiccated coconut is about 69% coconut fat and coconut milk is about 24% fat.
About 50% of coconut fat is lauric acid, which has antibacterial, antiviral and antiprotozoal functions in food.
Also, another one medium chain fatty acid, capric acid, has been added to the list of coconut's antimicrobial components.
It is claimed that natural coconut fat in the diet leads to a normalization of body lipids, protects against alcohol damage to the liver, and
improves the immune system's anti-inflammatory response and that the medium chain fatty acids and monoglycerides found primarily in
coconut oil have tremendous healing power. Fish oils
Fish oils, ω-3, containing eicosapentaenic acid, EPA and docosahexaenoic acid, DHA, are taken as supplements to lower total serum
triglycerides and maintain healthy levels of cholesterol.

19.2.11 Composition of edible oils
Table 1.1.1
Type of Oil % Monounsaturated fat % Polyunsaturated fat % Saturated fat
Canola oil 58.9 29.6 7.1
17.0 Coconut oil
5.8 1.8 86.5
Corn oil 12.7 58.7 24.2
Flaxseed oil 22 74 4
Grape seed oil 16.1 69.9 8.1
Olive oil 77 8.4 13.5
Palm oil 37 9.3 49.3
Palm kernel oil 11.4 1.6 81.5
Peanut oil 46.2 32 16.9
Safflower oil 12.6 73.4 9.6
Sesame oil 39.7 41.7 14.2
Soybean oil 23.3 57.9 14.4