unit 2 carbon compounds menu to work through a topic click on the title. fuels nomenclature and...

Unit 2

Carbon compounds

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• To work through a topic click on the title.

• Fuels• Nomenclature and structural formula• Reactions of carbon compounds• Plastics and synthetic fibres• Natural products• Click here to End.

Fuels

• A fuel is a chemical which burns, releasing energy.

• Combustion is another word for burning, the reaction of a substance with oxygen, in which energy is given out.

Hydrocarbons

• The chemical compounds which are found in oil and natural gas are mainly hydrocarbons.

• A hydrocarbon is a compound which contains hydrogen and carbon only.

• Hydrocarbons burn in a plentiful supply of air to produce carbon dioxide and water.

• The test for carbon dioxide is that it turns lime water milky.

Burning candle Lime water(turns cloudy)

Anhydrouscoppersulphate (turns blue)

To pump

Incomplete Combustion

• When fuels burn in a limited supply of air then incomplete combustion takes place and the poisonous gas, carbon monoxide (CO) is produced.

• Increasing the amount of air used to burn fuel improves efficiency and decreases pollution.

Other products of combustion

• Fossil fuels contain sulphur which produces sulphur dioxide when the fuel is burned.

• The oil industry tries to remove this sulphur from the fuels before selling them.

Nitrogen does not react well because of its strong bonds.

Air

+ -

HighVoltage sparkIf there is a high

temperature the nitrogen and oxygen will combine to make nitrogen oxides.

The experiment opposite shows how a high voltage spark, like one provided by the spark plug or lightning will do the same.

Nitrogen does not react well because of its strong bonds.

If there is a high temperature the nitrogen and oxygen will combine to make nitrogen oxides.

The experiment opposite shows how a high voltage spark, like one provided by the spark plug or lightning will do the same.

Air

+ -

HighVoltage spark

Browngas

Atmospheric Pollution

• The sulphur and nitrogen oxides produced can dissolve in water, making acid rain.

• Unburnt hydrocarbons escaping from car exhausts can help cause the destruction of the ozone layer.

Reducing Pollution

• Air pollution caused by burning hydrocarbons can be reduced by: using a special exhaust system – a catalytic converter, in which metal catalysts (platinum or rhodium) will convert pollutants into harmless gases.altering the fuel to air ratio.

Pollution

• Soot particles produced by the incomplete combustion of diesel are harmful.

Oil

• Crude oil is a mixture of chemical compounds (mainly hydrocarbons) which can be to split it into fractions.

• Oil can be separated into fractions by the process of fractional distillation.

Oil

• A fraction is a group of chemical compounds, all of which boil within the same temperature range.

Fractional Distillation of Oil

Heatedoil fromfurnace

gases

petrol (gasoline)

naphtha

paraffin (kerosine)

residue

diesel

(petrol)

(gaseous fuel)

(chemicals)

(aircraft fuel)

(fuel for lorries etc.)

(wax, tar)

Oil Fractions

Name Carbon atoms per molecule

Uses

Gases 1 to 4 Fuel

Petrol 4 to 9 Fuel for cars

Naphtha 8 to 14 Chemicals

Paraffin 10 to 16 Aircraft fuel

Diesel 15 to 20 Lorry fuel

Residue More than 20 Lubricating oil, tar, wax etc.

• Viscosity is a measure of the thickness of a liquid.

• Flammability is a measure of easily the liquid catches fire.

• As the boiling point of a fraction increases then:

• it will not evaporate as easily. • it will be less flammable• it will be more viscous

(thicker).

• Moving through the fractions from gases to the residue

• The molecules present in the fraction are longer and heavier

• They will find it more difficult to become a gas i.e. they will be less easy to evaporate.

• Moving up the fractions from gases to the residue

• Since combustion involves the reaction of gas molecules with oxygen flammability will decrease.

• Increased molecular lengths mean that molecules become more "tangled up", so the liquid will become thicker (more viscous).

Fuels

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Nomenclature &Structural formula

Nomenclature

• Nomenclature means the way chemical compounds are given names.

• These names are produced by a special system.

Naming hydrocarbons

• All hydrocarbons belong to “families” called homologous series.

• A homologous series is a set of compounds with the same general formula and similar chemical properties.

Homologous Series

General formula

Name

alkanes CnH2n+2 ….ane

alkenes CnH2n ….ene

cycloalkanes

CnH2n cyclo….ane

• The other part of the name tells us how many carbon atoms are present.

Number of C atoms

name Number of C atoms

name

1 meth- 5 pent-

2 eth- 6 hex-

3 prop- 7 hept-

4 but- 8 oct-

• This method works well for straight-chain hydrocarbons like hexane.

H H H H H H

H C C C C C C H

H H H H H H

• We have to add rules to help deal with branched chains.

H H H H CH3 H

H C C C C C C H

H H CH3 H CH3 H

• First draw out the full structure.

H H H H CH3 H

H C C C C C C H

H H CH3 H CH3 H

• Number the atoms in the longest continuous carbon chain.

• Start at the end nearest most groups. H H H H CH3 H

H C C C C C C H

H H CH3 H CH3 H

6 5 4 3 2 1

• This now gives us the basic name – in this case hexane.

H H H H CH3 H

H C C C C C C H

H H CH3 H CH3 H

6 5 4 3 2 1

• You must now identify any side chains.

• -CH3 is methyl

• -CH2CH3 is ethyl

• Now identify and count the number and type of side chain.

• di - shows 2• tri – shows 3• tetra – shows 4• Label the carbon atom(s) they

join

• This now gives us the full name:

• 2,2,4 trimethylhexane. H H H H CH3 H

H C C C C C C H

H H CH3 H CH3 H

6 5 4 3 2 1

• Naming alkenes works in the same way, except we start numbering at the end nearer the double bond.

H H H H CH3 H

H C C C C C C H

H C2H5 CH3 H

• Number the atoms in the longest carbon chain.

H H H H CH3 H

H C C C C C C H

H C2H5 CH3 H

1 2 3 4 5 6

• This now gives us the basic name – in this case hex-2-ene.

H H H H CH3 H

H C C C C C C H

H C2H5 CH3 H

1 2 3 4 5 6

• Identifying the side chains gives us the full name:

• 5,5 dimethy 4 ethyl hex-2-ene.

H H H H CH3 H

H C C C C C C H

H C2H5 CH3 H

1 2 3 4 5 6

• We can use the same principles with cyclic hydrocarbons.

H H

CH H C CH H C C H H H CH3

• 1 methyl cyclopentane H H

CH H C CH H C C H H H CH3

1

23

45

Isomers

• Isomers are compounds with the same molecular formula but different structural formulae

• For example C4H10

H C C C C H

H H H H

H H H Hbutane

H C C C H

H H H

H C H

H

H H

2 methyl propane

Alkanols

• The alkanols form another homologous series.

• We can recognise the alkanols because they contain an OH group.

• We can name the alkanols using the principles we have used before.

H H CH3 H H

H C C C C C H

H H H OH H

• 3 methyl pentan-2-ol

H H CH3 H H

H C C C C C H

H H H OH H

12345

Alkanoic acids

• The alkanoic acids form another homologous series.

• We can recognise the alkanoic acids because they contain a COOH group.

C OH

O

• We can name the alkanoic acids using the principles we have used before.

H H CH3 H H

H C C C C C

H H H H H

C OH

O

• 4 methyl hexanoic acid• We don’t need to number the

acid group because it must be on the first carbon. H H CH3 H H

H C C C C C

H H H H H

12345C OH

O

6

Esters

• An ester can be identified the ‘-oate’ ending to its name.

• The ester group is:

C O

O

Esters

• An ester can be named given the names of the parent alkanol and alkanoic acid.

• The name also tells us the alkanoic acid and alkanol that are made when the ester is broken down.

CH3 CH2 C OH

O

The acid and alkanol combine

HO CH3


CH3 CH2 C OH

O

HO CH3


Water is formed.

CH3 CH2 C

O

O CH3

H2O

Naming esters

Acid name Alkanol name

Ester name

ethanoic acid methanol methyl ethanoate

propanoic acid

ethanol ethyl propanoate

butanoic acid propanol propyl butanoate

methanoic acid

butanol butyl methanoate

• A typical ester is shown below.

H H O H H

H C C C O C

H H H H

C H

• We can identify the part that came from the alkanoic acid – propanoic acid.

H H O H H

H C C C O C

H H H H

C H

• We can identify the part that came from the alkanol - ethanol

H H O H H

H C C C O C

H H H H

C H

• This gives us the name ethyl propanoate

H H O H H

H C C C O C

H H H H

C H

Nomenclature and Structural Formulae

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Reactions of Carbon

Compounds

Saturated Hydrocarbons

• Alkanes and cycloalkanes are saturated hydrocarbons.

• Saturated hydrocarbons contain only carbon to carbon single covalent bonds.

Unsaturated Hydrocarbons

• The alkenes are unsaturated hydrocarbons.

• Unsaturated hydrocarbons contain at least one carbon to carbon double covalent bond.

• It is possible to distinguish an unsaturated hydrocarbon from a saturated hydrocarbon using bromine solution (bromine water).

• Take some bromine solution (brown) in test tube.

• Add a few drops of an unsaturated hydrocarbon.

• Unsaturated hydrocarbons decolourise bromine water.

colourless

Addition Reactions

• Addition reactions take place when atoms, or groups of atoms, add across a carbon to carbon double bond.

H H H H

C C + * * C C

* *

• When bromine adds to an alkene we have an addition reaction.

• C4H8 + Br2 C4H8 Br2

H H H H

C C + Br Br C C

Br Br

• The addition reaction between hydrogen and an alkene gives the equivalent alkane.

• propene + hydrogen propane

• C3H6 + H2 C3H8 H H H H

C C + H H C C

H H

• The addition reaction between water and an alkene gives the equivalent alkanol.

• propene + water propanol

• C3H6 + H2O C3H7OH

H H H H

C C + H2O C C

H OH

Cracking Hydrocarbons

• Fractional distillation of crude oil yields more long-chain hydrocarbons than are needed by industry.

• Cracking is an industrial method for producing a mixture of smaller, more useful molecules, some of which are unsaturated.

catalystmineral woolsoaked in oil

heat

gas

Cracking

• The cracking process can be carried out in different ways.

• Thermal cracking is where heat is used to split large molecules into smaller ones.

• Catalytic cracking is where a catalyst is used to split large molecules into smaller ones.

Catalytic Cracking

• A catalyst allows the reaction to take place at a lower temperature.

• Cracking can be carried out in the laboratory using an aluminium oxide or silicate catalyst.

• Some unsaturated hydrocarbons are produced because there are not enough hydrogen atoms to give completely saturated products.

Alcohol

• Alcohol (ethanol) is a drug.

• If we take too much alcohol it can have many harmful effects on our bodies and brains.

• Ethanol, for alcoholic drinks, can be made by fermentation of glucose derived from any fruit or vegetable.

• The type of alcoholic drink varies with the plant from which the glucose comes.

Fermentation

• During fermentation glucose is broken down to form ethanol; carbon dioxide is also produced.

• Fermentation is brought about by enzymes present in yeast.

• There is a limit to the amount of ethanol which can be produced by fermentation.

Distillation

• Distillation is a method of increasing the ethanol concentration of fermentation products in the manufacture of ‘spirit’ drinks.

• Water and alcohols can be partially separated by distillation because they boil at different temperatures.

Ethanol

• To meet market demand ethanol is made by means other than fermentation.

• Industrial ethanol is manufactured by the catalytic hydration of ethene. H H H

H

H C C H + H2O H C C H H OH

• Ethanol can be converted to ethene by dehydration.

H H H H

H C C OH C C + H2O

H H H H

• Ethanol, mixed with petrol, can be used as a fuel for cars.

• The ethanol is obtained from sugar cane, a renewable source of energy.

Condensation Reactions

• In a condensation reaction, the molecules join together by the reaction of the functional groups to make water.

H HO

H2O

Esters

• Esters are formed by the condensation reaction between a carboxylic acid and an alcohol.

• They can be recognised by the ester link:

C O

O

• The ester link is formed by the reaction of a hydroxyl group of an alkanol with a carboxyl group of a carboxylic acid.

H H

HO C C H

H H

• The ester link is formed by the reaction of a hydroxyl group of an alkanol with a carboxyl group of a carboxylic acid.

H H O

H C C C O H

H H

H H O

H C C C O H

H HCarboxylic acid

H H

HO C C H

H HAlkanol

H H O

H C C C O H

H H

H H

HO C C H

H H

H H O

H C C C O H

H H

H H

HO C C H

H H

Water is formed from hydrogen of one molecule and hydroxide from the other.

H H O

H C C C O

H H

H H

C C H

H HH2O


H H O

H C C C O

H H

H H

C C H

H HH2O


The remains of the molecules join together

Hydrolysis Reactions

• In a hydrolysis reaction, a molecule is split up by adding the elements of water.

H HO

H2O

• The carboxylic acid and the alcohol from which the ester are made can be obtained by hydrolysis.

CH3CH2COOCH3 CH3CH2COOH

+ H2O + CH3OH

• The formation and hydrolysis of an ester is a reversible reaction.

Acid + alkanol Ester + water

hydrolysis

condensation

Reactions of Carbon Compounds

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Plastics and Synthetic

Fibres

Plastics and Synthetic Fibres

• Most plastics and synthetic (i.e. man-made) fibres are made from materials which come from oil.

• Plastics are selected for various uses, according to their properties e.g. lightness, durability, electrical and thermal insulation.

• For some purposes synthetic materials are more suitable than natural materials.

• Plastics are selected for various uses, according to their properties e.g. lightness, durability, electrical and thermal insulation.

• There are many examples of plastics which we use in our everyday lives

• Polythene• Polystyrene• Perspex• PVC• Nylon• Bakelite• Formica• Silicones• Kevlar• Poly(ethenol).

Examples of Plastics and Synthetic Fibres

• Recently developed plastics are • Kevlar, which is very strong• Poly(ethenol), which readily

dissolves in water• Synthetic fibres, like polyesters

are• Terylene• Nylon.

Biodegradable

• Biodegradable means "able to rot away". Most plastics are not biodegradable and so cause environmental problems of disposal.

• A plastic called biopol has been developed which is biodegradable.

Burning plastics

• Certain plastics burn or smoulder to give poisonous fumes.

• The poisonous fumes that are released depend on the elements present in the plastic.

• All plastics can release carbon monoxide.

• P.V.C. can release hydrogen chloride

• Polyurethane releases hydrogen cyanide.

Thermoplastic or Thermosetting?

• A thermoplastic plastic is one which can be melted or reshaped (examples polythene, polystyrene, P.V.C.)

• A thermosetting plastic is one which cannot be melted and reshaped (examples bakelite in electrical fittings, formica in worktops)

Polymerisation

• A monomer is a small molecule which is able to join together with other, similar, small molecules.

• A polymer is the large molecule produced.

• This process is called polymerisation.• Plastics and fibres (natural and

synthetic) are examples of polymers. The making of plastics and synthetic fibres are examples of polymerisation.

Addition Polymerisation

• Many polymers are made from the small unsaturated molecules, produced by the cracking of oil.

• They add to each other by opening up their carbon to carbon double bonds.

• This process is called addition polymerisation.

H H

C C

H HThe ethene is attacked by an initiator (I*) which opens up the double bond

I*

The ethene is attacked by an initiator (I*) which opens up the double bond

I

H H

C C*

H H

Another ethene adds on.

H H

C C

H H


Another ethene adds on.

I

H H

C C

H H

H H

C C*

H H

Then another

H H

C C

H H


Another ethene adds on.Then another

I

H H

C C

H H

H H

C C

H H

H H

C C*

H H

….

Naming polymers

• The name of the polymer is derived from its monomer.

MONOMER POLYMER ***ene poly(***ene)ethene poly(ethene)propene poly(propene)styrene poly(styrene)chloroethene poly(chloroethene)tetrafluoroethene

poly(tetrafluoroethene)

Repeat Units

• You can look at the structure of an addition polymer and work out its repeat unit and the monomer from which it was formed.

• The repeat unit of an addition polymer is always only two carbon atoms long.

-CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -

Repeat Unit CH2 -CH2

-CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -CH2 -

-CH2 -CHCl -CH2 -CHCl -CH2 -CHCl -CH2 -CHCl

-

Repeat Unit CH2 -CHCl

-CH2 -CHCl -CH2 -CHCl -CH2 -CHCl -CH2 -CHCl

-

Condensation Polymers

• Condensation reactions involve eliminating water when two molecules join.

• Condensation polymers are made from monomers with two functional groups per molecule.

• Normally there are two different monomers which alternate in the structure e.g.

H H

and

HO OH

• The molecules join together, eliminating water as they do so.

• Hydrogen comes from one molecule.

• Hydroxide comes from the other molecule.

• The molecules join where these groups have come off.

• This repeats many times, joining together many of the monomers

H HHO OH

H OH

H2O

H H

H H

H2O H2O

HO OH

H

H2O H2O H2O

OHH H

H

H2O H2O H2O H2O

HHO OH

H OH

H2O H2O H2O H2O H2O

Repeat Units

• You can look at the structure of a condensation polymer and work out its repeat unit and the monomers from which it was formed.

-C-(CH2)4-C-N-(CH2)6-N -C-(CH2)4-C-N-(CH2)6-N-

O O H H O O H H

-C-(CH2)4-C-N-(CH2)6-N-

O O H H

-C-(CH2)4-C-N-(CH2)6-N -C-(CH2)4-C-N-(CH2)6-N-

O O H H O O H H

HO-C-(CH2)4-C-OH

O O

H-N-(CH2)6-N-H

H H

Polymer

Repeat Unit

Monomers

and

Polymer

Repeat Unit

Monomers

and

-O-C-C6H4-C-O-CH2-CH2 -O-C-C6H4-C-O-CH2-CH2-

O O 0 O

HO-CH2-CH2 -OH

-O-C-C6H4-C-O-CH2-CH2 -O-C-C6H4-C-O-CH2-CH2-

O O 0 O

H-O-C-C6H4-C-O-H

O O

-O-C-C6H4-C-O-CH2-CH2-

O O

Condensation Polymers

• Typical condensation polymers are polyesters and polyamides.

• Terylene is the brand name for a typical polyester.

• Nylon is a typical polyamide.

Polyesters

• As the name suggests polyesters are polymers which use the ester link.

• The two monomers which are used are a diacid and a diol.

The diacid will have a typical structure:

The diol will have a typical structure:

HO OH

They combine like this:

C-O-H

O

H-O-C

O

C-O-H

O

H-O-C

O



HO OH


C-O-H

O

H-O-C

O

C-O-H

O

H-O-C

O

HO OH



HO OH


C-O-H

O

H-O-C

O

C-O

O

H-O-C

O

OH C-O-H

O

H-O-C

O



HO OH


C-O-H

O

H-O-C

O

C-O

O

H-O-C

O

O C-O-H

O

-C

O

HO OH



HO OH


C-O

O

H-O-C

O

O C-O

O

-C

O

OH

C-O-H

O

H-O-C

O

Amines

• Amines are a homologous series containing the amine group:

N H

H

The amide link

• The amide link is formed when an acid and amine join together.

N H

H

HO C

O

The amide link


N

H

C O

H2O

The amide link


N

H

C O

The amide link

Polyamides

• A polyamide is made from a diamine and a diacid:

H N

H

N H

Hdiamine

C-O-H

O

H-O-C

O

diacid


H N

H

N H

H

C-O-H

O

H-O-C

O

H N

H

N H

H

H N

H

N

H

C-O-H

O

C

O

H2O

C-O-H

O

H-O-C

O

H N

H

N

H

C

O

C

O

N

H

N H

H

H2O H2O

H N

H

N

H

C

O

C

O

N

H

N

H

C-O-H

O

C

O

H2O H2O H2O

Plastics and Synthetic Fibres

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Natural Products

Carbohydrates

• Carbohydrates are important foods, produced by plants.

• Carbohydrates act as an important source of energy for animals.

• Carbohydrates burn, releasing energy and producing carbon dioxide and water.

• Carbohydrates contain the elements carbon, hydrogen and oxygen.

• There are two hydrogen atoms for each oxygen atom in carbohydrates e.g. C6H12O6 and C12H22O11

Sugars and Starch

• Carbohydrates can be divided into sugars and starches.

Sugars

• Sugars are sweet, dissolves well in water and let a beam of light pass through their solutions.

• Sugars are small molecules.

• Examples of sugars include glucose, fructose, maltose and sucrose (table sugar).

• Monosaccharides have formula C6H12O6.

• Disaccharides have formula C12H22O11.

Starch

• Starch is not sweet, does not dissolve in water and does not let a beam of light pass through its solution.

• Starch is a condensation polymer, made of large molecules.

Testing Carbohydrates

• Benedict's solution (or Fehling's solution) gives a positive test (an orange colour) with glucose, fructose, maltose and other sugars but NOT sucrose.

• Iodine will turn blue/black in the presence of starch.

Photosynthesis

• Photosynthesis is the process by which plants make carbohydrates and oxygen from carbon dioxide and water, using light energy.

6CO2 + 6H2O + energy C6H12O6 + 602

• Chlorophyll (the green colour in plants) is used to absorb the light energy.

Respiration

• Respiration is the process by which animals AND plants obtain the supply of energy that they need for growth, movement, warmth etc.

• They obtain this energy by breaking down the carbohydrate, glucose, using oxygen: C6H12O6 + 602 6CO2 + 6H20 +

energy

The Atmosphere

• The combination of respiration and photosynthesis lead to the balance of carbon dioxide/oxygen in the atmosphere.

• The clearing of forests with the loss of green plants, reduces the amount of photosynthesis taking place. This could alter the balance of the atmosphere, with a consequent danger to life on Earth.

Condensation Polymerisation

• Glucose monomers polymerise to form starch.

• Plants convert the glucose into starch for storing energy.

• This is a condensation polymerisation.

nC6H12O6 (C6H10O5)n + nH2O

Hydrolysis

• Hydrolysis takes place when large molecules are broken down into smaller molecules by the addition of small molecules, such as water.

• The breakdown of starch is an example of a hydrolysis reaction.

Digestion

• During digestion starch molecules are broken down by the body into smaller glucose molecules that can pass through the gut wall into the bloodstream.

• The breakdown of starch is brought about using acid or the enzymes, such as amylase.

• Sucrose and starch molecules break down by the addition of water:

C12H22O11 + H2O C6H12O6 + C6H12O6

sucrose glucose fructose(C6H10O5)n + nH2O n C6H12O6

starch glucose

Enzymes

• Enzymes, such as amylase, are biological catalysts

• An enzyme will work most efficiently within very specific conditions of temperature and pH.

• The further conditions are removed from the ideal the less efficiently the enzyme will perform.

Amino acids

• These are compounds which contain an amine group and an acid group.

N H

H

R

HO C C

O H

• There are about 25 essential amino acids.

• They are different because they have different side groups – shown by “R”.

• Condensation of amino acids produces the peptide (amide) link.

N H

H

R

HO C C

O H

The peptide link

• The peptide link is formed when an acid and amine join together. (We have previously called this the amide link.)

N H

H

R1

HO C C

O H

N H

H

R2

HO C C

O H

The peptide link

• The peptide link is formed when an acid and amine join together. (We have previously called this the amide link.)

N

H

R1

HO C C

O H

N H

H

R2

C C

O H

peptidelink

Proteins

• Proteins form an important class of food made by plants.

• They are condensation polymers made of many amino acid molecules linked together.

• The structure of a section of protein is based on the constituent amino acids.

• Proteins are used to make the main structures in animals – muscles, tissues etc.

• They also make important chemicals needed for the main processes of life such as enzymes, antibodies and hormones.

• Examples of these proteins are insulin and haemoglobin.

Amino acids polymerising

N H

H

R1

HO C C

O H

N H

H

R2

HO C C

O H


N

H

R1

HO C C

O H

N H

H

R2

C C

O H

H2O

N H

H

R3

HO C C

O H


N

H

R1

HO C C

O H

N

H

R2

C C

O H

H2O

N H

H

R3

C C

O H

H20

N H

H

R4

HO C C

O H


N

H

R1

HO C C

O H

N

H

R2

C C

O H

H2O

N

H

R3

C C

O H

H20

N H

H

R4

C C

O H

H2O

Digestion

• During digestion enzymes hydrolysis the proteins in our diet to produce amino acids.

• The body then builds up the proteins it needs from those amino acids.

Fats and Oils

• Natural fats and oils can be classified according to where they come from:

• Animal• Vegetable• Marine

• Fats and oils in the diet supply the body with energy.

• They are a more concentrated source of energy than carbohydrates.

• Oils are liquids and fats are solids.• Oils have lower melting points

than fats. • This is because oil molecules have

a greater degree of unsaturation.

Saturated fats:

have more regular shapes than unsaturated oils:

This means that fat molecules fit together easily and have a low melting point

Oil molecules do not fit together easily and have a high melting point

Oils can be converted into hardened fats by adding of hydrogen.

H2

H2

H2

Oils can be converted into hardened fats by adding of hydrogen.

This is how margarine is made

Fatty acids

• Fatty acids are straight chain carboxylic acids, usually with long chains of carbon atoms.

• Fatty acids may be saturated or unsaturated.

• Fats and oils are esters.• They are made from the triol

glycerol

CH2 OH

CH OH

CH2 OH

glycerol

and fatty acids.

R C OH

Ofatty acid

• Fats and oils are esters.• They are made from the triol

glycerol

CH2 OH

CH OH

CH2 OH

glycerol

and fatty acids.

fatty acid

HO C R

O

HO C R3

O

CH2 OH

CH OH

CH2 OH

HO C R2

O

HO C R1

O

Three fatty acids form esters with the three OHgroups of glycerol.

C R3

O

CH2 O

CH

CH2 O

O C R2

O

C R1

O

Three fatty acids form esters with the three OHgroups of glycerol.

• The hydrolysis of fats and oils produces fatty acids and glycerol in the ratio of three moles of fatty acid to one mole of glycerol.

C R

O

CH2 O

CH

CH2 O

O C R

O

C R

OCH2 OH

CH OH

CH2 OH

R C OH

O

+ 3

Natural Products

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The End

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