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Chemistry Year 11 IGCSE > 4.5 - 4.8 - Organic part 2 > Flashcards

4.5 - 4.8 - Organic part 2 Flashcards

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1
Q

What are the four alcohols looked at in organic chemistry?

A

methanol
ethanol
propan-1-ol
butan-1-ol

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2
Q

What are the molecular formulas of all the alcohols?

A

methanol- CH4o
ethanol- C2H6o
prop-1-ol- C3H8o
buttan-1-ol - C4H8o

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3
Q

What does the an mean in all of the alcohols

A

The molecule is saturated and there is no carbon carbon double bonds

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4
Q

What is the structural formula of all of the alcohols?

A

methanol- CH3OH
ethanol - CH3CH2OH
prop-1-ol - CH3CH2CH2OH
butan-1-ol -CH3CH2CH2CH2OH

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5
Q

What is the displayed formula of all the alcohols?

A
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6
Q

What is a functional group?

A

A group of atoms that give characteristic reactions of a particular group

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7
Q

What is a homogolus series and what are its properties?

A

A family of organic compounds with the same functional group is called a homologous series
-Same general formula
-Same functional group
-Each member differs by -CH2
-Similar chemical properties
-Patterns of physcial properties

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8
Q

What is the functional group and general formula of alcohol?

A

Functional group- OH
General formula- CNH2N+1OH

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9
Q

Why does alcohol oxidise in air?

A

All alcohols burn to form carbon dioxide and water.
C2H5OH+ 3O2 > 2CO2 + 3H20
Ethanol is a biofuel made up from biological sources such as sugar cane or corn. Mixtures of petrol with ethanol are used in countries like Brazil. Places like these have little oil to produce fuel so use this to produce own fuel. They also have a good climate for growing sugar cane.

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10
Q

How can ethanol be oxidised by air in the presence of microbes?

A

Bottle of wine left open in the air turns sour. Ethanol in wine is oxidised by the air with the help of microorganisms with the help of bacteria of yeast to form ethanoic acid. CH3COOH.

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11
Q

How can ethanol be oxidised by heating with potassium dichromate in dilute sulfuric acid?

A

Usual way of oxidising ethanol in the lab. The oxidising agent is a mixture of potassium dichromate and dilute sulfuric acid. Potassium DC, is a strong oxidising agent. The dilute sulfuric acid is important for the pottasium DC to act as a oxidising agent. Without the H+ ions from the acid no redox reaction occours

A few drops of ethanol are added to a solution containing the orange mixture of pottasium DC and dilute sulfuric acid. Tube is heated in a hot water bath.

Solution turns green and contain a dilute solution of ethanoic acid with other products. Green colour indicates the presence of CR3+ ions. formed when pottasium DC is reduced. The oxidising agent is known as [O]

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12
Q

How is fermentation used to produce ethanol?

A

Yeast is added to a sugar solution and left in the warm for several days in the absence of air. Enzymes in the yeast convert the sugar into ethanol and carbon dioxide known as fermentation.

Absence of air and temp are important. In the presence of air enzymes in the yeast produce carbon dioxide and water instead of ethanol. enzymes are protein catalyst and if the temp isn’t above 40 lose their structure and become denatured. somewhere between 30-40 is optimum.

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13
Q

How is pure alcohol formed?

A

Yeast is killed by more than about 15% of alcohol in the mixture. Impossible to made pure. Alcohol is purified by fractional distillation. takes advantage of boiling points between ethanol and water

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14
Q

How is Ethanol formed by hydration of ethane?

A

Reacting ethene with steam produces ethanol. Catalyst phosphoric acid. Only a small proportion of the ethene reacts. Ethanol produced in a condensed liquid and the unreacted ethene is recycled through the process. Tempreture is about 300oc and pressure at about 60-70 atmospheres.

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15
Q

Explain the differences between the two methods of producing Ethanol

A

Use of resources - Fermentation, Uses renewable resources sugar cane corn and other starchy materials.
Use of resources - Hydration of ethane, Uses finite non- renewable resources once al the oil is consumed, there wont be any more

Type of process- Fermentation, A batch process everything is mixed together in a reaction vessel and left for several days. Batch is then removed and a new reaction is set up.
Type of process- Hydration of ethane, a continuous flow process a stream of reactants is constantly passed over the catalyst, more efficient batch process.

Rate of reaction and quality of process- Fermentation, Slow takes several days for each batch, produces very impure ethanol which needs further processing.
Rate of reaction and quality of process- Hydration of ethane, Quick process and produces very pure ethanol

Reaction conditions- Fermentation, Uses gentle tempretures and atmospheric pressure.
Reaction conditions- Uses high tempretures and pressures requiring a higher input of energy.

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16
Q

What is the equations for the production of ethanol

A

fermentation- C6H12O6 >2C2H5OH +2CO2
hydration of ethene- CH2+ H20 >CH3CH2OH

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17
Q

What are the equation’s for the oxidation for ethanol?

A

Microbes in air- CH3CH2OH + O2 > CH3COOH +H2O
Ethanol burning in air- C2H5OH + 3O2 > 2CO2 + 3H20
Heating with potassium dichromate in dilute sulphuric acid- CH3CH2OH +2[O] > CH3COOH +H20

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18
Q

What is the functional group of carboxylic acid?

A

Acids such as ethanoic acid and are known as carboxylic acid are I the function group -COOH

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19
Q

How are Carboxylic acid formed?

A

Formed by oxidation of the corresponding alcohols, for example ethanoic acid is formed when ethanol is left in the air or oxidised using dichromate in dilute sulfuric acid.

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20
Q

What is the molecular formula of all of the carboxylic acid?

A

Methanoic acid - CH2O2
Ethanoic acid - C2H4O2
Propanoic acid - C3H6O2
butanoic acid - C4H8O2

21
Q

What is the structual and displayed formula of the carboxylic acid?

A

Methanoic acid- HCOOH
Ethanoic acid- CH3COOH
Propanoic acid - CH3CH2COOH
Butanoic acid - CH3CH2CH2COOH

22
Q

What are the properties of carboxylic acid?

A

Ethanoic acid and the other carboxylic acid are weak acids only partially dissociates in water. with a pH of about 3-5, depending on concentrations of the solution/, turning blue litmus paper red and react with all the things acids react with.
An aqueous solution containing ethanoic acid known as vinegar

23
Q

What happenes in a reaction between Carboxylic acid and metals?

A

Dilute ethanoic acid reacts with metals for example ethanoic acid reacts with magnesium with a lot of fizzing to produce a salt and water
Acid + metal > salt + water

Mg + 2CH3COOH > (CH3COOH)2MG +H2

24
Q

What happenes in a reaction between a Carboxylic acid and carbonates?

A

Carbonates + acid > salt + co2 + h20

25
Q

What are esters?

A

Esters are organic compounds formed by a reaction of an alcohol with a carboxylic acid
Their functional group is -COO-

26
Q

How is it possible to make a simple ester : ethyl ethanoate?

A

Heating a mixture of ethanoic acid ad ethanol with a few drops of concentrated sulfuric acid produces ethyl ethanoate.
The reaction is called esterification and can be described as condensation reaction with water is made when two molecules are joined together.
This reaction is reversible so to maximise the yield of ethyl ethanoate often use pure ethanol and ethanoic acid if water is added to the reactants the system would want to shift to the left to consume the water and decrease the amount of ethyl ethanoate made.

27
Q

What are some of the uses of esters?

A

The small esters like ethyl ethanoate are used in solvents, most esters are used in food flavouring and perfumes. They are volatile liquids with distinctive smells. Typically smell of bananas and raspberries all different fruits.

28
Q

What is the structure of ethene?

A

Ethene is the smallest alkene and can be produced by cracking. It is the smallest hydrocarbon containing carbon-carbon double bond.

29
Q

What is polymerisation?

A

Polymerisation is the joining up of lots of monomers to make a big polymer. In the case of ethene, lots of ethene molecules join together to make a polyethene, usually known as polythene. molecules simply add onto each other without anything else being formed known as an additional polymerisation.

30
Q

How long can a polymer chain be?

A

Chain length can vary from about 4,000 to 40,000 carbon atoms.

31
Q

What are some uses for Poly(Ethene)?

A

Poly(ethene) comes into two types: low density poly(ethene) (LDPE) and high density poly(ethene) (HDPE).

(LDPE) is mainly used as a thin film to make polythene bags. It was very flexible and not very strong

(HDPE) is used where greater strength and ridged are needed, like making plastic bottles and milk bottles.

32
Q

What happenes in the Polymerisation of propene?

A

Propene is another alkene, this time with there carbon atoms in each molecule. The formula is normally is usually written as CH3CH=CH2..

When propene is polymerised poly(propene) . This is called polypropylene.

33
Q

What is the uses of Poly(propene)?

A

Poly(propene) is a bit stronger than poly(ethene) it is used to make ropes and creates. Can be recycled.

34
Q

What happenes in the Polymerisation of Chloroethene?

A

Chloroethene is a molecule in which one of the hydrogen atoms in ethene is replaced by a chlorine. Its formula is CH2=CHCI. Polymerising chloroethene gives poly(chloroethene knows as PVC

35
Q

What are some of the uses of poly(chloroethene)?

A

Poly(chloroethene) known as PVC has a lot of uses. It is quite strong and rigid, so can be used for water pipes or replacement windows. It can also be made flexible by adding plasticisers. This makes it useful for sheet and floor coverings and sometimes clothing. Polymer does not conduct electricity. Therefore PVC can be used for electrical insualtion.

36
Q

What happenes in the Polymerisation of Tetrafluoroethene?

A

Tetrafluoroethene is another molecule derived from ethene is which all four hydrogen atoms are replaced by fluorine its formula is CF2=CF2. Polymerising tetrafluoroethene gives you poly(Tetrafluoroethene) or PTFE.

37
Q

What are some of the uses of poly(Tetrafluoroethene)?

A

poly(Tetrafluoroethene) is often used as a non stick coating for pots and pans. It is very unreactive due to the strong carbon-fluorine bonds, and can be found lining containers for corrosive chemicals.

38
Q

Why is it important to recycle and dispose of plastics?

A

It is very important to recycle plastics because it takes a very long time for addition polymers like poly(ethene) and poly(chloroethene) to break down the environment. They contain strong covalent bonds making them essentially inert at ordinary tempretures they are non-biodegradable cannot be broken down by bacteira in the environment.

39
Q

How do landfill sites solve the problem of disposal of addition polymers?

A

Advantages: No greenhouses gases or toxic gases produced from plastics
very cheap.

Disadvantages: Ugly smelly and noisy people don’t want to live next to a landfill site. It uses large areas of land. The waste will be there for thousands of years.

40
Q

How do Incineration solve the problems of disposal of addition polymers ?

A

Advantages: Requires little space. Can produce heat for local homes and offices and produce electricity.

Disadvantages: It is expensive to built and maintain the plant. Produces greenhouse and toxic gases .
The ash produced must still be disposed of in landfill sights

41
Q

What is the definition of addition polymerisation

A

When a lot of molecules join together to make a chain the double bonds break and the monomer molecules just add onto each other to make a polymer. Nothing lost.

42
Q

What is a monomer?

A

A small molecule that can combine with other similar molecules to form a long molecule known as a polymer.

43
Q

What is a polymer?

A

Very long molecules made of smaller molecules called monomers.

44
Q

What are the conditions of Addition polymerisation?

A

During the polymerisation reaction the monomers are put under high pressure and high tempreture.

This causes the carbon double bonds to break in monomer.
Molecules are forced to close together by the high pressure.
New carbon-carbon single bonds are formed between monomers.

45
Q

What is Condensation Polymerisation?

A

Making polyester is different to addition polymerisation. Instead of one type of monomer often have two joining together alternately. Each time two monomers combine a small molecule such as water or hydrogen chlorine is lost the elimination of water gives the name condensation to this type of polymerisation.

46
Q

What are Biodegradable polyesters?

A

As with addition polymers there are environmental issues with the disposal of condensation polymers. These are more reactive because of the ester linkage and will break down eventually. Although this could take hundreds of years. Scientist have developed biodegradable polyesters.

Biodegradable polymers can be made from lactic acid. Lactic acid can be obtained from corn starch. When it undergoes polymerisation it forms a biodegradable polyester. Can be used for bags

47
Q

What are the diols?

A

One of the monomers is a diol an alcohol molecule with one -OH at each end. The code di shows that there are two -OH group presents.

48
Q

What are dicarboxylic acid?

A

A carboxylic molecule with one -COOH at each end .

Chemistry Year 11 IGCSE (20 decks)

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