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Flashcards in Organic Chemistry II Deck (181):
1

What does organic menan?

'from living things'

2

What is organic chemistry?

the study of carbon compounds  - living or once living

3

What is a hydrocarbon?

a molecule made up of hydrogen and carbon atoms only

4

Where are hydorcarbons found?

in crude oil

5

What are alkanes?

they are the simplest hydrocarbons

they have a central chain of carbon atoms, joined by carbon-carbon signle bonds, surronded by hydrogen atoms

 

6

Different alkanes have chains of ... lengths

Different alkanes have chains of different lengths

7

What are the first five alkanes?

methane: CH4 

ethane: C2H6

propane: C3H8

butane: C4H10

8

How do you remember the names of alkanes and alkenes after butane/ene?

they take on the names of their mathematical shapes

5C = pentene/ane

6C = hexene/ane

7C = heptene/ane

8C = octene/ane

9

What is the displayed formula for methane?

10

What is the displayed formula for ethane?

11

What is the displayed formula for propane?

12

What is the displayed formula for butane?

13

What is the displayed formula for pentane?

14

Are alkanes saturated or unsaturated hydrocarbons?

saturates

they contain the maximum possible number of hydrogen atoms for a given number of carbons

 

15

What is methane a major component of?

natural gas

16

Alkanes are the simplest ...

homologous series

17

What is a homologous series?

a group of compounds with similar properties because they have similar bonding

they can all be represented by the same general formula

they have the same functional group

they have the same number of electrons on the outer shell

they have similar chemical reactivity

they are differentiated by CH2 group

18

What is the general formula of alkanes?

CnH2n+2

e.g. butane = C4H10 because it has four carbons so it has to have (2 x 4) + 2 hydrogens

19

What bonds do carbon and hydrogen form? How many can these atoms form?

carbon and hydrogen form covalent bonds

carbon can form four covalent bonds

hydrogen can form one covalent bond

20

The first four alkanes are ... at room temperature. All the other ones you are likely to come across at GCSE are ... . Alkanes are ... around C17H36

The first four alkanes are gas at room temperature. All the other ones you are likely to come across at GCSE are liquids . Alkanes are solids around C17H36

21

As alkanes get bigger, what increases between them? What does this mean?

 the intermolecular forces

this means that more energy has to be put in to break the attractions between one molecule and its neighbours

22

Are alkanes reactive?

they are very unreactive because they have strong covalent bonds

23

Where do you find alkanes?

in crude oil

24

What is the written equation for the complete combustion of any alkane? When does complete combustion occur?

alkane + oxygen → carbon dioxide + water (+ energy)

this occurs when there is enough oxygen

25

Complete combustion releases ... and only produces two ... . When there's ... and combustion is complete, the gas burns with a ... flame.

Complete combustion releases lots of energy and only produces two harmless waste products (carbon dioxide and water) . When there's plenty of oxygen and combustion is complete, the gas burns with a clear blue​ flame.

26

Explain why the combustion of hydrocarbon fuels is believed to by some scientists to be responsible for global warming

Include one effect of global warming in your answer

carbon dioxide and water vapour are one of the main greenhouse gases

it rises into the atmosphere but traps all the air so it is re-emmited back out again

one effect of global warming is the melting of ice caps which causes flooding

27

What is the balanced equation for the complete combustion of methane?

methane + oxygen → carbon dioxide + water

CH4 + 2O2 → CO2 + 2H2O

28

When does incomplete combustion of an alkane occur?

when there isn' enough oxygen

29

Is incomplete combustion of an alkane safe? Why?

no

carbon monoxide or carbon (soot) is produced instead of carbon dioxide

30

State three things that carbon monoxide is

colourless

odourless

very poisonous

31

Why is carbon monoxode poisonous?

it combines with haemoglobin (the molecule that carries oxygen in the blood stream), preventing it from carrying oxygen

you are made ill, or even die, because not enough oxygen gets to the cells in your body

32

What colour is the flame in incomplete combustion?

smoky yellow

33

What is the balanced equation for the incomplete combustion of methane?

methane + oxygen → carbon monoxide + water
2CH4(g) + 3O2(g) → 2CO(g) + 4H2O(l)

34

What is made when halogens react with alkanes?

haloalkanes

35

Halogens, such as chlorine and bromine react with alkanes in the presence of ... (e.g. ...). This is called ...

Halogens, such as chlorine and bromine, react with alkanes in the presence of ultra-violet light (e.g.sunlight). This is called photolysis

36

Halogens have ... bonds that are ... to break by U.V. light

Halogens have weak bonds that are easy to break by U.V. light

37

Do alkenes undergo photolysis?

No, only alkanes

38

What type of reaction is making haloalkanes by reacting chlorine or bromine with alkanes? Expalin this

a substitution reaction

a hydrogen atom from the alkane is substituted (replaced) by chlorine or bromine

39

A mixture of bromine and methane is the colour ... because ... . If exposed to U.V. light, such as sunlight, what is formed and what happens to the colour?

A mixture of bromine and methane is the colour brown because of the presence of the bromine . If exposed to U.V. light, such as sunlight, bromomethane and hydrogen bromide gas is formed and the colour is lost

40

Alkenes are ... but are different to alkanes because they have ... bonds

Alkanes are hydrocarbons but are different to alkanes because they have C=C carbon double​ bonds

41

Are alkenes saturated or unsaturated?

unsaturated

this is because they contian a double carbon bond

42

How do you obtain alkenes?

from cracking alkanes

43

What is cracking?

the process where a long chain alkane is broken down from larger molecules into smaller molecules; more useful alkanes and alkenes

44

What are the first three alkenes?

ethene: C2H4

propene: C3H6

butene: C4H8

45

What is the displayed formula for ethene?

46

What is the displayed formula for propene?

47

What is the displayed formula for butene?

48

What is the general formula for alkenes?

C2H2n

49

The first four alkenes are ... at room temperature. All the other ones you are likely to come across at GCSE are ... . Alkenes are ... around C17H34

The first four alkenes are gas at room temperature. All the other ones you are likely to come across at GCSE are liquids . Alkenes are solid around C17H34

50

In the complete combustion of alkenes, what is formed?

carbon dioxide and water

51

What is made when halogens react with alkenes?

haloalkenes

52

Alkenes undergo ... reactions. What does this entail?

Alkenes undergo addition reactions

part of the double bond breaks and the electrons are used to join other atoms onto the two carbon atoms

53

For bromine to add to alkenes, heat or a catalyst is/isn't needed

For bromine to add to alkenes, heat or a catalyst isn't needed

54

What is often used to test for carbon-cabon double bonds? Explain how this test works

the reaction between bromine and alkenes is often used

when you shake an alkene with orange bromine solution ('bromine water'), the solution becomes colourless

this is because the bromine molecules, which are orange, are reacting with the alkened to make dibromoalkane, which is colourless

55

What do alcohols belong to?

a homologous series

56

What group do alcoholes all contain?

an -OH group

e.g. ethanol is C2H5OH

57

How are alcohols bonded?

they are covalently bonded onto a carbon chain

58

What is the familiar alcohol in drinks? What is its chemical formula?

ethanol - C2H5OH

59

What is the general formula for alcohols?

CnH2n+1OH

60

The best way to make ethanol often depends on ...

The best way to make ethanol often depends on what resource is most easily available - oil or sugar

61

What are the two different methods of producing ethanol?

fermentation

hydration of ethene

62

Is yeast a chemical?

yeast is not a chemical but a microorganism

N.B. do not write it as a molecule in a formula but instead out it over the arrow

63

How is ethanol produced by fermentation?

yeast is added to a sugar or starch solution and left for several days in the warm (30-40oC) with the absence of air (anaerobic conditions)

enzymes (biological catalysts) in the yeast convert the sugar into ethanol and carbon dioxide

64

Explain the biochemistry of how ethanol is made by fermentation

ordinary sugar (sucrose) is split into two smaller sugars: glucose and fructose

glucose and fructose have the same molecular fomulae, but are differet structures (they are isomers)

enzymes in the yeast convert these sugars into ethanol and water

  • C12H22O11 (aq) (sucrose) + H2O (l) (water) → C6H12O6 (aq) (glucose) + C6H12O6 (aq) (fructose)
  • C6H12O6 (aq) (glucose) → 2C2H5OH (aq) (zymase) + 2CO2 (g) (carbon dioxide)

 

65

Is it possible to make pure ethanol by fermentation? Why?

no, it is impossible

yeast is killed by +15% of alcohol in the mixture

instead, the alcohol is purified by fractional distillation - this takes advantage of the difference in boiling point between ethanol (78oC) and water (100oC)

the liquid distilling over 78oC is 96% pure ethanol and the rest is water - it is impossible to remove this last 4& of water by simple distillation

66

Which resources are used in the production of ethanol by fermentation?

renewable resources

sugar beet or sugar cane, corn and other starchy materials

67

Which type of process is used in the production of ethanol by fermentation?

a batch process

everything is mixed together in a reaction vessel, then left for a several days

that batch is removed and a new reaction is set up

this is inefficient

68

What is the rate of reaction of the production of ethanol by fermentation?

very slow, taking several days for each batch

69

What is the quality of ethanol produced by fermentation?

very impure - needs further processing

not very concentrated - needs to be distilled to increase its strength (as in whiskey distilleries)

70

What are the reaction conditions used in the production of ethanol by fermentation?

gentle temperatures (about 30oC)

simple, cheap equipment

ordinary pressures

71

Is sugarand yeast easily grown?

yes

sugar (sugar cane) is grown as a major crops in several parts of the world, including poorer countries

72

The alcohol in beer and wine etc... is made by ...

The alcohol in beer and wine etc... is made by fermentation

73

How is ethene produced?

by cracking crude oil

74

What is meant by 'hydration' of ethene?

reacting ethene with steam

75

What is the equation for the hydration of ethene?

76

What are the starting materials in the production of ethanol by the hydration of ethene?

ethene and steam

77

What is the temperature in the production of ethanol by the hydration of ethene?

300oC

78

What is the pressure in the production of ethanol by the hydration of ethene?

60 - 70 atmospheres

79

What is the catalyst in the production of ethanol by the hydration of ethene?

phsophoric acid - H3PO4

80

In the production of ethanol by the hydration of ethene, how much ethene reacts? What happens to the unreacted ethene?

only a small proportion of ethene reatcs

the unreacted ethene is recyled through the process

81

In the production of ethanol by the hydration of ethene, what happens to the ethanol produced?

it is condensced as a liquid

82

Which resources are used in the In the production of ethanol by the hydration of ethene?

finite resources (ethene from oil)

once all the oil has been used up there won't be any more

83

Which type of process is used in the production of ethanol by the hydration of ethene?

a continuous flow process

a stream of reactants is constantly passed over the catalyst

this is more efficient than a batch process

84

What is the rate of reaction of the production of ethanol by the hydration of ethene?

rapid

85

What is the quality of ethanol produced in the by the hydration of ethene?

a much purer ethanol

86

What are the reaction conditions used in the production of ethanol by the hydration of ethene?

high temperatures: 300oc

high pressures: 60 - 70 atmospheres

needs a high input of energy

 

87

What is the difference is labour costs between the production of ethanol by fermentation and hydration of ethene?

fermentation: high labour costs

hydration of ethene: low labour costs

88

What do alcohols produce when they burn?

carbon dioxide and water

89

What is meant by 'dehydration' in the dehydration of alcohol

the removal of water from a compound

90

What is the equation for the dehydration of ethanol to form ethene?

91

How is ethanol dehydrated to form ethene?

ethanol vapour is passed ober a hot catalyst of aluminium oxide, Al2O3

the catalyst provides a large surface area for this reaction

92

Crude oil is burned for ... but this can produce ...

Crude oil is burned for energy but this can produce pollutants

93

How was crude oil formed?

crude oil was formed millions of years from remains of dead organisms (dead sea creatures)

huge numbers of microscopic animals and plants died and fell to the bottom of the sea - their remains were covered in mud

layers of sediment formed on top of them and their shells and skeletons formed limestone

the soft tissue was gradually changed by high temperatures and pressures into crude oil

crude oil is less dense than the water in rocks so it will rise as a result of pressure from below and often escape altogether if the rocks are permeable

(if the rocks are impermeable, oil can't rise through and gets trapped)

94

What type of resource is curde oil?

a finite, non-renewable resource

95

What is crude oil?

a mixture of substances, most of which are hydrocarbons

96

As hydrocarbons increase their molecular size, what happens to their boiling points? Why?

as the molecules get bigger, the boiling point increases

large molecules are attracted to each other more strongly than smaller ones

more heat is needed to break these stronger attractions to produce the widely separated molecules in the gap

97

As hydrocarbons increase their molecular size, what happens to their volatility? Why?

as the molecules get bigger, the liquids become less volatile (the more slowly it evaporates at room temperature)

this is because bigger molecules are more strongly attracted to their neighbours and so don't turn turn to a gas so easily

98

What does volatility mean?

the tendency of a substance to vaporize

99

As hydrocarbons increase their molecular size, what happens to their viscosity? Why?

as the molecules get bigger, they become more viscous (flow less easily) 

liquids containing small hydrocarbon molecules are runny

those containing large molecules are much stickier because of greater attractions between their molecules

100

Which burn more easily, bigger or smaller hydrocarbons? What does this mean for their use?

bigger hydrocarbons do not burn as easily as their smaller ones

this limits the use of the bigger ones as fuels

101

How are the different compounds in crude oil separated?

by fractional distillation

102

What are the steps of fractional distillation?

1.  The oil is heated until most of it has turned into gas. The gases enter a fractionalating column  (and the liquit bit, bitumen, is drained off at the bottom)

2. In the column there's a temperature gradient (it's hot at the bottom and gets gradually cooler as you  as you go up). When the substances that make up crude oil  reach the part of the column where the temperature is lower than their boiling point they condense (turn back into a liquid)

3. The longer hydrocarbons have high boiling points. They condense and drain out of the column early on, when they're near the bottom

4. The shorter hydrocarbons have lower boiling points. They turn into liquid and darin out much later on, near the top of the column where it's cooler

5. Bubble caps in the fractioning column stop the separated liquids from running back down the column and remixing. You end up with the crude oil separated into different fractions. Each fraction contains a mixture of hydrocarbons with similar boiling points.

103

What are the fractions in fractional distillation in order of shortest to longest hydrocarbons

Refinary gases

Gasoline (petrol)

Naptha

Kerosene (paraffn)

Diesel

Fuel oil (gas oil)

Bitumen

104

As fractions increase in density and boiling point in fraction distillation, what becomes of them?

more carbon atoms

less commercially useful

105

What is the approximate number of carbons in the hydrocarbon chain of refinary gases?

4 carbons

106

What is the approximate number of carbons in the hydrocarbon chain of gasoline?

8 carbons

107

What is the approximate number of carbons in the hydrocarbon chain of naptha?

10 carbons

108

What is the approximate number of carbons in the hydrocarbon chain of kerosene?

15 carbons

109

What is the approximate number of carbons in the hydrocarbon chain of diesel?

20 carbons

110

What is the approximate number of carbons in the hydrocarbon chain of fuel oil?

40 carbons

111

What is the approximate number of carbons in the hydrocarbon chain of bitumen?

70+ carbons

112

What type of process is fractional distillation?

a physical process - there are no chemical reactions

113

What are the uses of refinary gases?

commonly used as liquefied petroleum gas (LPG) for domestic heating and cooking

 

114

What are the uses of of gasoline?

fuel (petrol) for cars

115

What are the uses of naptha?

used in the chemical industry as a 'feedstock' (starting material) to make: plastics; dyes; drugs; explosives; paints

116

What are the uses of kerosene?

fuel for jet engines

domestic heating oil

'paraffin' for small heaters and lamps

117

What are the uses of diesel?

fuels for enginesin some cars, buses, lorries, boats and railways engines where the line hasn;t been electrified

some is also cracked to make other organic chemicals and produce more petrol

118

What are the uses of fuel oil?

domestic central heating

fuel for big ships

boilers for ships

119

What are the uses of bitumen?

melted and mixed with rock chippings to make surfaced for roads and asphalt for roofs

120

What are two problems with fractions form crude oil distillation?

1. The amounts of each fraction you get will depend on the properties of the various hydrocarbons in the original crude oil, not the amount in which they are needed. Far more petrol is needed, for example, than is found in crude oil

2. Apart from burning, the hydrocarbons in crude oil are fairly unreactive. To make other organic chemicals from them, they must first be converted into something more reactive

121

Why do we crack long hydrocarbons?

they are not very useful

122

Long hydrocarbons have ... boiling points are are (volatile/viscous)

Long hydrocarbons have high boiling points are are viscous

123

Shorter hydrocarbons have ... boiling points and are much (thinner/thicker) and ... in colour

Shorter hydrocarbons have low boiling points and are much thinner and paler ​in colour

124

What is cracking a form of? Explain this

cracking is a form of thermal decomposition because the larger molecules are broken down into simpler molecules by heating them

125

How does cracking work?

the gas oil fraction is heated to give a gas

vaporised hydrocarbons are passed over a powdered catalyst of mixed silicon dioxide/silica (SiO2) and aluminum oxide (Al2O3) at about 600oC to 700oC

126

What does cracking produce?

amixture of alkanes and alkenes

some reactions even produce a small percentage of free hydrogen

127

Cracking breaks up molecules in a ... way

Cracking breaks up molecules in a fairly random​ way

128

What are the steps of cracking paraffin?

1. Start by heating the paraffin. After a few seconds, move the Bunsen burner to heat the silica or alumina catalyst. Alternate between the two until the paraffin vaporises and the catalyst glows red

2. The heated paraffin vapour cracks as it passes over the heated catalyst

3. Smaller alkanes collet at the end of the boiling tube, while alkene gases travel down the delivery tube

4. The alkenes are then collected through water using a gas jar

129

What are two things cracking is useful for?

making alkenes for plastics

turning bitumen and candle wax (of limited use) into things like petrol and cooking gas (which are very useful)

130

What is polymerisation?

the joining up of lots of little molecules (the monomers) to make one big molecule (the polymer)

131

What two types of polymer are there?

addition

condensation

132

A polymer is a chemical ... made of ... (called ...) linked together

A polymer is a chemical compound made of many smaller, identical molecules (called monomers) linked together

133

What is additional polymerisation?

Under high pressure and with a cataylst to help them along, many small molecules containing a carbon-carbon double bond will open open up (break) the double bonds and join together (polymerise) to form very long, saturated chains - polymers

134

In addition polymerisation, ... add to themselves

As this addition proceeds further a ... is formed

The alkene is a ... in the chain (the monomer) - the chain itself is the ...

In addition polymerisation, alkenes add to themselves

As this addition proceeds further a long, molecular chain is formed

The alkene is a repeating unit in the chain (the monomer) - the chain itself is the polymer

135

What is the displayed formula or ethene becoming poly(ethene)

136

How do you find the repeat unit of a polymer?

find the section of the polymer that's repeated

137

How do you name a polymer?

the name comes from the monomer it's made from - you just put brakets around the monomer and stick the word 'poly' in front of it

e.g. poly(ethene)

138

How do you find the monomer used to form an addition polymer?

take the repeat unit and add a double bond

139

How are plastics formed?

plastics are formed when lots of small molecules (monomers) join together to make a polymer

140

Are polymers hard or easy to get rid of?

most polymers are hard to get rid of

141

Why are most polymers hard to get rid of?

most addition polymers are inert (they don't react easily) - this is because of the carbon-carbon covalent bonds in the polymer chain are very strong and aren't broken down easily

this means that it takes a really long time for addition polymers to biodegrade (be broken down by bacteria or other living organisims) - if you bury them in a landfill site, they'll stil be there years later

burning plastics can release toxic gases

142

What is the best thing to do with polymers in terms of disposal?

it is difficult to dispose of polymers

the best thing is to reuse them as many times as possible and then recycle them

143

What two types does poly(ethene) come in?

low density poly(ethene) (LDPE)

high density poly(ethene) (HDPE)

144

What is low-density poly(ethene) mainly used for? Why?

thin film to make polythene bags

it is very flexible and light but not very strong

145

What is high-denisty poly(ethene) used more? Why?

plastic bottles such as milk bottles

it hs rather greater strengh and rigidity than low-density poly(ethene)

146

What is poly(ethene) used for? Why?

packaging such as plastic bags, bottles and other containers

it is a light, stretchable polymer

147

What is the is the product of the polymerisation of propene?

poly(propene)

148

What is the displayed formula for poly(propene)?

149

What are the uses of poly(propene)? Why?

ropes

crates

kettles

food containers

carpets

it's a very tough polymer, but it's relatively flexible and resistant to heat

150

What is the prodcut of the polymerisation of chloroethene? What is it commonly known as?

poly(chloroethene)

it is usually known by is old name, polyvinlychloride or PVC

151

What is the displayed formula for poly(chloroethene)

152

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

it is quite strong and rigid: drainpipes, replacement windows

it can be made flexible by adding 'plasticisers': sheet floor coverings

it doesn't conduct electricity: insulating electrical cables

153

What is condensation polymerisation?

it usually involves two differnt types of monomer joining together alternately

the monomers react together and bonds form between them, making polymer chains

for each new bond that forms, a small molecule (for example, water) is lost

154

What is the functional group for carboxylic acid? What is an example of carboxylic acid?

-COOH group

e.g. ethanoid acid in vinegar = CH3COOH

155

Ask her about condensation polymersiation and nylon!!! must make notes on pg.172-173 from textbook

156

What is a structural formula?

it shows how the atoms are joined up

it can be either be drawn as displayed formula or written out as, for example, CH3CH2CH3 (C3H8)

157

What do each of the lines in displayed formulae represent?

a pair of shared electrons

158

What is the displayed formula of methane?

159

What is the displayed formula of ethane?

160

What is the displayed formula of propane?

161

What is the displayed formula of butane?

162

What is the displayed formula of ethene?

163

What is the displayed formula of propene?

164

What is the displayed formula of butene?

165

How do you name organic compounds?

1. identify the largest carbon chain

2. number from heaviest side first - a double bond is heaviest (so put it on lowest carbon possible), read left to right or right to left to which carbon 

3. identify groups attached - e.g. 1C = methyl

4. identify type of molecule

5. prefix (group) - suffix (type) 

166

What is the name of this formula: CH2=CHCH2CH3?

but-1-ene

167

What is the name of this formula: CH3CH=CHCH3?

but-2-ene

168

What is the displayed formula of methanol?

169

What is the displayed formula of ethanol?

170

What is the displayed formula of propanol?

171

What is the displayed formula of butanol?

172

What is the displayed formula of pentanol?

173

What does '2,3-dimethyl' mean?

there are two methyl groups attached to the second and third carbon atom in the chan

174

What are sturctural isomers?

molecules with the same molecular formula, but with different structural formulae

175

Do methane, ethane and propane have any isomers?

no

176

What are the isomers of butane? Which structural isomer has a higher boiling point and why?

number 1 as it has higher intermolecular force of attraction as the chain is a straight line - it harder to break

177

What are the isomers of pentane? Name them

178

Do ethene and propene have isomers?

179

What are the isomers of butene?

180

What are the isomers of pentene?

181

How do you make sure not to draw the same isomer?

draw the longest carbon chain horizontally