Chains, Energy and Resources - Basic Concepts and Hydrocarbons Flashcards Preview

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Flashcards in Chains, Energy and Resources - Basic Concepts and Hydrocarbons Deck (156):
1

What do organic compounds contain?

All organic compounds contain carbon.

2

What are the simplest family of organic compounds?

The hydrocarbons are the simplest family of hydrocarbons.

3

Define a hydrocarbon.

Hydrocarbons are organic compounds that contain carbon and hydrogen only.

4

Where are almost all usable supplies of hydrocarbons obtained from?

Almost all usable supplies of hydrocarbons are obrained from fossil fuels.

5

How many known carbon compounds are there?

There is an excess of 10 million known carbon compounds.

6

How many new carbon compounds are estimated to be discovered each year?

Estimated 300,000 new carbon compounds are discovered each year.

7

Why can carbon form so many compounds?

Carbon can form so many compounds because:

  • a carbon atom can form bonds with other carbon atoms to make chains and rings
  • a carbon atom can form single, double or triple bonds to another carbon atom
  • a carbon atom can bond with atoms of other elements such as oxygen, hydrogen, nitrogen and phosphorous and the halogens

8

In which group of the periodic table would you find carbon?

Carbon is in group 4 of the periodic table.

9

How many outer shell electrons does carbon have?

Carbon has 4 outer shell electrons.

10

What type of bonds does a saturated hydrocarbon contain?

A saturated hydrocarbon contains single bonds only.

11

What type of bond will an unsaturated hydrocarbon contain?

An unsaturated hydrocabon will contain carbon-to-carbon multiple bonds.

12

Define an aliphatic hydrocarbon.

An aliphatic hydrocarbon is a hydrocarbon with carbon atoms joined together in straight or branched chains.

13

Define an alicyclic hydrocarbon.

An alicyclic hydrocarbon is a hydrocarbon with carbon atoms joined together in a ring structure.

14

Define functional group

A functional group is the part of the organic molecule responsible for its chemical reactions.

15

TRUE or FALSE

A saturated hydrocarbon tends to be incredibly reactive?

FALSE!

A saturated carbon chain has little chemical reactivity.

16

Define a homologous series.

A homologous series is a series of organic compounds with the same functional group but with each successive member differing by CH2.

17

What is the general formula of the alkanes?

Alkanes are the homologous series with the general formula CnH2n+2.

18

In an alkane, what is the shape around each carbon atom?

Each carbon atom in an alkane has a tetrahedral shape.

19

What is the bond angle in alkanes?

The bond angle in alkanes is 109.5o.

20

What is the name of a 1 carbon alkyl group?

The name of a 1 carbon alkyl group is methyl.

21

What is the name of a 2 carbon alkyl group?

A 2 carbon alkyl group is called ethyl.

22

What is the name of a 3 carbon alkyl group?

The name of a 3 carbon alkyl group is propyl.

23

What is the name given to a 4 carbon alkyl group?

The name of a 4 carbon alkyl group is butyl.

24

What is the name of a 5 carbon alkyl group?

A 5 carbon alkyl group is pentyl.

25

What is the name given to a 6 carbon alkyl group?

Hexyl is the name given to a 6 carbon alkyl group.

26

What is the name given to a 7 carbon alkyl group?

A 7 carbon alkyl group is known as heptyl.

27

What is the name given to an 8 carbon alkyl group?

Octyl is the name given to an 8 carbon alkyl group.

28

What name is given to a 9 carbon alkyl group?

A 9 carbon alkyl group is known as nonyl.

29

What is the name given to a 10 carbon alkyl group?

A 10 carbon alkyl group is known as decyl.

30

Define an alkyl group.

An alkyl group is an alkane with a hydrogen atom removed, eg CH3, C2H5.

31

What letter is generally used to represent alkyl groups?

An 'R' is generally used to represent alkyl groups.

32

If fluorine, chlorine, bromine and iodine groups were all attached to an alkane chain, in what order would they be listed?

Groups attached to an alkane chain are listed in alphabetical order.

33

Define an alkene.

An alkene is an unsaturated hydrocarbon with at least one carbon-to-carbon double bond, C=C.

34

What is important to remember when naming alkenes?

When naming alkenes, it is important to remember to state the position of the double bond.

35

Define the empirical formula.

The empirical formula is the simplest whole number ratio of atoms of each element present in a compound.

36

Define the molecular formula.

The molecular formula is the actual number of atoms of each element within a molecule.

37

Define a general formula.

A general formula is the simplest algebraic formula of a member of a homologous series. For example, the general formula of the alkanes is CnH2n+2.

38

What is the displayed formula?

A displayed formula shows the relative positioning of all the atoms in a molecule and the bonds between them.

39

What is a structural formula.

A structural formula shows the minimal detail for the arrangement of atoms in a molecule.

40

What is the skeletal formula?

The skeletal formula is a simplified organic formula, with hydrogen atoms removed from alkyl chains, just leaving the carbon skeleton and associated functional groups.

41

Define structural isomer.

Structural isomers are molecules with the same molecular formula but with different structural arrangements of atoms.

42

What are the three ways in which a structural isomer can occur?

  • hydrocarbon chain can be branched or unbranched
  • functional group can be in a different position on the hydrocarbon chain
  • functional groups may be different, but still result in the same molecular formula (eg propanal and propanone)

43

Define stereoisomer.

Stereoisomers are compounds with the same structural formula but with a different arrangement of the atoms in space.

44

Define e/z isomerism.

e/z isomerism is a type of stereoisomerism in which different groups attached to each carbon atom of a C=C double bond may be arranged differently in space because of restricted rotation of the C=C double bond.

45

Define cis-trans isomerism.

Cis-trans isomerism is a special type of e/z isomerism in which there is a non-hydrogen group and a hydrogen on each C of a C=C double bond.

46

TRUE or FALSE

For e/z isomerism, each carbon in a double bond must be attached to two different groups?

TRUE!

For e/z isomerism each carbon in a double bond must be attached to two different groups.

47

Define cis-trans isomerism.

Cis-trans isomerism is a special type of e/z isomerism in which there is a non-hydrogen group and hydrogen on each C of a C=C double bond.

48

Is the cis isomer e or z?

The cis isomer is Z.

49

Is the trans isomer e or z?

The trans isomer is E.

50

In which type of isomer are the hydrogen atoms on each carbon on the same side?

The cis (Z) isomer has the hydrogen atoms on each carbon on the same side.

51

In which type of isomer are the hydrogen atoms on each carbon on different sides?

In the trans (E) isomer, the hydrogen atoms on each carbon are on different sides.

52

In a chemical reaction, bonds are broken by what?

In a chemical reaction, bonds are broken by bond fission.

53

Define homolytic fission.

Homolytic fission is the breaking of a covalent bond, with one of the bonded electrons going to each atom, forming two radicals.

54

Define a radical.

A radical is a species with an unpaired electron.

55

Which symbol is used to signify that a species is a radical?

A single dot is often writeen next to the species to represent the unpaired electron.

56

Define heterolytic fission.

Heterolytic fission is the breaking of a covalent bond with both of the bonded electrons going to one of the atoms, forming a cation (+ ion) and an anion (- ion).

57

Define a nucleophile.

A nucleophile is an atom (or group of atoms) that is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.

58

Which species are often nucleophiles?

Nucleophiles are often negative ions with a lone pair of electrons.

59

Define an electrophile.

An electrophile is an atom (or group of atoms) that is attracted to an electron-rich centre or atom, where it accepts a pair of electrons to form a new covalent bond.

60

Which species are often electrophiles?

Electrophiles are often positive ions.

61

Define an addition reaction.

An addition reaction is a reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule.

62

Define a substitution reaction.

A substitution reaction is a reaction in which an atom or group of atoms is replaced with a different atom or group of atoms.

63

Define an elimination reaction.

An elimination reaction refers to the removal of a molecule from a saturated molecule to make an unsaturated molecule.

64

What is the percentage yield?

The percentage yield measures the proportion of products formed in a reaction.

65

What does the atom economy measure?

The atom economy measures the proportion of products that are used.

66

What is crude oil made from?

Crude oil is made from naturally decaying plants and animals that once lived in ancient seas, millions of years ago.

67

Generally, crude oil is a mixture of how many different hydrocarbons?

Generally, crude oil is a mixture of 150+ different hydrocarbons.

68

TRUE or FALSE

Most of the hydrocarbons in crude oil tend to be branched?

FALSE!

Most of the hydrocarbons in crude oil tend to be unbranched.

69

Define fractional distillation.

Fractional distillation is the separation of the components in a liquid mixture into fractions which differ in boiling point (and hence chemical composition) by means of distillation, typically using a fractionation column.

70

In a fractionation column, which hydrocarbons condense near the top?

In a fractionation column, short chain hydrocarbons with lower boiling points condense near the top of the column.

71

What happens to gases in a fractionation column?

Gases don't condense. they pass through an outlet.

72

What is the residue at the bottom of the fractionation column?

The residue from the process of fractionation is bitumen, which is removed from the bottom of the column.

73

What is bitumen used for?

Bitumen can be used in road surfacing and roof covering.

74

As the chain length of hyrocarbons increases, the boiling point ............... ?

As the chain length of hydrocarbons increases, the boiling point increases.

75

Why does the boiling point of hydrocarbons increase as the chain length increases?

The boiling point of hydrocarbons increases as the chain length increases because the intermolecular forces between the molecules get stronger. There are more points of contact between the molecules leading to more van der Waals' forces.

76

A branched isomer has a ....... lowing point than an unbranched isomer.

A branched isomer has a lower boiling point than an unbranched isomer.

77

Why does a branched isomer have a lower boiling point than an unbranched isomer?

A branched isomer has a lower boiling point than an unbranched isomer because there are fewer points of contact between the molecules, which means fewer van der Waals forces.

78

What are short chain alkanes valuable for?

Short chain alkanes are valuable as clean fuels.

79

What is the main constituent of natural gas?

Methane is the main constituent of natural gas.

80

Which alkanes are found in liquefied petroleum gas (LPG)?

Propane and butane are easily liquefied and are commonly known as liquefied petroleum gas.

81

What is liquefied petroleum gas used for?

Liquefied petroleum gas (LPG) is used in BBQs, patio heaters and portable cooking appliances.

82

Which alkane is found in petrol?

Octane is petrol.

83

How is carbon monoxide poisonous?

Carbon monoxide is poisonous because it prevents the haemoglobin in red blood cells from binding with oxygen & the body's tissues become starved of oxygen.

84

Define cracking.

Cracking refers to the breaking down of long-chained saturated hydrocarbons to form a mixture of shorter-chained alkanes and alkenes.

85

What are shorter chain alkanes used for?

Short chain alkanes are used as fuels.

86

What are shorter chain alkenes used for?

Shorter chain alkenes are used in polymer production.

87

What type of catalyst, and at what temperature does cracking now tend to use?

Cracking now uses a zeolite catalyst at ~450oC.

88

Define a catalyst.

A catalyst is a substance that increases the rate of a chemical reaction without being used up in the process.

89

What process can convert unbranched alkanes into branched alkanes?

Unbranched alkanes can be converted into branched alkanes in a process sometimes referred to as isomerisation.

90

What process can convert aliphatic hydrocarbons into cyclic or aromatic hydrocarbons?

Aliphatic hydrocarbons can be converted into cyclic or aromatic hydrocarbons in a process sometimes called reforming.

91

What acronym is used to rate how well a fuel burns?

The research octane number (RON) rates how well a fuel burns.

92

The hydrogen that is produced during reforming is used in what processes?

The hydrogen produced during reforming is used in other chemical processes such as ammonia production and margarine production.

93

In cracking, a mixture of ......... and ........... is ALWAYS formed ?

In cracking, a mixture of alkanes and alkenes is always formed.

94

What percentage of crude oil is used as fuel?

Over 90% of the crude oil produced in the world is used as a source of fuel.

95

What are the features of a good fuel?

A good fuel needs to be readily available, easily transported and inexpensive.

96

Burning hydrocarbons leads to an increase in what?

Burning hydrocarbons leads to an increase in:

  • carbon monoxide
  • carbon dioxide
  • nitrogen oxides
  • sulphur dioxide

97

When is carbon monoxide formed?

Carbon monoxide is a toxic gas formed from incomplete combustion in the internal combustion engine.

98

Why is carbon dioxide bad for the environment?

Carbon dioxide is a major contributor to global warming via the greenhouse effect.

99

Why are nitrogen oxides bad for the environment?

Nitrogen oxides are contributors to acid rain and the destruction of forests.

100

Why is sulphur dioxide bad for the environment?

Sulphur dioxide is a contributor to acid rain.

101

Define a biofuel.

A biofuel is a fuel that is derived from recently living material such as plants or from animal waste.

102

Alkanes will react with halogens  under what conditions?

Halogens react with alkanes in the presence of ultraviolet radiation or at a temperature of ~300oC.

103

What is radical substitution?

Radical substitution is a type of substitution reaction in which a radical replaces a different atom or group of atoms.

104

What are the three steps in a mechanism?

The three steps of a mechanism are initiation, propagation and termination.

105

What is the initiation step of a mechanism?

The initiation is the first step in a radical substituation in which the free radicals are generated by ultraviolet radiation.

106

What is the propagation step of a radical substitution?

Propagation is the two repeated steps in a radical substition that build up the products in a chain reaction.

107

What is the termination step of a mechanism?

The termination step is the step at the end of a radical substitution that build up the products in a chain reaction.

108

When does the human body produce radicals?

The human body produces radicals when fighting infection and burning glucose for energy.

109

Which vitamins are antioxidants? (even though antioxidants are total BS)

Vitamins C and E are antioxidants.

110

Where are we exposed to radicals?

  • cigarette smoke
  • sunbathing
  • general pollution
  • food contamination by herbicides

111

Define an alkene.

Alkenes are unsaturated hydrocarbons with at least one C=C double bond.

112

What is the general formula of aliphatic alkenes with one double bond?

Aliphatic alkenes with one double bond have the general formula CnH2n.

113

TRUE or FALSE

Alkanes are more reactive than alkanes?

FALSE!

Alkenes are more reactive than alkanes.

114

What are the parts of the double bond?

A double bond is made up of a sigma bond and a pi bond.

115

What is the pi bond?

The pi bond is the reactive part of a double bond formed above and below the plane of the bonded atoms by sideways overlap of p-orbitals.

116

How and where does a sigma bond form?

A sigma bond is formed directly between two carbon atoms by the overlap of orbitals.

117

Which part of the double bond fixes the carbon atoms in position?

The pi bond fixes the carbon atoms in position at either end of the double bond.

118

What is the shape of alkene molecules?

Alkene molecules are trigonal planar.

119

What are the bond angles in alkenes?

Alkenes have bond angles of 120o.

120

TRUE or FALSE

Ethene is flat and planar with all the atoms in the same plane.

TRUE!

Ethene is flat and planar with all the atoms in the same plane.

121

What is the most common cyclic alkene?

The most common cyclic alkene is cyclohexene.

122

What is carotene?

Carotene is the orange pigment in carrots, used by the body to make vitamin A.

123

How many double bonds are in carotene?

Carotene has 11 double bonds.

124

What is the average bond enthalpy of a C-C single bond?

The average bond enthalpy of a C-C singe bond is +372kJmol-1.

125

What is the average bond enthalpy of a C=C double bond?

The average bond enthalpy of a C=C double bond is +612kJmol-1.

126

When alkenes react, which part of the double bond breaks?

When alkenes react, the pi bond breaks and the sigma bond remains intact.

127

What conditions are required for an addition of hydrogen to an alkene reaction?

Addition of hydrogen reactions require a mixture of hydrogen gas and a gaseous alkene to pass over a nickel catalyst at 150oC.

128

What temperature is required for the addition of a halogen to an alkene?

Addition of halogens to alkenes happens very rapidly and occurs at room temperature.

129

Halogen halides added to an alkene forms what?

Halogen halides added to an alkene forms a halogenoalkane.

130

Addition of steam to alkenes is one method of preparing what?

Addition of steam to alkenes is one method of preparing alcohols.

131

What conditions are needed for the addition of steam to alkenes?

To make alcohols by adding steam to alkenes, the steam is heated to a high temperature and pressure in the presence of a phosphoric acid catalyst.

132

Define a carbocation.

A carbocation is an organic ion in which a carbon has a positive charge.

133

What are terpenes?

Terpenes are alkenes built from whole numbers of isopropene molecules.

134

A large proportion of all industrially produced ethene is used for what?

A large proportion of industrially produced ethene is polymerised to make plastic.

135

What can ethene be used to produce?

Ethene can be used to make:

  • 1,2-dichloroethane
  • ethane-1,2-diol
  • ethanoic acid

136

What is 1,2-dichlorothane used for?

1,2-dichloroehtane is used as a degreaser and paint remover.

137

What is ethane-1,2-diol used for?

Ethane-1,2-diol is widely used as antifreeze and one of the key materials for making polyesters such as terylene.

138

What is ethanoic acid used for?

Ethanoic acid is used as vinegar and in organic synthesis.

139

Define hyrogenation.

Hydrogenation is the addition of hydrogen molecules across double bonds in an addition reaction.

140

Define a polymer.

A polymer is a long molecular chain built up from monomer units.

141

Define a monomer.

A monomer is a small molecule that combines with many other monomers to form a polymer.

142

Define addition polymerisation.

Addition polymerisation is the process in which unsaturated alkene molecules (monomers) add on to a growing polymer chain one at a time, to form a very long saturated monomer chain (the addition polymer).

143

What conditions does radical polymerisation require?

Radical polymerisation requires temperatures of 200oC and very high pressures.

144

What is the Ziegler-Natta process?

The Ziegler-Natta process is a polymerisation reaction which involves passing an alkene over a specialist catalyst such as Al(C2H5)2Cl or TiCl3 at 60oC, the conversion is low and any unreacted alkene is recycled and passed over the catalyst.

145

Define a repeat unit.

A repeat unit is a specific arrangement of atoms that occurs in the structure over and over again.

146

What are the features of Teflon?

Teflon is resistant to heat, chemically unreactive, other substances don't stick to it as it has low surface friction.

147

What are the properties of orlon and what is it used for?

Orlon is a polymer used as a synthetic fibre. It is resistant to sunlight and atmospheric gases which means it can be used in tent material and sunshades.

148

What is poly(phenylethene) also known as?

Poly(phenylethene) is also known as polystyrene.

149

What are the uses of polystyrene?

Polystyrene is used in foam packaging, insulation, model-making and in the food retail trade.

150

What is poly(propene) used for?

Poly(propene) is used in food packaging for dishwasher-proof containers, fibre in carpets, synthetic ropes and is used in material in some lab equipment.

151

What is poly(ethene) also known as?

Poly(ethene) is also known as polythene.

152

What is the most widely used plastic?

Polythene is the most widely used plastic.

153

Define biodegradeable material.

Biodegradable material is a material that is broken down naturally in the environment by living organisms.

154

Why can't some plastics be recycled?

Much of the plastic waste we create includes additives such as colourants, stabilisers and plasticisers, which often contain poisonous heavy metal ions.

155

Why is the recycling of polyvinyl chloride problematic?

The recycling of polyvinyl chloride (PVC) is problematic because of its high chlorine content.

156

What materials are bioplastics derived from?

Bioplastics are derived from renewable raw materials such as starch, maize, cellulose and lactic acid.