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National 5 Chemistry > Unit 2 - Topic 1 - Hydrocarbons > Flashcards

Unit 2 - Topic 1 - Hydrocarbons Flashcards

1
Q

Name the hydrocarbons obtained from crude oil fractions

A

Candle Wax
Petrol
Diesel
Bottled Gas

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2
Q

Name the different ways you can show the formula of hydrocarbons

A

Molecular Formula
Covalent Bonding
Full Structural Formula
Shortened Structural Formula

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3
Q

Give the prefix for 1

A

Meth-

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4
Q

Give the prefix for 2

A

Eth-

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5
Q

Give the prefix for 3

A

Prop-

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6
Q

Give the prefix for 4

A

But-

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7
Q

Give the prefix for 5

A

Pent-

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8
Q

Give the prefix for 6

A

Hex-

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9
Q

Give the prefix for 7

A

Hept-

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10
Q

Give the prefix for 8

A

Oct-

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11
Q

Give the prefix for 9

A

Non-

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12
Q

Give the prefix for 10

A

Dec-

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13
Q

What is the general formula of the alkanes?

A

CnH2n+2

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14
Q

Do paraffin and methane have similar properties?

A

Yes. The only difference is that methane is a gas and paraffin is a liquid.

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15
Q

Give the state and colour of paraffin

A

Pale-pink liquid

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16
Q

Give the state and colour of methane

A

Colourless gas

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17
Q

Does paraffin give a smell?

A

Strong smell

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18
Q

Does methane give a smell?

A

Odourless

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19
Q

Describe the flammability of paraffin

A

Very flammable

Smokey flame

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20
Q

Describe the flammability of methane

A

Very flammable

Little smoke

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21
Q

Is paraffin soluble in water?

A

No it is immiscible

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22
Q

Is methane soluble in water?

A

No it is immiscible

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23
Q

Give the pH of paraffin

A

Neutral (7)

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24
Q

Give the pH of methane

A

Neutral (7)

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25
Q

Describe the effect of bromine solution on paraffin

A

Remains orange

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26
Q

Describe the effect of bromine solution on methane

A

Remains orange

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27
Q

Describe the effect of bromine solution on alkanes

A

Paraffin and methane do not immediately change the orange colour of bromine solution.

This shows that all alkanes have no immediate effect on bromine solution.

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28
Q

What are paraffin and methane?

A

Hydrocarbons (Alkanes)

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29
Q

Give the word equation for combustion in hydrocarbons

A

Hydrocarbon + Oxygen –> Water + Carbon Dioxide

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30
Q

Name the 3 things alkanes are used in

A

Fuels
Chemicals
Feedstock Chemicals

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31
Q

Give the uses of alkanes in fuels

A

Methane – natural gas

Propane and butane (LPG) – bottled gas

Petrol (gasoline), kerosene (paraffin), diesel

32
Q

Give the uses of alkanes in chemicals

A

Solvents, lubricants, and waxes

33
Q

Give the uses of alkanes in feedstock chemicals

A

Making plastics (polymers), drugs, and pesticides

Making everyday chemicals like ethanol (alcohol), ethanoic acid (acetic acid – vinegar)

34
Q

What is significant about the alkenes?

A

There is a double covalent bond between the carbon atoms

35
Q

Why is ethene the smallest alkene?

A

Because there must be at least 2 carbon atoms in the molecule for the double bond to exist.

36
Q

Give the general formula of alkenes

37
Q

Do alkenes and alkanes have similar structures?

A

Yes except that one of the bonds between two of their carbons is a double bond.

38
Q

Give the state and colour of hexene

A

Colourless liquid

39
Q

Give the state and colour of octene

A

Colourless liquid

40
Q

Does hexene give a smell?

A

Very strong

41
Q

Does octene give a smell?

A

Very strong

42
Q

Describe the flammability of hexene

A

Flammable

Very Smokey flame

43
Q

Describe the flammability of octene

A

Flammable

Very Smokey flame

44
Q

Is hexene soluble in water?

A

No it is immiscible

45
Q

Is octene soluble in water?

A

No it is immiscible

46
Q

Give the pH of hexene

A

Neutral (7)

47
Q

Give the pH of octene

A

Neutral (7)

48
Q

Describe the effect of bromine solution on hexene

A

Turns from orange to colourless

49
Q

Describe the effect of bromine solution on octene

A

Turns from orange to colourless

50
Q

Compare alkanes and alkenes

A

Have strong smells, but alkenes have stronger smells.

Are both very flammable but alkenes produce more smoke when they burn.

Are both insoluble in water – they are immiscible.

Are both neutral substances.

51
Q

Describe alkenes and bromine solution

A

When alkenes are shaken with BROMINE SOLUTION they immediately remove the orange colour, and it turns colourless (decolourises).

This is different to the reaction with alkanes, which do not immediately decolourise bromine solution.

The double bond (C=C) in the alkene molecule is responsible for the rapid decolourisation of bromine solution.

Bromine solution is used to detect the presence of C=C in a molecule, i.e. it can detect alkenes.

52
Q

Describe saturation

A

Carbon based molecules where all the carbon-to-carbon covalent bonds are SINGLE (C-C) are classified as being SATURATED.

53
Q

Describe unsaturation

A

If one or more of the carbon-to-carbon covalent bonds is a DOUBLE (C=C) the molecule is classified as being UNSATURATED.

54
Q

Which hydrocarbon has the highest worldwide production of any organic compound?

55
Q

What is ethene used to make?

A

Plastics (polymers) e.g. polythene, polystyrene, man-made rubber

Ethanol (alcohol) for use as a solvent

Chemicals for making medicines, detergents,

Ethene (ethylene) is used to ripen fruit e.g. bananas. Fruit are picked before they ripen and are stored in conditions to prevent them ripening for their long journey to the UK. Before being sent to the shops, the fruit is exposed to ethene to start ripening. This ensures the fruit is in the best condition for the customer.

56
Q

Describe the physical properties of homologous series

A

The physical properties of the molecules in a homologous series all change as the number of carbon atoms in the molecules increase.

The melting and boiling points, the viscosity of the alkanes, alkenes and cycloalkanes all show an increase going up the series as the number of carbon atoms in their molecules increase.

57
Q

Name 5 different homologous families

A 
Alkanes
Alkenes
Cycloalkanes
Alkanols (Alcohols)
Alkanoic Acids (Carboxylic Acids)
58
Q

How many carbons does the smallest ring contain?

59
Q

Give the general formula of the cycloalkanes

60
Q

Give the state and colour of cyclohexane

A

Colourless liquid

61
Q

Does cyclohexane give a smell?

A

Strong smell

62
Q

Describe the flammability of cyclohexane

A

Very flammable

Smokey flame

63
Q

Is cyclohexane soluble in water?

A

No it is immiscible

64
Q

Give the pH of cyclohexane

A

Neutral (7)

65
Q

Describe the effect of bromine solution on cyclohexane

A

Remains orange

66
Q

Are alkanes saturated or unsaturated?

67
Q

Are alkenes saturated or unsaturated?

A

Unsaturated

68
Q

Are cycloalkanes saturated or unsaturated?

69
Q

What are the different structures of hydrocarbons called?

70
Q

Describe isomers

A

ISOMERS are molecules with the SAME MOLECULAR FORMULA but have DIFFERENT STRUCTURES.

Isomers in the alkane family only occur in molecules with 4 or more carbons.

The more carbons in a molecule the more isomers are possible.

71
Q

How many carbon atoms do branched cycloalkanes have?

72
Q

What can bromine be used for?

A

To detect a C=C in a molecule. This means bromine can detect if a molecule is UNSATURATED.

Alkenes (unsaturated hydrocarbons), rapidly decolourise bromine solution.

The bromine molecule reacts with the C=C, breaking it open and then adding onto the molecule.

73
Q

Describe addition reactions

A

Alkenes can react by addition reactions. The double bond between the carbon atoms C=C breaks open, changing back to a single C-C bond.

The reactant then adds onto the carbon atoms. The production of the reaction is a …alkane

74
Q

Describe the melting/boiling points of hydrocarbons

A

As the molecule gets larger, the number of carbons increase which means that there are greater intermolecular forces of attraction between molecules. This means that more energy is needed to separate it resulting in greater melting/boiling points.

75
Q

What are the 2 functional groups?

A

Hydroxyl Group: O-H

Carboxyl Group: =O -O-H

76
Q

LPG

A

Liquefied Petroleum Gas

National 5 Chemistry (15 decks)

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