Unit 2 - Topic 1 - Hydrocarbons Flashcards
(76 cards)
1
Q
Name the hydrocarbons obtained from crude oil fractions
A
Candle Wax
Petrol
Diesel
Bottled Gas
2
Q
Name the different ways you can show the formula of hydrocarbons
A
Molecular Formula
Covalent Bonding
Full Structural Formula
Shortened Structural Formula
3
Q
Give the prefix for 1
A
Meth-
4
Q
Give the prefix for 2
A
Eth-
5
Q
Give the prefix for 3
A
Prop-
6
Q
Give the prefix for 4
A
But-
7
Q
Give the prefix for 5
A
Pent-
8
Q
Give the prefix for 6
A
Hex-
9
Q
Give the prefix for 7
A
Hept-
10
Q
Give the prefix for 8
A
Oct-
11
Q
Give the prefix for 9
A
Non-
12
Q
Give the prefix for 10
A
Dec-
13
Q
What is the general formula of the alkanes?
A
CnH2n+2
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.
15
Q
Give the state and colour of paraffin
A
Pale-pink liquid
16
Q
Give the state and colour of methane
A
Colourless gas
17
Q
Does paraffin give a smell?
A
Strong smell
18
Q
Does methane give a smell?
A
Odourless
19
Q
Describe the flammability of paraffin
A
Very flammable
Smokey flame
20
Q
Describe the flammability of methane
A
Very flammable
Little smoke
21
Q
Is paraffin soluble in water?
A
No it is immiscible
22
Q
Is methane soluble in water?
A
No it is immiscible
23
Q
Give the pH of paraffin
A
Neutral (7)
24
Q
Give the pH of methane
A
Neutral (7)
25
Describe the effect of bromine solution on paraffin
Remains orange
26
Describe the effect of bromine solution on methane
Remains orange
27
Describe the effect of bromine solution on alkanes
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.
28
What are paraffin and methane?
Hydrocarbons (Alkanes)
29
Give the word equation for combustion in hydrocarbons
Hydrocarbon + Oxygen --> Water + Carbon Dioxide
30
Name the 3 things alkanes are used in
Fuels
Chemicals
Feedstock Chemicals
31
Give the uses of alkanes in fuels
Methane – natural gas
Propane and butane (LPG) – bottled gas
Petrol (gasoline), kerosene (paraffin), diesel
32
Give the uses of alkanes in chemicals
Solvents, lubricants, and waxes
33
Give the uses of alkanes in feedstock chemicals
Making plastics (polymers), drugs, and pesticides
Making everyday chemicals like ethanol (alcohol), ethanoic acid (acetic acid – vinegar)
34
What is significant about the alkenes?
There is a double covalent bond between the carbon atoms
35
Why is ethene the smallest alkene?
Because there must be at least 2 carbon atoms in the molecule for the double bond to exist.
36
Give the general formula of alkenes
CnH2n
37
Do alkenes and alkanes have similar structures?
Yes except that one of the bonds between two of their carbons is a double bond.
38
Give the state and colour of hexene
Colourless liquid
39
Give the state and colour of octene
Colourless liquid
40
Does hexene give a smell?
Very strong
41
Does octene give a smell?
Very strong
42
Describe the flammability of hexene
Flammable
| Very Smokey flame
43
Describe the flammability of octene
Flammable
| Very Smokey flame
44
Is hexene soluble in water?
No it is immiscible
45
Is octene soluble in water?
No it is immiscible
46
Give the pH of hexene
Neutral (7)
47
Give the pH of octene
Neutral (7)
48
Describe the effect of bromine solution on hexene
Turns from orange to colourless
49
Describe the effect of bromine solution on octene
Turns from orange to colourless
50
Compare alkanes and alkenes
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
Describe alkenes and bromine solution
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
Describe saturation
Carbon based molecules where all the carbon-to-carbon covalent bonds are SINGLE (C-C) are classified as being SATURATED.
53
Describe unsaturation
If one or more of the carbon-to-carbon covalent bonds is a DOUBLE (C=C) the molecule is classified as being UNSATURATED.
54
Which hydrocarbon has the highest worldwide production of any organic compound?
Ethene
55
What is ethene used to make?
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
Describe the physical properties of homologous series
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
Name 5 different homologous families
```
Alkanes
Alkenes
Cycloalkanes
Alkanols (Alcohols)
Alkanoic Acids (Carboxylic Acids)
```
58
How many carbons does the smallest ring contain?
3
59
Give the general formula of the cycloalkanes
CnH2n
60
Give the state and colour of cyclohexane
Colourless liquid
61
Does cyclohexane give a smell?
Strong smell
62
Describe the flammability of cyclohexane
Very flammable
| Smokey flame
63
Is cyclohexane soluble in water?
No it is immiscible
64
Give the pH of cyclohexane
Neutral (7)
65
Describe the effect of bromine solution on cyclohexane
Remains orange
66
Are alkanes saturated or unsaturated?
Saturated
67
Are alkenes saturated or unsaturated?
Unsaturated
68
Are cycloalkanes saturated or unsaturated?
Saturated
69
What are the different structures of hydrocarbons called?
Isomers
70
Describe isomers
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
How many carbon atoms do branched cycloalkanes have?
6
72
What can bromine be used for?
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
Describe addition reactions
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
Describe the melting/boiling points of hydrocarbons
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
What are the 2 functional groups?
Hydroxyl Group: O-H
| Carboxyl Group: =O -O-H
76
LPG
Liquefied Petroleum Gas
