Organic Chemistry (C7) Flashcards

1
Q

What is crude oil?

A

A thick mixture extracted from the earth (where sea is or was)
It is made of a mixture of hydrocarbons

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2
Q

How does crude oil form?

A

When sea ceatures (specifically plankton) die and fall to the sea bed they tend to become covered by other layers of sediment.
Over time, pressure and heat may mean they do not rot but instead release the carbon in their bodies.
Over millions of years this creates crude oil.

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3
Q

What are the utilities of crude oil?

A

None it needs to be refined

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4
Q

What does it mean to refine crude oil?

A

Seperate it into useful hydrocarbons

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5
Q

What is the difference between different hydrocarbons in crude oil?

A

They have different molecular chain lengths (they are different sizes). This means they have different properties.

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6
Q

How is crude oil refined?

A

Fractional distillation

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7
Q

What equipment is used for large-scale fractional distillation?

A

Fractional Column

Farctional Tower

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8
Q

Roughly what heat is the bottom of a fractional column?

A

330°C - 350°C

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9
Q

Put simply, what happens in a fractional column?

A

The hydrocarbons vaporise and rise
The column is progressively cooler, higher up the column and thus (depending on boiling point) some of the hydrocarbons will condense again at specific heights.
Here they can be collected.

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10
Q

What organism is most crude oil formed from the fossils of?

A

Plankton

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11
Q

How deep is crude oil usually found?

A

1 or 2 miles

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12
Q

Why do different molecules have different properties?

A

They are different lengths, some chains are longer than others

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13
Q

Answer the 6 marker:
Explain Fractional Distillation
(example answer on back)
Actually write it

A

Fractional distillation is a process by which different hydrocarbons are seperated from crude oil. This process is known as refining and is done because the mixture is not useful but the individual carbons are greatly so.
Different hydrocarbons have different chain lengths, the longer they are the more intermolecular forces and thus the more energy in needed to seperate them. This means the larger molecules have higher boiling points than the small ones.
During fractional distillation the bottom of a fractional column is heated to approx. 350°C and all tht crude oil vaporises. Higher up the column it is cooler and thus some fractions begin to condense. These are each collected as liquids at varying heights. Only the smalest molecules leave as a gas due to their low boiling point.

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14
Q

What do the properties of hydrocarbon depend on?

A

Chain length

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15
Q

Define Volatility

A

The tendancy to become a gas

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16
Q

Define Viscocity

A

Thickness

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17
Q

Which have higher boiling points?

Short or long chain hydrocarbons

A

Long chain hydrocarbons

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18
Q

Why do long chain hydrocarbons have a higher boiling point?

A

They have more intermolecular forces that need to be broken

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19
Q

Which have higher volatility?

Short or long chain hydrocarbons

A

Short chain hydrocarbons

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20
Q

Why do short chain hydrocarbons have a higher volatility?

A

They have fewer intermolecular forces and so they can easily be broken

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21
Q

Which have higher viscocity?

Short or long chain hydrocarbons

A

Long chain hydrocarbons

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22
Q

Why do long chain hydrocarbons have a higher viscocity?

A

They have more atoms in each molecules so they can not flow easily over each other

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23
Q

Which have higher flamability?

Short or long chain hydrocarbons

A

Short chain hydrocarbons

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24
Q

Why do short chain hydrocarbons have a higher flamibility?

A

Less energy is needed

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25
Q

Why do long chain hydrocarbons cause sooty fires?

if they can be burned

A

A lot of energy is needed and therefore combustion is not usually complete
(Some are not flamable because of this)

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26
Q

What are the method to explore the viscocity of a hydrocarbon?

A

Time to Drain

Air Bublle

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27
Q

What happens in a ‘Time to drain’ practical?

A

A syringe is filled with the hydrocarbon
This is held over a beaker
The plunger is pulled out and simultaneously a timer is begun
When all the liquid has pured out it is stopped
Repeat twice more for accuracy
More viscous liquids take longer to clear

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28
Q

What are alkanes?

A

Alkanes are a family of saturated hydrocarbon compounds

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29
Q

What suffix do alkanes have?

A

-ane

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30
Q

What is the general formula of an alkane?

A

CnH2n+2

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31
Q

What are the bonds in alkanes?

A

Alkanes are made up of single covalent bonds between hydrogen and carbon atoms

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32
Q

What is the name of the alkane with the formula CH4

A

Methane

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33
Q

What is the name of the alkane with the formula C4H10

A

Butane

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34
Q

What is the name of the alkane with the formula C2H6

A

Ethane

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35
Q

What is the name of the alkane with the formula C3H8

A

Propane

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36
Q

What is the name of the alkane with the formula C5H12

A

Pentane

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37
Q

Describe the reactivity of alkanes

A

Non reactive as all the outer shells are full (except for combustion)
It is a saturated molecule.

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38
Q

Define a saturated molecule

A

Containing the greatest possible number of hydrogen atoms, without carbon=carbon double or triple bonds

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39
Q

Define Alkenes

A

Unsaturated hydrocarbons

They contain at least 1 double carbon covalent bond C=C

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40
Q

What is the general formula for alkenes?

A

CnH2n

41
Q

Are alkenes reactive?

A

They are reactive as they have a double carbon bond which is less difficult to break

42
Q

Which is the smallest alkane?

A

Methane

43
Q

Which is the smallest alkene?

A

Ethene

44
Q

What is the name of the alkane with the formula C2H4

A

Ethene

45
Q

What is the name of the alkane with the formula C3H6

A

Propene

46
Q

What is the name of the alkane with the formula C4H8

A

Butene

47
Q

What is the name of the alkane with the formula C5H10

A

Pentene

48
Q

What suffix do all alkenes have?

A

-ene

49
Q

What is the general equation for complete combustion?

A

Fuel + Oxygen -> Carbon Dioxide + Water

50
Q

What is the general equation for incomplete combustion?

A

Fuel + Oxygen -> Carbon Monoxide + Water + Carbon

51
Q

What is the difference between complete and incomplete combustion?

A

Complete combustion happens in an oxygen where the entire molecule is broken down and
Incomplete combustion happens when there isn’t enough oxygen where some of the molecule is broken down

52
Q

What type of reaction is combustion?

A

Oxidation

Exothermic

53
Q

What colour is the flame in complete combustion?

A

Blue

54
Q

What colour is the flame in incomplete combustion?

A

Yellow

55
Q

Which type of combustion releases more energy?

A

Complete Combustion

56
Q

What other by product do we see during an incomplete reaction?

A

Black soot forms (carbon)

57
Q

What tests do we do for the products of combustion?

A

Put a flame under a funnel which leads into a U-bend (in an ice bowl with cobalt chloride or anhydrous copper sulphate paper) and the pipe continues into a test tube with limewater in it

58
Q

How do we test for Carbon Dioxide?

A

Limewater turns cloudy and bubbles

59
Q

What are the two ways of testing for water?

A

Cobalt Chloride Paper
Anhydrous Copper Sulphate Paper
Both go from blue to pink in the presence of water

60
Q

Define Cracking

A

Cracking is the breaking down of less useful, large hydrocarbon molecules into smaller, more useful hydrocarbon molecules

61
Q

Which hydrocarbons do we crack?

A

Alkanes

62
Q

What are alkanes cracked into?

A

It is always random but you always get:
Alkenes
And Alkane

63
Q

What are the three ways of cracking?

A

Catalytic
Steam
Thermal

64
Q

Describe catalytic cracking

A
High temperatures (500°)
Zeolite Catalysts
65
Q

Describe steam cracking

A

High temperature

Steam

66
Q

Describe thermal cracking

A
High temperature (700°)
70 atms pressure
67
Q

Which is the most common form of cracking?

A

Catalytic

68
Q

Describe the Addition reactions of alkenes

A

Another molecule (with two atoms) bonds to the alkene double bond. These atoms make bonds with the carbon atoms and the double bond becomes a single.

69
Q

Describe Halogenation of alkenes

A

When you react halogens with alkenes
Halogens are diatomic
The diatomic atoms bond individually to the carbon atoms and the double bond becomes single.

70
Q

Describe the test for alkenes

A

Halogenation of alkenes

In this process the halogen is decolourised

71
Q

What is the product of halegenation?

A
Di - (halogen) - (alkene)
i.e.: dibromoethane
dichloroethane
diiodoethane
(these are the reactions with ethane)
72
Q

Describe Hydrogenation of Alkanes

A

Alkene reacts with Hydrogen (H2) to form an alkane

73
Q

What factors are needed hydrogenation?

A

150*C heat

Nickel Catalyst

74
Q

Describe the reaction with alkanes and water

A

This is reversible
The alkane becomes a molecule with only a single carbon bond
One if the hydrogen atoms bonds to a carbon and the OH molecule also bonds to a carbon atom

75
Q

What is the product of the reaction with alkanes and water?

A

Alchol

76
Q

What is a functional group?

A

A group of atoms whose bonding is the same from molecule to molecule.

77
Q

What are alchols?

A

A homologous series with the functional group -OH

78
Q

Describe an alcohol molecule

A

The carbon atoms are all bonded to hydrogen atoms except for one which bonds to an oxygen and the hydrogen atom

79
Q

What is the general formula for an alcohol?

A

CnH2n+1OH

80
Q

What is the name of the alcohol with the formula CH3OH

A

Methanol

81
Q

What is the name of the alcohol with the formula C2H5OH

A

Ethanol

82
Q

What is the name of the alcohol with the formula C3H7OH

A

Propanol

83
Q

What is the name of the alcohol with the formula C4H9OH

A

Butanol

84
Q

What is the name of the alcohol with the formula C5H11OH

A

Pentanol

85
Q

Define Chemical Feedstock

A

Used to make other chemicals such as adhesives, foams, and solvents

86
Q

What is Methanol used for?

A

Chemical feedstock

87
Q

What is Ethanol used for?

A

Cosmetics

Alcoholic Drinks

88
Q

Describe the boiling points of alcohols

A

Short length have low boiling points

89
Q

Describe the solubility of alcohols

A

Generally soluble but longer chain lengths are less soluble

90
Q

What are the two ways of making alcohols?

A

Fermentation

Catalytic

91
Q

Describe Fermentation to create alcohols

A

Glucose -> Ethanol + Carbon Dioxide

92
Q

Describe the process of using a catalyst to create alcohols

A

Alkene + Water ⇌ Alcohol

93
Q

What is the conditions are used to create alcohols (catalytic)?

A
Phosphoric Acid (H3Po2)
High Pressure Steam
94
Q

How does alcohol react with sodium?

A

(Less vigorously than sodium with water)
Sinks and fizzes, making a pop sound
Becomes and acidic solution

95
Q

Write the equation for propanol burning

A

2C3H7OH + 9O2 -> 6CO2 + 8H2O

96
Q

Write the equation for sodium reacting with water

A

3Na + 3H2O -> 3NaOH +H2

97
Q

Write the equation for sodium reacting with methanol

A

2Na + 2CH3OH -> 2CH3ONa + H2

98
Q

What functional group is propanol in?

A

-OH group