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UK GCSE Chemistry > Organic Chemistry (C7) > Flashcards

Organic Chemistry (C7) Flashcards

(98 cards)

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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
Why do long chain hydrocarbons cause sooty fires? | if they can be burned
A lot of energy is needed and therefore combustion is not usually complete (Some are not flamable because of this)
26
What are the method to explore the viscocity of a hydrocarbon?
Time to Drain | Air Bublle
27
What happens in a 'Time to drain' practical?
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
28
What are alkanes?
Alkanes are a family of saturated hydrocarbon compounds
29
What suffix do alkanes have?
-ane
30
What is the general formula of an alkane?
CnH2n+2
31
What are the bonds in alkanes?
Alkanes are made up of single covalent bonds between hydrogen and carbon atoms
32
What is the name of the alkane with the formula CH4
Methane
33
What is the name of the alkane with the formula C4H10
Butane
34
What is the name of the alkane with the formula C2H6
Ethane
35
What is the name of the alkane with the formula C3H8
Propane
36
What is the name of the alkane with the formula C5H12
Pentane
37
Describe the reactivity of alkanes
Non reactive as all the outer shells are full (except for combustion) It is a saturated molecule.
38
Define a saturated molecule
Containing the greatest possible number of hydrogen atoms, without carbon=carbon double or triple bonds
39
Define Alkenes
Unsaturated hydrocarbons | They contain at least 1 double carbon covalent bond C=C
40
What is the general formula for alkenes?
CnH2n
41
Are alkenes reactive?
They are reactive as they have a double carbon bond which is less difficult to break
42
Which is the smallest alkane?
Methane
43
Which is the smallest alkene?
Ethene
44
What is the name of the alkane with the formula C2H4
Ethene
45
What is the name of the alkane with the formula C3H6
Propene
46
What is the name of the alkane with the formula C4H8
Butene
47
What is the name of the alkane with the formula C5H10
Pentene
48
What suffix do all alkenes have?
-ene
49
What is the general equation for complete combustion?
Fuel + Oxygen -> Carbon Dioxide + Water
50
What is the general equation for incomplete combustion?
Fuel + Oxygen -> Carbon Monoxide + Water + Carbon
51
What is the difference between complete and incomplete combustion?
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
What type of reaction is combustion?
Oxidation | Exothermic
53
What colour is the flame in complete combustion?
Blue
54
What colour is the flame in incomplete combustion?
Yellow
55
Which type of combustion releases more energy?
Complete Combustion
56
What other by product do we see during an incomplete reaction?
Black soot forms (carbon)
57
What tests do we do for the products of combustion?
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
How do we test for Carbon Dioxide?
Limewater turns cloudy and bubbles
59
What are the two ways of testing for water?
Cobalt Chloride Paper Anhydrous Copper Sulphate Paper Both go from blue to pink in the presence of water
60
Define Cracking
Cracking is the breaking down of less useful, large hydrocarbon molecules into smaller, more useful hydrocarbon molecules
61
Which hydrocarbons do we crack?
Alkanes
62
What are alkanes cracked into?
It is always random but you always get: Alkenes And Alkane
63
What are the three ways of cracking?
Catalytic Steam Thermal
64
Describe catalytic cracking
``` High temperatures (500°) Zeolite Catalysts ```
65
Describe steam cracking
High temperature | Steam
66
Describe thermal cracking
``` High temperature (700°) 70 atms pressure ```
67
Which is the most common form of cracking?
Catalytic
68
Describe the Addition reactions of alkenes
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
Describe Halogenation of alkenes
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
Describe the test for alkenes
Halogenation of alkenes | In this process the halogen is decolourised
71
What is the product of halegenation?
``` Di - (halogen) - (alkene) i.e.: dibromoethane dichloroethane diiodoethane (these are the reactions with ethane) ```
72
Describe Hydrogenation of Alkanes
Alkene reacts with Hydrogen (H2) to form an alkane
73
What factors are needed hydrogenation?
150*C heat | Nickel Catalyst
74
Describe the reaction with alkanes and water
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
What is the product of the reaction with alkanes and water?
Alchol
76
What is a functional group?
A group of atoms whose bonding is the same from molecule to molecule.
77
What are alchols?
A homologous series with the functional group -OH
78
Describe an alcohol molecule
The carbon atoms are all bonded to hydrogen atoms except for one which bonds to an oxygen and the hydrogen atom
79
What is the general formula for an alcohol?
CnH2n+1OH
80
What is the name of the alcohol with the formula CH3OH
Methanol
81
What is the name of the alcohol with the formula C2H5OH
Ethanol
82
What is the name of the alcohol with the formula C3H7OH
Propanol
83
What is the name of the alcohol with the formula C4H9OH
Butanol
84
What is the name of the alcohol with the formula C5H11OH
Pentanol
85
Define Chemical Feedstock
Used to make other chemicals such as adhesives, foams, and solvents
86
What is Methanol used for?
Chemical feedstock
87
What is Ethanol used for?
Cosmetics | Alcoholic Drinks
88
Describe the boiling points of alcohols
Short length have low boiling points
89
Describe the solubility of alcohols
Generally soluble but longer chain lengths are less soluble
90
What are the two ways of making alcohols?
Fermentation | Catalytic
91
Describe Fermentation to create alcohols
Glucose -> Ethanol + Carbon Dioxide
92
Describe the process of using a catalyst to create alcohols
Alkene + Water ⇌ Alcohol
93
What is the conditions are used to create alcohols (catalytic)?
``` Phosphoric Acid (H3Po2) High Pressure Steam ```
94
How does alcohol react with sodium?
(Less vigorously than sodium with water) Sinks and fizzes, making a pop sound Becomes and acidic solution
95
Write the equation for propanol burning
2C3H7OH + 9O2 -> 6CO2 + 8H2O
96
Write the equation for sodium reacting with water
3Na + 3H2O -> 3NaOH +H2
97
Write the equation for sodium reacting with methanol
2Na + 2CH3OH -> 2CH3ONa + H2
98
What functional group is propanol in?
-OH group

UK GCSE Chemistry (9 decks)

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