Organic chemistry Flashcards

1
Q

What are the only elements hydrocarbons contain?

A

Hydrogen and carbon atoms

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2
Q

What is a hydrocarbon?

A

Any compound that is formed from carbon and hydrogen atoms only.

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3
Q

What type of bonds do all alkanes have?

A

C-C single bonds

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4
Q

What are alkanes?

A

The simplest type of hydrocarbon you can get.
A homologous series.
Saturated compounds.

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5
Q

What is the general formula of alkanes?

A

CnH2n+2

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6
Q

What is a homologous series?

A

A group of organic compounds that react in a similar way.
These groups contain similar compounds with many properties in common.

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7
Q

What are saturated compounds?

A

Where each carbon atom in a molecule forms four single covalent bonds.

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8
Q

What are the first four alkanes?

A

Methane
Ethane
Propane
Butane

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9
Q

What is the mnemonic for remembering the names of alkanes?

A
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10
Q

What is a displayed formula?

A

A drawing showing all the atoms and bonds in a molecule.

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11
Q

Draw the displayed formula of methane (CH4)

A
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12
Q

Draw the displayed formula of ethane (C2H6)

A
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13
Q

Draw the displayed formula of propane (C3H8)

A
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14
Q

Draw the displayed formula of butane (C4H10)

A
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15
Q

The shorter the carbon chain…

A

. The more runny a hydrocarbon is. It will be less viscous
. The more volatile the hydrocarbon
. The more flammable the hydrocarbon is

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16
Q

What do the properties of hydrocarbon affect?

A

How they’re used for fuels.
E.g. short chain hydrocarbons with lower boiling points are used as ‘bottled gasses’- stored under pressure as liquids in bottles.

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17
Q

When does complete combustion ocuur?

A

When there’s plenty of oxygen.

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18
Q

What does the complete combustion of any hydrocarbon in oxygen release?

A

Lots of energy

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19
Q

What are the only waste products of complete combustion?

A

Carbon dioxide and water vapor.

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20
Q

What is the word equation for the complete combustion of any hydrocarbon?

A

Hydrocarbon + oxygen —> carbon dioxide + water (+energy)

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21
Q

What happens to both carbon and hydrogen in the complete combustion of hydrocarbons?

A

Both carbon and hydrogen are oxidised.

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22
Q

What can hydrocarbons be used as?

A

Fuels, due to the amount of energy released when they combust completely.

23
Q

Write a balanced equation for the complete combustion of methane (CH4)?

A

CH4 + 2CO —> CO2 + 2H2O

24
Q

What piece of equipment can be used to separate the different hydrocarbons in crude oil?

A

Fractional distillation

25
Q

Is crude oil a fossil fuel/

A

YES

26
Q

How is crude oil formed?

A

It’s formed from the remains of plants and animals, mainly plankton, that died millions of years ago and were buried in the mud. Over millions of years, with high temperature and pressure, the remains turn to crude oil, which can be drilled up from the rocks where it’s found.

27
Q

What are non-renewable fuels?

A

Fuels that take so long to make that they’re being used up much faster than they’re being formed. E.g. coal, oil, gas.

28
Q

What is crude oil?

A

A mixture of lots of different hydrocarbons, most of which are alkanes.

28
Q

What are finite resources?

A

Resources that will one day run out.

29
Q

How is crude oil separated into different hydrocarbons fractions using fractional distillation?

A

1) Crude oil heated until most of it has turned into a gas. The gases enter a fractionating column (and the liquid bit is drained off).
2) In the column there’s a temperature gradient (hot at the bottom and gets cooler as you go up).
3) Longer hydrocarbons = higher boiling points. They condense back into liquids and drain out of the column early on, when they’re near the bottom. Shorter hydrocarbons = lower boiling points. They condense and drain out later on, near the top of the column where it’s cooler.
4) You end up with the crude oil mixture separated out into different fractions. Each fraction contains a hydrocarbon where all molecules contain a similar number of carbon atoms, so have a similar boiling point.

30
Q

Draw a rough diagram of a crude oil fractionating column

A
31
Q

What materials are produced from the fractional distillation of crude oil? (In order of the decreasing approx. number of carbons in that hydrocarbon)

A

Bitumen
Heavy fuel oil
Diesel oil
Kerosene
Petrol
Liquified Petroleum Gas (LPG)

32
Q

What can heavy fuel oil be used for?

A

This can be heating oil, fuel oil or lubricating oil.

33
Q

What can diesel oil be used for?

A

Used as fuel for larger vehicles e.g. lorries and some cars

34
Q

What can kerosene be used for?

A

Burning domestically for light/cooking.
Fuel for jet engines.
Solvent for greases and insecticides.

35
Q

What can petrol be used for?

A

Fuel vehicles e.g. cars.
Heat buildings
Produce electricity

36
Q

What can LPG be used for?

A

In heating and cooking appliances.
In vehicles
Industrial applications

37
Q

What are some of the uses for crude oil in general?

A

. Fuel for most modern transport
. Petrochemical industry- some hydrocarbons are used as feedstock to make new compounds for things like polymers, solvents, lubricants, detergents

38
Q

What are all the products you get from crude oil an example of?

A

Examples of organic compounds.

39
Q

What are organic compounds?

A

Compounds containing carbon atoms.

40
Q

Why can you get such a large variety of products from crude oil?

A

Because carbon atoms can bond together to form different homologous series.

41
Q

What does cracking mean?

A

Splitting up long-chain hydrocarbons.

42
Q

Why are short-chain hydrocarbons in high demand?

A

They are flammable so make good fuels.

43
Q

What do long-chain hydrocarbons form?

A

Thick gloopy liquids e.g. tar which aren’t that useful.

44
Q

What happens to a lot of the longer alkane molecules produces from the fractional distillation of crude oil?

A

They are turned into smaller, more useful molecules by a process called cracking.

45
Q

What types of hydrocarbons are produced from cracking?

A

Alkanes and alkenes

46
Q

What are alkenes used for?

A

Can be used as a starting position when making lots of other compounds and can be used to make polymers.

47
Q

What can some of the products of cracking be used for?

A

They are useful as fuels e.g. petrol for cars and paraffin for jet fuel.

48
Q

What type of reaction is cracking?

A

Thermal decomposition reaction.

49
Q

What is thermal decomposition?

A

Breaking molecules down by heating them.

50
Q

How do we carry out catalytic cracking on long-chain hydrocarbons?

A

1) Heat the long-chain hydrocarbons to vaporise them.
2) Then the vapour is passed over a hot powdered aluminium oxide catalyst.
3) The long-chain molecules them split apart on the surface of the specks of catalyst.

51
Q

How do we carry out steam cracking on long-chain hydrocarbons?

A

1) Vaporise them.
2) Mix them with steam.
3) Heat them to a very high temperature.

52
Q
A