58-59/64-65 - Crude Oil and Hydrocarbons

Question 1

What are hydrocarbons?

Answer 1

Saturated fuels made only of carbon and hydrogen

Question 2

What allows us to separate mixtures of hydrocarbons?

Answer 2

The different properties of the mixtures, as they are not chemically bonded

Question 3

What are some properties of short molecule hydrocarbons?

Answer 3

Low melting point and boiling point (more volatile)

Gaseous

Not very viscous (gloopy)

More flammable

Question 4

What are the first five alkanes?

Answer 4

Methane, ethane, propane, butane, pentane

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Money Eats People’s Back Pockets

Question 5

What is the formula for the structure of alkanes?

Answer 5

CnH(2n+2)

Question 6

What is crude oil?

Answer 6

A mixture of hydrocarbons

Question 7

What effects can crude oil have on the environment?

Answer 7

Oil spills damage habitats and organisms

Global warming

Acid rain

Global dimming

Question 8

What can be done to reduce sulfur dioxide emissions?

Answer 8

Most of the sulfur can be removed from the fuels before they are burnt (this does require money and uses more energy)

Petrol and diesel can be rep,aced with low sulfur versions

Power stations now have acid gas scrubbers to remove harmful gases before they are released into the atmosphere

Fossil fuel usage could simply be reduced

Question 9

What is cracking?

Answer 9

A thermal decomposition reaction that splits long-chain hydrocarbons

Question 10

What does cracking produce?

Answer 10

A shorter alkane and an alkene

Question 11

How do you crack a hydrocarbon?

Answer 11

1. Heat it into a vapour
2. Pass the vapour over a powdered catalyst

The molecules split apart on the surface of the catalyst

Question 12

What are alkenes?

Answer 12

Unsaturated hydrocarbons (C=C double bond)

Question 13

What are the first four alkenes?

Answer 13

Ethene
Propene
Butene
Pentene

Question 14

What is the general formula for alkenes?

Answer 14

CnH2n - twice as many hydrogens as carbons

Question 15

How can you test for an alkene?

Answer 15

By adding the substance to bromine water - a double bond will open up and form bonds with bromine, turning it from orange to colourless

Question 16

How do you produce ethanol with ethene?

Answer 16

Hydrate it with steam in the presence of a catalyst

Question 17

Why is producing ethanol with ethene not the only method?

Answer 17

Crude oil is non-renewable, so using ethene will become more expensive

Question 18

If not with ethene, how is ethanol produced?

Answer 18

By fermentation

Question 19

What can sugar be converted into? (Word equation)

Answer 19

Sugar -> carbon dioxide + ethanol

Question 20

What are the advantages of producing ethanol from renewable resources?

Answer 20

Lower temperature required

Simpler equipment

Sugar is grown all over the world

Question 21

What are the disadvantages of producing ethanol from renewable resources?

Answer 21

This ethanol is not very concentrated and must be distilled for strength

It needs to be purified

Question 22

What are the steps of fractional distillation of crude oil?

Answer 22

Crude oil vapourised with heat

Different hydrocarbons condense at different temperatures

Leave the column through different tubes

Question 23

What black substance is left after fuels are burned? Why?

Answer 23

Soot (carbon)

Incomplete combustion