Alkanes

Question 1

Are alkanes saturated or unsaturated?

Answer 1

Saturated

Question 2

What does saturated mean?

Answer 2

Contains no double bonds.

Question 3

What is petroleum?

Answer 3

Crude oil - a mixture of different length hydrocarbons.

Question 4

Is the fractioning column cooler towards the top or bottom?

Answer 4

Cooler towards the top.

Question 5

What length hydrocarbons exit the column at the top?

Answer 5

Shortest.

Question 6

Why do short chain hydrocarbons exit at the top?

Answer 6

They have a lower boiling point.

Question 7

What are the uses for gases?

Answer 7

*liquefied petroleum gas (LPG)
*camping gas

Question 8

What is the use for petrol (gasoline)?

Answer 8

Petrol in vehicles.

Question 9

What is the use for naptha?

Answer 9

Processed to make petrochemicals.

Question 10

What are the uses for kerosene (paraffin)?

Answer 10

*jet fuels
*petrochemicals
*central heating fuel

Question 11

What are the uses for diesel oil?

Answer 11

*diesel fuel
*central heating fuel

Question 12

What is the use for mineral oil?

Answer 12

Lubricating oil.

Question 13

What are the uses for bitumen?

Answer 13

*roofing
*road surfacing

Question 14

What is cracking?

Answer 14

Breaking longer chain alkanes into shorter chain hydrocarbons.

Question 15

What are the conditions in thermal cracking?

Answer 15

*high temperature (1000°C)
*high pressure (70atm)

Question 16

What are the main products of thermal cracking?

Answer 16

Alkenes.

Question 17

What are the products of thermal cracking used for?

Answer 17

Making polymers (plastics).

Question 18

What are the conditions in catalytic cracking?

Answer 18

*high temperature (450°C)
*slight pressure
*zeolite catalyst

Question 19

What are the main products of catalytic cracking?

Answer 19

*aromatic hydrocarbons
*motor fuels

Question 20

What does the catalyst in catalytic cracking enable?

Answer 20

*lower pressure and temperature
*lower cost
*faster reaction

Question 21

Why are alkanes good fuels?

Answer 21

Most burn readily and produce large amounts of energy.

Question 22

What are the products of complete combustion?

Answer 22

Carbon dioxide and water.

Question 23

What are the products of incomplete combustion?

Answer 23

*carbon monoxide (+ water)
*carbon monoxide and carbon dioxide (+ water)
*carbon/soot (+water)

Question 24

How does a catalytic converter remove carbon monoxide?

Answer 24

It reacts it with oxygen to make carbon dioxide (less harmful).

Question 25

Describe the greenhouse effect.

Answer 25

Carbon dioxide (and other greenhouse gases) absorbs infra red radiation from the sun and emit some of it back to earth, making it warmer.

Question 26

How are oxides of nitrogen produced?

Answer 26

High pressures and temperatures in the engine cause nitrogen and oxygen from the air to react together.

Question 27

How do nitrogen oxides increase smog?

Answer 27

Hydrocarbons and nitrogen oxides react in sunlight, forming ground-level ozone (O3), which is a major component of smog.

Question 28

What problems does ground-level ozone cause?

Answer 28

*irritates eyes *aggrevates respiratory problems *causes lung damage

Question 29

How is acid rain formed?

Answer 29

*sulfur reacts with oxygen to form sulfur dioxide when fossil fuels burnt *rises into the atmosphere and combines with water vapor to form sulfuric acid *also happens with nitrogen oxides, which form nitric acid

Question 30

What problems does acid rain cause?

Answer 30

*damages vegetation *kills aquatic life *erodes limestone builidings

Question 31

What does a catalytic converter do?

Answer 31

Reduce the emissions of unburnt hydrocarbons and nitrogen oxides into the atmosphere.

Question 32

What is wet scrubbing?

Answer 32

Using an alkali to neutralise sulfur dioxide in flue gases.

Question 33

How is sulfur dioxide removed from flue gases?

Answer 33

*calcium carbonate/oxide is dissolved in water to from alkaline slurry *spayed on flue gases *sulfur dioxide reacts with calcium compounds and forms calcium sulphite

Question 34

What are the steps involved in free radical substitution?

Answer 34

*initiation *propagation *termination