Fuels

Question 1

Why do hydrocarbons have a higher viscosity?

Answer 1

Because they have longer chains

Question 2

What does high viscosity mean for hydrocarbons?

Answer 2

They are thicker and flow less easily

Question 3

Why do hydrocarbons have higher boiling points?

Answer 3

Because they have longer chains

Question 4

Why are hydrocarbons less flammable?

Answer 4

Because they have longer chains

Question 5

What are produces when vaporised hydrocarbons are mixed with steam in a high temperature environment?

Answer 5

Alkanes and alkenes

Question 6

What is produced when a vaporised hydrocarbon is passed over a hot catalyst?

Answer 6

Alkane and alkene

Question 7

What type of chemical reaction is invoked with cracking?

Answer 7

Thermal decomposition reactions

Question 8

what is crude oil made of?

Answer 8

a complex mixture of lots of hydrocarbon

Question 9

what are hydrocarbons?

Answer 9

compounds that contain hydrogen and carbon atoms only

Question 10

what does crude oil produce?

Answer 10

fuels, such as petrol and diesel

Question 11

how is crude oil formed?

Answer 11

over millions of years, from the effects of high pressures and temperatures on the remains of plants and animals

Question 12

what does crude oil contain?

Answer 12

molecules with rings of carbon atoms

Question 13

how much of crude oil is there?

Answer 13

a finite resource

Question 14

where can crude oil be found?

Answer 14

under the sea and ground

Question 15

what does finite mean?

Answer 15

it will run out

Question 16

what are reasons for separating crude oil?

Answer 16

Unseparated crude oil isn’t very useful
separated products are very useful

Question 17

what are uses of refinery gas?

Answer 17

heating and cooking

Question 18

what are uses of kerosene?

Answer 18

aircraft fuel

Question 19

what are the uses of diesel oil?

Answer 19

cars and trains

Question 20

what are the differences between hydrocarbons in each fraction?

Answer 20

boiling points
ease of ignition
viscosity
the number of hydrogen and carbon atoms their molecules have

Question 21

what is viscosity?

Answer 21

how thick and sticky a substance is

Question 22

what are the properties of hydrocarbons tapped from the top of the fractionating column?

Answer 22

low boiling point
highly volatile
easily ignited
shorter carbon chains

Question 23

what happens when fuel undergoes complete combustion?

Answer 23

energy is given out

Question 24

what is the balanced equation for complete combustion of ethane?

Answer 24

2c2H6 + 7o2 -> 4co2 + 6H2o

Question 25

when does incomplete combustion occur?

Answer 25

when there is an insufficient supply of oxygen

Question 26

how to ensure complete combustion occurs?

Answer 26

the reaction should be carried out with excess oxygen

Question 27

what are the products of incomplete combustion?

Answer 27

carbon particulates carbon monoxide water

Question 28

what are the problems with carbon monoxide?

Answer 28

toxic gas colourless and odourless, can cause death

Question 29

how does carbon monoxide cause death?

Answer 29

be preventing the red blood cells from carrying oxygen around the body

Question 30

what are the problems with incomplete combustion?

Answer 30

produces carbon monoxide which is toxic and fatal produces carbon particulates which cause global dimming and respiratory problems

Question 31

what happens when fuels are burned?

Answer 31

the sulfur impurities in the hydrocarbons, react with oxygen to form sulfur dioxide

Question 32

how is acid rain produced?

Answer 32

sulfur dioxide evaporates into the air. it reacts with in the clouds to form sulfuric acid. This is acid rain

Question 33

what are the problems caused by acid rain?

Answer 33

corrodes buildings - limestone kills vegetation lowers the pH of large bodies of water - killing wildlife

Question 34

how oxides of nitrogen are produced from car engines?

Answer 34

the high temperatures and pressure of a car engine causes nitrogen and oxygen from thw air to react together

Question 35

what are the problems associated with oxides of nitrogen?

Answer 35

pollutants produce acid rain with similar effects as So2 cause respriatory problems

Question 36

what are advantages of using hydrogen in cars?

Answer 36

releases more energy renewable source, can be extracted from water

Question 37

disadvantages of using hydrogen in cars?

Answer 37

expensive, produced with electrolysis difficult and dangerous to store

Question 38

what is methane?

Answer 38

non-renewable fossil fuel found in natural gas

Question 39

what is cracking?

Answer 39

breaking down large hydrocarbons into smaller more useful ones

Question 40

what are the properties of the main fractions of crude oil?

Answer 40

some properties of hydrocarbons depend on the size of their molecules