Topic 8 Fuels And Earth Science (complete)

Question 1

Define what a hydrocarbon is

Answer 1

Compounds that contain only carbon and hydrogen

Question 2

What is crude oil

Answer 2

Mixture of hydrocarbons with carbon atoms in chains

Question 3

How is crude oil useful

Answer 3

Important source of useful substances as fuels

Question 4

What does a finite resource mean

Answer 4

You will eventually run out of that resource

Question 5

How is crude oil separated into its fractions by fractional distillation
(Size of molecules and boiling points)

Answer 5

Hydrocarbons with longer chains have higher boiling points so they turn back into liquids and drain out at the bottom
Hydrocarbons with smaller chains have lower boiling points so they get turned into gases and rise to the top and cool later

Question 6

Give the uses for each
Gases
Petrol
Kerosene
Diesel Oil
Fuel Oil
Bitumen

Answer 6

Gases:domestic heating and cooking
Petrol:fuel for cars
Kerosene:fuel for aircraft
Diesel oil: some cars and trains
Fuel oil:large ships and power stations
Bitumen:road surfaces and roofs

Question 7

How are the different fractions in hydrocarbons different

Answer 7

Number of carbon and hydrogen atoms in molecules
Boiling points
Ease of ignition
Viscosity

Question 8

What is a homologous series

Answer 8

Compounds that have ;
Same general formula
Differ to each other by CH2
Gradual change in physical properties
Similar chemical properties

Question 9

What is formula for complete combustion

Answer 9

Hyrdrocarbon + oxygen -> carbon dioxide + water

Question 10

What do incomplete and complete combustion both produce(not a molecule)

Answer 10

Both give out energy

Question 11

What is the difference between complete and incomplete combustion in terms of oxygen

Answer 11

Incomplete combustion takes place under limited supply of oxygen

Question 12

What does viscosity mean

Answer 12

How easily a substance flows
High viscosity means thick

Question 13

Why does incomplete combustion form carbon and carbon monoxide

Answer 13

Because there is less oxygen to make carbon dioxide

Question 14

Why is carbon monoxide bad

Answer 14

Is a toxic gas as it binds with red blood cells to stop oxygen binding to them and can be fatal

Question 15

What is soot

Answer 15

Black dust that reduces air quality ,makes surfaces dirty and cause respiratory problems

Question 16

Sulfur dioxide comes from sulfur impurities in fossil fuels and what does it do

Answer 16

Dissolved in rain water to form sulfuric acid which causes acid rain

Question 17

Why is acid rain bad

Answer 17

Lakes to be acidic plants and animals die
Damaged buildings trees and metals corrode

Question 18

What are nitrogen oxides and how are they made

Answer 18

Reaction between nitrogen and oxygen when energy is released by combustion reactions and is a harmful pollutant

Question 19

What are the advantages of using hydrogen gas to power vehicles

Answer 19

Hydrogen is a clean fuel
Only waste product is water
Renewable energy resource

Question 20

What are the disadvantages of using hydrogen gas to power vehicles

Answer 20

You need a special expensive engine
Hydrogen gas still needs to be manufactured which still uses energy from burning fossil fuels
Hard to store

Question 21

How are petrol kerosene and diesel oil obtained

Answer 21

Non renewable and obtained from crude oil

Question 22

How is methane obtained

Answer 22

Non renewable fossil fuel found in natural gas

Question 23

What is cracking

Answer 23

Breaking down of larger saturated hydrocarbon molecules (alkanes) into smaller more useful unsaturated ones (alkenes)

Question 24

Why is cracking important

Answer 24

Longer chain hydrocarbons are usually less useful than the shorter hydrocarbon chains so cracking makes more of the shorter more useful ones

Question 25

What type of reaction is cracking

Answer 25

Thermal decomposition reaction
Breaking down one substance into at least 2 new ones when heated
Breaking covalent bonds so needs lots of energy

Question 26

Longer chain hydrocarbon molecule——>?

Answer 26

Shorter chain alkane + Alkene

Question 27

Where was the earths early atmosphere produced from

Answer 27

Volcanic activity

Question 28

What was the earths early atmosphere like due to high volcanic activity

Answer 28

Little oxygen
Large amounts of carbon dioxide
Water vapour
Small amounts of other gases

Question 29

How were oceans made in the earths early atmosphere

Answer 29

Water vapour condensed into water and formed the oceans

Question 30

How did amount of carbon dioxide in atmosphere decrease in earths early atmosphere

Answer 30

Carbon dioxide dissolved into the oceans

Question 31

What do the growth of plants do to carbon dioxide and oxygen levels in the earths early atmosphere

Answer 31

Plants produced Oxygen and removed carbon dioxide from the atmosphere

Question 32

What is the test for oxygen

Answer 32

Check if the gas will relight a glowing splint

Question 33

What is the greenhouse effect

Answer 33

Where the gases in the atmosphere absorb more heat radiation and let less pass back into space causing earth to warm up

Question 34

What is the correlation between change in atmospheric carbon dioxide concentration and consumption of fossil fuels and temperature change

Answer 34

Human population is growing rapidly so that means there is higher demand for energy which means burning more fossil fuels admitting more carbon dioxide into atmosphere meaning higher temperatures due to greenhouse effect

Question 35

Why is historical data about climate change less accurate than current

Answer 35

Because less measurements were taken in fewer locations with less specialised equipment we have now

Question 36

What is the composition of gases in todays atmosphere

Answer 36

78% nitrogen
21% oxygen
1% of other gases mainly carbon dioxide ,noble gases and water vapour

Question 37

What effects does climate change have on the climate

Answer 37

Avenges temperature of earth increases
Big changes in weather like forest fires ,flooding