Fuels and Earth Science

Question 1

All fractions from crude oil

Answer 1

Gas
Petrol
Naphtha 
Kerosene 
Diesel oil
Bitumen

Question 2

Uses of gases

Answer 2

Domestic heating

Cooking

Question 3

Uses of petrol

Answer 3

Fuel for cars

Question 4

Uses for naphtha

Answer 4

Dilute heavy crude oil

Question 5

Uses for kerosene

Answer 5

Fuel for aircraft

Question 6

Uses for diesel oil

Answer 6

Fuel for trains and some cars

Question 7

Uses for fuel oil

Answer 7

Fuel for large ships and some power stations

Question 8

Uses for bitumen

Answer 8

Surface roads and roofs

Question 9

Definition of homologous series

Answer 9

Family of molecules that have same general formula and similar chemical properties

Question 10

Why do larger molecules have bigger MP / BP?

Answer 10

There are more intermolecular forces to break so more heat energy is needed to overcome these forces

Question 11

Properties of shorter hydrocarbons

Answer 11

Easy to ignite
Usually gas at room temperature
Lower viscosity (runnier)

Question 12

Properties of longer hydrocarbons

Answer 12

Liquid at room temperature
Harder to ignite
Higher viscosity (thicker)

Question 13

Complete combustion of hydrocarbons

Answer 13

hydrocarbon + oxygen ->

carbon dioxide + water

Question 14

Incomplete combustion of hydrocarbons

Answer 14

hydrocarbon + oxygen(deficient) ->

carbon monoxide + carbon particulates

Question 15

Dangers of carbon monoxide

Answer 15

• can combine with haemoglobin in red blood cells, preventing oxygen circulating properly
• lack of oxygen supply to brain can leas to fainting, coma or death

Question 16

Dangers of carbon particulates

Answer 16

• fine particles of carbon released into atmosphere falls down as soot
• soot reduces air quality, dirtying buildings and worsening respiratory problems

Question 17

Dangers of sulfur dioxide

Answer 17

• made when impurities in fossil fuels are burned
• when mixed with clouds, this makes dilute sulfuric acid and falls as acid rain
• acid rain causes lakes to be more acidic, harming the wildlife
• it also kills trees, damages limestone and stone buildings and makes metal corrode

Question 18

Dangers of nitrogen oxides

Answer 18

• made when nitrogen and oxygen react in the air (energy from combustion in cars)
• contributes to acid rain
• causes photochemical smog, causing breathing difficulties, headaches and tiredness

Question 19

Pros of hydrogen fuel

Answer 19

Clean fuel

Renewable (comes from water)

Question 20

Cons of hydrogen fuel

Answer 20

You need a special, expensive engine

Hydrogen needs to be manufactured and uses energy from another source which has pollutants

Hydrogen is hard to store

Question 21

Definition of cracking

Answer 21

Splitting up of long chain hydrocarbons
Form of thermal decomposition
Used to gain products with more demand from larger, less demand products

Question 22

Cracking method

Answer 22

• vaporised hydrocarbons pass over powdered catalyst
• the hydrocarbons split apart on the surface of the bits of catalyst
• creates a shorter alkane molecule and alkene

Question 23

Phase 1 of atmosphere

Answer 23

• there was no atmosphere
• Earth was just a molten ball that eventually cooled to form a thin crust
• volcanoes continued to erupt, releasing carbon dioxide, steam and methane
• the Earth cooled down further and the water vapour condensed, forming oceans
• there was little oxygen

Question 24

Phase 2 of atmosphere

Answer 24

• lots of early atmosphere dissolved into the ocean
• nitrogen was released into the atmosphere by denitrifying bacteria and ammonia reacting with oxygen
• nitrogen stayed in the atmosphere
• green plants evolved around Earth and removed CO2 as they photosynthesised and formed oxygen
• oxygen levels began to rise and most of CO2 is trapped in fossil fuels and sedimentary rocks

Question 25

Phase 3 of atmosphere

Answer 25

- build up of oxygen killed early organisms that couldn’t handle it - oxygen allowed evolution of more complex organisms that used oxygen - oxygen (O3) created the ozone layer and blocked harmful rays from the sun, allowing more complex organisms to evolve - virtually no CO2 now

Question 26

Ways CO2 levels increased

Answer 26

More combustion for increased energy demand Increased population so increased energy demand Trees cut down for land (plants take CO2 out of atmosphere) Volcano eruptions

Question 27

Greenhouse effect steps

Answer 27

Sun gives out electromagnetic radiation Some EM radiation passed through the atmosphere Shorter wavelengths are absorbed by the Earth, warming it up Some are radiated away by the Earth as infrared Some infrared is absorbed by greenhouse gases - some is reflected back to Earth by greenhouse gases - some is re-emitted back into space - if concentration of greenhouse gases increases further, the greenhouse effect will be stronger and causing more heat radiation to stay and warm up the Earth

Question 28

Ways to estimate past CO2 levels

Answer 28

Fossils Tree rings Gas bubbles in ice sheets