Topic 8 - Fuels and Earth Science

Question 1

Hydocarbons are

Answer 1

Compounds that only contain carbon and hydrogen

Question 2

Crude oil is

Answer 2

A complex mixture of hydrocarbons.
The hydrocarbons have their carbons arranged in chains or rings
Important source of substances called a feedstock for petrochemical industry)
A finite resource

Question 3

Crude oil is seperated by

Answer 3

Fractional distillation

Question 4

Fractional distillation is

Answer 4

When the oil is heated to a gas then enter the fractionating column where there is a temp gradient.
It is hot at the bottom and cooler at the top.
The longer hydrocarbons have higher boiling points, so condensate at the bottom.
Creates 6 different fractions

Question 5

The 6 fractions in fractional distillation(top to bottom)

Answer 5

Gases
Petrol
Kerosene
Diesel oil
Fuel oil
Bitumen

Question 6

Use of gases fraction

Answer 6

Used in domestic heating and cooking

Question 7

Petrol fraction use

Answer 7

Fuel for cars

Question 8

Kerosene fraction use

Answer 8

Fuel in aircraft

Question 9

Diesel oil fraction use

Answer 9

Fuel in some cars, larger vehicles and trains

Question 10

Fuel oil fraction use

Answer 10

Fuel for large ships and soem power stations

Question 11

Bitumen fraction use

Answer 11

Used to surface roads and roofs

Question 12

The lower the fraction in fractional distillation,

Answer 12

The number of hydrogen and carbon atoms in molecules increase
Boiling point increases
Ease of ignition decreases
Viscocity increases

Question 13

The hydrocarbons in crude oil are mainly

Answer 13

part of the alkane homologous series

Question 14

A homologous series is

Answer 14

A family of molecules which have the same general formula and share similar chemical properties.
They differ from neighbouring compounds by a CH2
Gradual variation in physical properties

Question 15

two homologous series’ of hydrocarbons

Answer 15

Alkanes and alkenes

Question 16

Hydrocarbons are good fuels because

Answer 16

The combustion reactions give out lots of energy. Very exothermic.

Question 17

When hydrocarbons are burned in plenty of oxygen

Answer 17

Complete combustion occurs, and the only products formed are carbon dioxide and water.
Release lots of energy

Question 18

When hydrocarbons are burned in insufficient oxygen

Answer 18

Incomplete combustion occurs.
This produces carbon dioxide and water, but also carbon and carbon monoxide(CO)

Question 19

Why is carbon monoxide bad

Answer 19

It is toxic as it combines with red blood cells and stops blood carryign oxygen.
This can lead to death

Question 20

Why is carbon bad

Answer 20

Tiny particles of it are relased into the atomsphere, and when they fall they form balck dust called soot.
Reduces air quality and makes builidings look dirty

Question 21

Incomplete combustion occurs in

Answer 21

Some appliances that use carbon compounds as fuels

Question 22

Sulfur dioxide can be produced by fossil fuels if

Answer 22

They contain sulfur impurities

Question 23

Sulfur dioxide is bad because

Answer 23

It mixes with the clouds and forms dilute sulfuric acid. This falls as aicd rain

Question 24

Acid rain is bad because

Answer 24

It causes lakes to become acidic, and many plants and animals die
Kills trees, damages limestone buildings and stone statues, and causes metal corrosion

Question 25

Nitrogen oxides are produced by

Answer 25

Reactions between nitrogen and oxygen in the air caused by the energy released in combustion(eg by car engines)

Question 26

Nitrogen oxides are bad because

Answer 26

They are harmful ppolutants that can contribute to acid rain, and can cause a photochemical smog, which leads to breathing difficulties

Question 27

Advanatges of using hydrogen to fuel cars

Answer 27

Very clean fuel Only waste product is water Renewable resource as it is obtained by the electrolysis of water

Question 28

Disadvantages of using hydrogen to fuel cars

Answer 28

Expensive engine Expensive to obtain pure hydrogen Hydrogen is hard to store

Question 29

Non-renewable fossils fuels from crude oil

Answer 29

Petrol Kerosene Diesel oil

Question 30

Non-renewable fossil fuel found in natural gas

Answer 30

Methane

Question 31

Cracking is

Answer 31

The splitting up of long, saturated hydrocarbons(alkanes) into smaller hydrocarbons. Some of the smaller ones are unsaturated(alkenes)

Question 32

Cracking is done by

Answer 32

Heating up a larger hydrocarbon, and breaking the strong covalent bonds.

Question 33

Cracking process

Answer 33

Vaporised hydrocarbons are passed over powdered catalysts at about 400*C-700*C. Pressure of 70atm. Aluminium oxide is the catalyst used, and the large lakanes split apart in the conditions.

Question 34

Cracking is necessary because

Answer 34

Because the demand for petrol and diesel is much higher than fuel oil and bitumen, so they are broken down to make more of the in-demand alkanes. It also can produce and alkene used to make polymers.

Question 35

The eartghs early atomsphere was formed by

Answer 35

Volcanoes releasing gases(carbon dioxide, steam, methane and ammonia).

Question 36

Early atmosphere contained

Answer 36

Little or no oxygen Large amount of CO2 Water vapour Small amounts of other gases(ammonia, methane)

Question 37

Oceans formed by

Answer 37

Water vapour condensed into large masses of water

Question 38

The amount of CO2 in the atomsphere first decreased by

Answer 38

CO2 dissolving into the oceans

Question 39

How was nitrogen gas put in the atmosphere

Answer 39

Ammonia reacting with oxygen, released by denitrifying bacteria. N2 isnt reactive so increased in amount

Question 40

How did oxygen get into the ealry atmosphere

Answer 40

Green plants evolved and photosynthesised. Slowly removed CO2 and produced o2

Question 41

Oxygen in the ealry atmosphere allowed`

Answer 41

Complex organisms to evolve Created the ozone layer

Question 42

Chemical test for oxygen

Answer 42

If the gas relights a glowing splint it is oxygen

Question 43

The greenhouse effect process

Answer 43

EM radiation from sun gets filtered through the atmosphere and some gets in. Short wavelengths are absorbed which warms the planet The earth radiates some heat radiation that has been absorbed from longer wavelength IR radiation Some of this is absorbed by greenhosue gases The gases radiate some of it back to earth The absorbtion and re-emission of this IR is what keep the earth warm

Question 44

Greenhouse gases are

Answer 44

The gases in the atmosphere that can absorb and reflect heat radiation. Carbon dioxide, steam, methane etc

Question 45

Human activity is causing

Answer 45

CO2 concentration to increase

Question 46

Temperature change is correlated to

Answer 46

the increase in CO2 and methane concentration in recent decades

Question 47

There are uncertainties in historical data because

Answer 47

The measurements were less accurate and sometimes non-existent. Some of it is predicted using analysis of fossils and gas bubbles

Question 48

Composition of todays atmosphere

Answer 48

Nitrogen mainly 20% oxygen Less than 0.1% of CO2 Tiny amounts of methane

Question 49

CO2 concentration has increased due to

Answer 49

Burning of fossils fuels to meet higher energy demands. deforestation to house people and grow food.

Question 50

Methane concentration increase due to

Answer 50

Higher amount of livestock farmed. They produce methane in digestive process.

Question 51

CO2 and methane increase is bad because

Answer 51

It leads to global warming due to too much greenhouse effect