Fuels and Earth Science T8

Question 1

What is crude oil?

Answer 1

Our main source of hydrocarbons and is used as a raw material to create lots of useful substances used in the petrochemical industry

Question 2

How is crude oil formed?

Answer 2

It’s formed underground, over millions of years ( at high temperatures and pressures) from the buried remains of plants and animals. It’s a non renewable resource, so 1 day it will run out

Question 3

What are hydrocarbons?

Answer 3

Compounds that only contain carbon and hydrogen. The hydrocarbons found in crude oil are mostly alkanes (hydrocarbons with the general formula of CnH2n+2)

Question 4

What are fractions?

Answer 4

Simpler, more useful mixtures containing groups of hydrocarbons of similar lengths. The fractions (eg petrol, kerosene and diesel) are non renewable fossil fuels

Question 5

What do longer hydrocarbons have in terms of temperature?

Answer 5

A higher boiling point, they turn back into liquids and drain out of the column early on

Question 6

What is petrol used as?

Answer 6

Petrol is used as fuel in cars

Question 7

What is kerosene used for?

Answer 7

Kerosene is used as a fuel in aircraft

Question 8

What is diesel used for?

Answer 8

Diesel is used as a fuel in some cars and larger vehicles e.g trains

Question 9

What is fuel oil used for?

Answer 9

Fuel oil is used as a fuel for large ships and also in some power stations

Question 10

What is bitumen used for?

Answer 10

Bitumen is used to surface roads and roofs

Question 11

What are refinery gases used for?

Answer 11

The gases in this fraction are used in domestic heating and cooking

Question 12

What is a homologous series?

Answer 12

The homologous series is a family of molecules which have the same general formula and share similar chemical properties

Question 13

How much does each molecular formula differ from a neighbouring compound?

Answer 13

By CH2

Question 14

What are 2 different homologous series of hydrocarbons?

Answer 14

Alkanes and alkenes

Question 15

What does viscosity mean?

Answer 15

Measures how easily a substance flows

Question 16

Which hydrocarbons are easier to ignite?

Answer 16

Shorter hydrocarbons as they have lower boiling points

Question 17

Why do the intermolecular forces break easier between smaller molecules than larger molecules?

Answer 17

The forces are much stronger between big molecules than smaller molecules. Thats why big molecules have higher boiling points

Question 18

What state are longer hydrocarbons at room temperature?

Answer 18

Liquids. They have much higher boiling points and are harder to ignite

Question 19

Why do hydrocarbons make good fuels?

Answer 19

Because the combustion reactions that happen when you burn them in oxygen give out lots of energy

Question 20

What is complete combustion?

Answer 20

When you burn hydrocarbons in plenty of oxygen, the only products are carbon dioxide and water

Question 21

How does incomplete combustion happen?

Answer 21

Incomplete combustion occurs when a hydrocarbon burns in a limited supply of oxygen. It produces carbon monoxide and carbon in the form of soot

Question 22

How can carbon dioxide be dangerous?

Answer 22

Carbon dioxide can combine with red blood cells and stop your blood from doing its proper job of carrying oxygen around you body, a lack of oxygen can lead to fainting, a coma or even death

Question 23

How are sulphur dioxide and nitrogen oxide produced?

Answer 23

From burning fossil fuels. The sulfur comes from the impurities in the fossil fuel

Question 24

How is acid rain formed?

Answer 24

When sulfur dioxide mixes with clouds, it forms dilute sulfuric acid. This falls as acid rain. Acid rain cause lakes to turn acidic and thus killing many animals and plants

Question 25

What is photochemical smog?

Answer 25

Photochemical smog is a type of air pollution that can cause breathing difficulties, headaches and tiredness

Question 26

What are the pros of used hydrogen as a fuel?

Answer 26

Hydrogen is very clean, in a hydrogen fuel cell, hydrogen combines with oxygen to produce energy, and the only waste product is water, no nasty pollutants like carbon dioxide

Question 27

What are the cons of used hydrogen for fuel?

Answer 27

You need a special, expensive engine. Hydrogen gas also needs to be manufactured which is expensive and often uses energy from another source, this energy often comes from burning fossil fuels which produce pollutants

Question 28

What is cracking?

Answer 28

Cracking turns long saturated (alkane) molecules into smaller unsaturated (alkene) and alkane molecules (which are much more useful)

Question 29

Why would you crack molecules?

Answer 29

To get more resources which are in higher demand such as diesel and petrol

Question 30

What can alkene molecules be used for?

Answer 30

Making polymers

Question 31

In what order does a fractional distillation machine distill substances?

Answer 31

``` Refinery gases Petrol Kerosene Diesel oil Fuel oil Bitumen ```

Question 32

What was the atmosphere of the earth like millions of years ago?

Answer 32

There was no atmosphere

Question 33

What happened when the earths surface cooled and a thin crust formed?

Answer 33

Volcanos erupted, releasing gases from inside the earth, this degassing released mainly carbon dioxide, but also steam, methane and ammonia.

Question 34

What happened when the volcanos stopped erupting?

Answer 34

The early atmosphere now only contained mostly CO2 and water vapour

Question 35

How was nitrogen gas formed in the early atmosphere?

Answer 35

Nitrogen gas was formed by ammonia reacting with oxygen and it was also released by denitrifying bacteria.

Question 36

Why did the level of nitrogen increase instead of go decrease?

Answer 36

Nitrogen isn’t very reactive so it increased because it was being made and not breaking down

Question 37

How did the early atmosphere get rid of its carbon dioxide?

Answer 37

Many green plants evolved over most of the earth and removed carbon dioxide and created oxygen

Question 38

Why is the ozone level (O3) help?

Answer 38

It blocked the harmful rays from the sun

Question 39

What is the test for oxygen?

Answer 39

You can test for oxygen by checking if the gas will relight a glowj g splint

Question 40

How do more people mean for the atmosphere?

Answer 40

More people mean more fossil fuels need to be burned for their lighting and heating. More land also needs to be created which leads to deforestation. Deforestation means that the 1 main source for removing oxygen from our atmosphere is slowly being reduced

Question 41

What does the sun give out?

Answer 41

Electromagnetic radiation

Question 42

What happens to the electromagnetic radiation as it reaches our atmosphere?

Answer 42

Some electromagnetic radiation passes through our atmosphere. The electromagnetic radiation with short wavelengths are absorbed by the earth, warming the planet

Question 43

What are greenhouse gases?

Answer 43

Greenhouse gases are the gases in the atmosphere that can absorb and reflect heat radiation. They’re only present in small amounts. Carbon dioxide ,water vapour and methane are 3 green house gases

Question 44

What happens when there are more green house gases?

Answer 44

More radiation is absorbed by the earth from the sun, warming our planet

Question 45

Why is methane a problem in recent years?

Answer 45

Because methane is a super effective green house gas and it is produced by farming livestock such as cattle and sheep

Question 46

What does anthropogenic mean?

Answer 46

It means ‘caused by humans’. Most scientists believe that global warming is anthropogenic

Question 47

What ways can we see the global levels of carbon dioxide in the past?

Answer 47

Tree rings, fossil and gas bubbles trapped in ice sheets however these method are not very accurate and are less representative of global levels

Question 48

How could we reduce carbon dioxide emissions?

Answer 48

Instead of driving, we could cycle or turning your central heating down when you leave the house