TOPIC 8 Earth And Atmospheric Science

Question 1

Number of carbons in a carbon chain and their names

Answer 1

1 meth-
2 Ethel-
3 prop-
4 But-
5 pent-
6 hex-

Question 2

Homologous series

Answer 2

Group of compounds with the same functional group and so react in similar ways

Question 3

Functional group

Answer 3

Group of atoms that determine how a compound generally reacts.

Question 4

What do you do if there’s more than one identical functional group?

Answer 4

Use di- for two
Tri- for 3
Tetra for 4

Question 5

Crude oil

Answer 5

A mixture of substances (mostly hydrocarbons of different lengths) which are separated through fractional distillation.

Question 6

Where does fractional distillation take place?

Answer 6

In a fractionating column with a temperature gradient (coolest at top, hottest at bottom).

Question 7

Where do larger hydrocarbons end up?

Answer 7

At the bottom of the fractionating column due to having higher bp’s.

Question 8

Where do shorter hydrocarbons end up?

Answer 8

At the top of the fractionating column due to having lower bps.

Question 9

What stops the liquid from remixing in the fractionating column?

Answer 9

Bubble caps make sure each fraction is separated into a mixture of hydrocarbons containing similar bps.

Question 10

Saturated hydrocarbon

Answer 10

Hydrocarbons containing only single bonds.

Question 11

Unsaturated hydrocarbons

Answer 11

Hydrocarbons containing double/triple bonds between carbon atoms.

Question 12

Number of carbons in carbon chain in gas and its use

Answer 12

1-3

Used for heating and cooking

Question 13

Number of carbon chains in petrol and its use

Answer 13

8

Used for fuel in cars

Question 14

Number of carbons in chain for kerosene and its use.

Answer 14

15

It’s used for aircraft fuel.

Question 15

Number of carbons in diesel and its use

Answer 15

20

Used for fuel in large vehicles

Question 16

Number of carbons in chain in fuel oil and its use

Answer 16

40

It’s used as fuel in large ships and in power stations.

Question 17

Number of carbons in chain for bitumen and its use

Answer 17

70+

Used in tarmac

Question 18

Viscosity

Answer 18

Resistance of tendency to flow

Question 19

Characteristics of longchain hydrocarbons

Answer 19

Viscous
Low ease of ignition and volatility
High bp

Question 20

Volatility

Answer 20

Tendency of a substance to vaporise

Question 21

Characteristics of short chain hydrocarbons

Answer 21

Low viscosity
V flammable and volatile
Low bp

Question 22

Cracking

Answer 22

Splitting up of low in demand longchain hydrocarbons to create shorter chain hydrocarbons that are high in demand. It’s a form of thermal decomposition.

Question 23

Give an example of cracking

Answer 23

Decane&raquo_space; octane + ethene

Question 24

How do you crack hydrocarbons in a lab

Answer 24

Vaporised hydrocarbons are passed over a powdered catalyst. Much energy is needed to break the bonds so cracking is carried out at 400—700 degrees Celsius .

Question 25

What’s the catalyst used in cracking?

Answer 25

Aluminium oxide

Question 26

What pressure is cracking carried out at?

Answer 26

70atm

Question 27

Word equation/ balanced equation for complete combustion of hydrocarbons

Answer 27

Hydrocarbon + oxygen&raquo_space; carbon dioxide + water
C3H8 +5O2&raquo_space; 3CO2 +4H2O

(Much energy is also released)

Question 28

Word equation for incomplete combustion of hydrocarbons

Answer 28

Hydrocarbon + limited oxygen&raquo_space; carbon dioxide + carbon monoxide + water + carbon composites

Question 29

Why’s carbon monoxide dangerous?

Answer 29

Because its colourless, odourless and sinks.
It binds to the haemoglobin in your red blood cells, replacing oxygen. This results in fainting, comas or even death. Some appliances like boilers produce this when faulty.

Question 30

Why are carbon composites (soot) bad?

Answer 30

They cause respiratory issues and make buildings/environment dirty. Can result in industrial melanism

Question 31

Acid rain

Answer 31

Burning of fossil fuels with sulfur impurities mean sulfur and oxygen react to form sulfur dioxide, this rises and dissolves into water in the clouds (forming sulfuric acid at a pH of roughly 4) which then falls as acid rain. This acidified lakes and soil, killing plants and animals. Erodes metals and statues/buildings. It’s even linked to some respiratory diseases.

Question 32

How are nitrogen oxides formed? What are their effects?

Answer 32

Car engines react nitrogen and oxygen together with heat to form nitrous oxides. These cause acid rain, photochemical smog and health issues.

Question 33

Reaction within hydrogen fuel cells

Answer 33

Hydrogen + oxygen&raquo_space; water (+energy!!)

Question 34

Advantages of hydrogen fuel cells

Answer 34

Is a clean fuel
Has no harmful pollutants
Obtained from water which is renewable via electrolysis of water.
Can be obtained from product.

Question 35

Disadvantages of hydrogen fuel cells

Answer 35

Require a special and expensive engine
Needs top be manufactured via electrolysis which is expensive and uses energy from fossil fuels which produces pollutants.
Highly flammable so requires a reinforced container
Expensive to buy

Question 36

What was the original atmosphere like?

Answer 36

We had a molten crust that was so hot that our atmosphere dispersed into space. After millions of years however, the crust cooled down and formed volcanoes. Intense volcanic for the first billion years went on to form the early atmosphere and oceans. MOSTLY CO2 AND LITTLE/NO OXYGEN.

Question 37

Which planets was the early atmosphere originally like?

Answer 37

Venus and mars today

Question 38

How did the oceans form?

Answer 38

Volcanic activity released nitrogen, water vapour and small parts of methane/ ammonia. The earth then cooled and condensed the water vapour to form the oceans.

Question 39

Why did the CO2 decrease?

Answer 39

Sea absorption: sea dissolved CO2 to form carbon precipitates (sediments on seabed) and marine shells. The bodies of the marine life going to form sedimentary rock.
Also algae (evolved 2.7billion years ago) and plants (1.7) photosynthesised to produce oxygen.

Question 40

Why did the oxygen increase in the early atmosphere?

Answer 40

Photosynthesis from algae/plants
As oxygen increased, simple organisms couldn’t cope with the environmental change and so they were killed which added more oxygen to the atmosphere for more complex life to form.
This created the OZONE LAYER.

Question 41

Photo synthesis word equation

Answer 41

Carbon dioxide + water >(light> glucose + oxygen

The glucose is stored as starch in a plant

Question 42

Why is the ozone layer good?

Answer 42

Because it blocks out harmful UV rays from the sun, enabling evolution of more complex life.

Question 43

Our atmosphere today

Answer 43

21% oxygen
0.03% CO2
78% nitrogen
0.9% argon

Question 44

Oxygen test

Answer 44

If it delights a glowing splint, oxygen is present.

Question 45

Greenhouse effect

Answer 45

The sun emits short wavelength UV radiation which reaches the earth’s surface and is absorbed and then re-emitted as long wave IR radiation. This IR is absorbed by greenhouse gases in the atmosphere (CO2, methane, water vapour).
These gases then re-radiate it in all directions, including back to earth which warms the earth’s surface. We enhance this effect by producing more greenhouse gases.

Question 46

How do you investigate the proportion of oxygen in the atmosphere?

Answer 46

Soak iron wool in acetic acid (catalyses reaction) and put into measuring cylinder that’s inverted into a container of water. Iron reacts w oxygen so water will rise to form the oxygen’s space. Leave until the difference in water volumen in the cylinder stops changing .
100*change in volume / start volume = % of oxygen in air.