topic 8

Question 1

What is crude oil?

Answer 1

A finite, non renewable resource made from dead plants and animals.

Question 2

Explain the method of separation of crude oil.

Answer 2

• Crude oil is heated strongly to evaporate it
  -The column is hottest at the bottom and coldest at the top
  -Vapours rise up the column and cool down
• The vapours condense and become liquids when they reach the part of the column just below their boiling point
• The liquid condenses into a tray and is piped away
• The vapours with the lowest boiling points never condense and leave the top of the column as a mixture of gases
• Bitumen has the highest boiling point and leaves the bottom of the column as a hot liquid

Question 3

Are fractions obtained by the separation of crude oil pure?

Answer 3

No

Question 4

What are examples of small chain substances in crude oil?

Answer 4

gasoline, methane

Question 5

What are examples of larger chain substances in crude oil

Answer 5

(In order from smallest chain:) Kerosene, Diesel, Fuel oil, Bitumen

Question 6

Give a use for kerosene

Answer 6

Aircraft fuel

Question 7

Give a use for fuel oil

Answer 7

power stations and ship fuel

Question 8

Give a use for bitumen

Answer 8

roofing or roads

Question 9

Why is Carbon Monoxide toxic to humans?

Answer 9

It displaces oxygen in the blood stream, depriving vital organs of oxygen

Question 10

What problems does soot cause for humans?

Answer 10

asthma, heart diseases and cancer

Question 11

What problems does sulphur dioxide cause?

Answer 11

Irritates eyes and restricts breathing. Acid rain

Question 12

How are nitrogen oxides formed?

Answer 12

high temperatures cause nitrogen to react. (For example, a lightning bolt can split a triple bonded N2 molecule in the air. These quickly bond to surrounding oxygen molecules, forming nitrogen oxide)

Question 13

Why are nitrogen oxides bad?

Answer 13

They can damage lungs and cause acid rain

Question 14

What is cracking?

Answer 14

Breaking covalent bonds in larger chain hydrocarbon molecules to form smaller hydrocarbons

Question 15

What does cracking always form?

Answer 15

An alkene and an alkane

Question 16

How do hydrogen fuel cells work?

Answer 16

Hydrogen reacts with oxygen without burning. The energy released is used to generate electricity

Question 17

What are the advantages of using hydrogen as fuel?

Answer 17

• Renewable
• Zero emission
• More effective
• More efficient

Question 18

What are the disadvantages of using hydrogen as a fuel?

Answer 18

• Pure hydrogen is difficult and expensive to obtain
• Flammable
• Creation of pure hydrogen is usually powered by fossil fuels

Question 19

Explain the development of Earth’s current atmosphere.

Answer 19

• The Earth’s early atmosphere was similar to Mars or Venus due to intense volcanic activity
• The atmosphere was mainly carbon dioxide
• The Earth cooled, causing water vapour to condense, forming the oceans. CO2 dissolved into the oceans, reducing it’s atmospheric levels
• Cyanobacteria in the ocean photosynthesise, decreasing CO2 further
• The atmosphere is now around 80% nitrogen, 20% oxygen, with trace amount of carbon dioxide