3.2 Alkanes And Haloalakanes

Question 1

What is the first fraction to condense and at what temp.?

Answer 1

Mineral oil at 340°C

Question 2

What is the second fraction to condense and at what temp.?

Answer 2

Gas oil (diesel) at 250°C

Question 3

What is the third fraction to condense and at what temp.?

Answer 3

Kerosene at 180°C

Question 4

What is the fourth fraction to condense and at what temp.?

Answer 4

Naphtha at 110°C

Question 5

What is the fifth fraction to condense and at what temp.?

Answer 5

Petrol at 40°C

Question 6

What comes out the top of the distillery?

Answer 6

Gases such as LPG which don’t condense even at lower temperatures

Question 7

What comes out the bottom of the distillery?

Answer 7

Residue such as bitumin and fuel oil which are extremely long hydrocarbons that have a boiling point over 350°C

Question 8

What are the conditions for thermal cracking?

Answer 8

1000°C and a pressure of 70atm

Question 9

What are the products of thermal cracking?

Answer 9

A large proportion of alkenes such as ethene and straight chain alkanes and alkenes

Question 10

What are the conditions for catalytic cracking?

Answer 10

450°C, slightly over 1atm and a zeolite (aluminium and silicon oxides) catalyst

Question 11

What are the products of catalytic cracking?

Answer 11

A high proportion of branched alkenes and alkanes, aromatic alkanes (such as benzene) and cyclic alkanes

Question 12

At what temp. is the crude oil heated before it enters the fractional distillation column?

Answer 12

Vaporised at 350°C

Question 13

Why is carbon monoxide poisonous?

Answer 13

Because it binds to the same sites on haemoglobin molecules as oxygen molecules so oxygen supplies around the bodies are limited

Question 14

Why is soot bad if it is realeased?

Answer 14

It can cause breathing problems, especially for asthmatics

Question 15

How is sulfuric acid formed?

Answer 15

Sulphur impurities in hydrocarbons are released as sulphur dioxide. When the sulphur dioxide reacts with water vapour in the atmosphere it forms sulfurous acid (H₂SO₃) which is oxidised to form sulfuric acid (H₂SO₄).

Question 16

What are NO_x’s, how are they formed and why are they bad for the environment?

Answer 16

In the high temperatures of combustion engines (>1000°C) the nitrogen in the air reacts with oxygen forming nitrogen oxides known as NO_x’s. They can also cause acid rain by reacting with water vapour to form HNO₃ and form ground level ozone (O₃) which is a major componant of smog which irritates the eyes.

Question 17

What does FGD stand for and how does it work?

Answer 17

Flue gas desulfurization is where sulfur dioxide is removed from power plant gas exausts by using a base such as calcium oxide.

Question 18

What is the reduction reaction of nitrogen oxide?

Answer 18

2NO→N₂+O₂

Question 19

What metals are used in catalytic converters and how are they made more effective?

Answer 19

Polonium and platinum are both used. The metals are on a honeycomb structure to increase the surface area there to to react on.