O- Alkanes =)

Question 1

What are the conditions of catalytic cracking? (2)

Answer 1

1. zeolite catalyst
2. slight/ moderate pressure

Question 2

An excess of methane reacts with chlorine in the presence of ultraviolet radiation.
What are the main products of this reaction? (1)

Answer 2

CH3Cl + HCl

Question 3

What are the conditions & products of catalytic cracking of alkanes?

Answer 3

conditions:
1. slight pressure
2. high temp

products:
1. branched alkanes
2. aromatics

Question 4

What is the purpose of fractional distillation in forming naphtha from crude oil? (1)

Answer 4

• separate into mixtures of compounds w/ similar bp

Question 5

The combustion of petrol in car engines produces the pollutant nitrogen monoxide.
Give an equation for a reaction that removes nitrogen monoxide in a catalytic converter. (1)

Answer 5

2NO + 2CO –> N2 + 2CO2

Question 6

Why is UV light needed for the reaction between propane and chlorine? (1)

Answer 6

provides energy to break covalent bond in Cl2 to form Cl free radicals

Question 7

Explain how carbon dioxide causes global warming. (2)

Answer 7

• C=O bonds in CO2 absrob IR radiation
• IR radiation emitted by the earth x escape from atmosphere

Question 8

Carbon dioxide is formed when petrol is burned.
Carbon dioxide acta as a greenhouse gas when it absorbs infrared radiation.
Give a reason why carbon dioxide absorbs infrared radiation. (1)

Answer 8

C=O bonds vibrate at same freq. as IR

Question 9

Most scientists believe that the concentration of ozone in the upper atmosphere should not be allowed to decrease.
Which statement is a correct reason for this belief?
A. Ozone helps to prevent global warming
B. Ozone is an efficient disinfectant
C. Ozone helps to remove pollutants such as chloroalkanes
D. Ozone absorbs ultraviolet radiation

Answer 9

D!