Alkanes

Question 1

hey kid

Answer 1

whassup?

Question 2

What are the conditions for thermal cracking?

Answer 2

• High pressure (7000kPa)

- High temperature (400°C to 900°C)

Question 3

What are the conditions for catalytic cracking?

Answer 3

• Low pressure
• High temperature (450°C)
• Zeolite catalyst

Question 4

What are the products of thermal cracking?

Answer 4

• Mostly alkenes

- With some hydrogen

Question 5

What are the products of catalytic cracking?

Answer 5

• Branched alkanes
• Cycloalkanes
• Aromatic hydrocarbons

Question 6

Why are branched and cyclic hydrocarbons used in motor fuel?

Answer 6

They burn more cleanly

Question 7

Which method of cracking is cheaper?

Answer 7

Catalytic cracking because a lower pressure needs to be maintained.

Question 8

What is flue gas desulphurisation? Give an equation.

Answer 8

Flue gas desulphurisation is the removal of SO2 from the waste gases of furnaces (found in factories) by passing the waste gases through a scrubber containing calcium oxide in a neutralisation reaction.

SO2 + CaO -> CaSO3

Question 9

What is the environmental consequence of the release of NO?

Answer 9

The formation of NO2 which causes acid rain.

Question 10

What is the environmental consequences of unburnt hydrocarbons?

Answer 10

Smog forms.

Question 11

What is the environmental consequence of soot?

Answer 11

Soot can cause global dimming and respiratory problems.

Question 12

In terms of their physical structure what are catalytic converters?

Answer 12

Platinum/palladium/rhodium covering a ceramic honeycomb.

Question 13

What do catalytic converters do?

Answer 13

Remove nitrogen monoxides and carbon monoxides and unburnt hydrocarbons from the exhaust fumes of cars.

Question 14

What are two equations that show the reactions inside catalytic converters?

Answer 14

2CO + 2NO -> 2CO2 + N2

C8H18 + 25NO -> 8CO2 + 12.5N2 + 9H2O