Alkanes Flashcards
What are alkanes
Saturated hydrocarbons
Are alkanes soluble in water
Nope
Describe the steps for fractional distillation
Heated till most is vaporised, tower which is cooler on top, vapours rise until it condenses into trays, shorter chained hydrocarbons higher up
Why is fractional distillation required
Petroleum is a mixture containing alkane hydrocarbons of different lengths
What is cracking used for
Shorter, more useful alkanes are produced.
Alkenes can also be produced
Describe thermal cracking
High pressure, high temperature, produces a lot of alkenes
Describe catalytic cracking
Slight pressure, high temperature, zeolite catalyst, produces motor fuels and aromatic hydrocarbons
When does incomplete combustion occur
Not enough oxygen
What is produced with incomplete combustion
CO or C
How are nitrogen oxides formed in cars
This happens in petrol engines due to high temperatures, causing oxygen to react with nitrogen in the air
How is sulphuric acid produced
Sulfur impurities in crude oil, which is then burnt
Problem with water vapour
It’s a greenhouse gas
How are catalytic convertors used
Contains a honeycomb shape with platinum around as catalyst. Reacts CO with NO to produce N2 and CO2
How can sulfur be removed from flue gases
Calcium oxide, water and oxygen is reacted with SO2 to make calcium sulphate
Catalyst for catalytic convertors
Platinum or rhodium
