Topic 6B Flashcards
difference between thermal and catalytic cracking
Thermal Catalytic
-1200k + 700kPa -700k and slight
-produces lots of alkenes pressure
and some alkanes -produces branched
-can be used on bitumen alkanes
-produces arenes
how are alkanes rules obtained
cracking, fractional distillation and reforming of crude oil
what is reforming of crude oil
done to straight chain alkanes to produce branched and cyclic alkanes because they have higher octane numbers so they burn smoother and more efficiently
pentane—> cyclopentane + H2
Pollution of combustion of alkane fuels
CO
Oxides of nitrogen
-nitrogen in air reacts with Oxygen in combustion and this reacts with water to form acid rain
Sulphur dioxide
-sulphur impurities in hydrocarbons causes acid rain
Carbon particulates (soot)
-contributes to global dimming and blocks pipes and chimneys
Unburned hydrocarbons
-disrupts Healthy cell growth
-causes smog and air pollution
-causes acid rain
How does a catalytic converter solve problems
fitted to exhaust of cars to stop harmful gases being emitted
it uses a platinum catalyst to convert harmful gases
has a honeycomb structure
Carbon monoxide and nitrogen oxides react to form carbon dioxide, nitrogen and oxygen
fossil fuels as a fuel advantages and disadvantages
Easy
Limited resource
locked up Co2 in aquatic mammals released
What is a radical and how is it formed
A species with an unpaired electron which it represented in mechanisms by a single dot
It is formed by homolytic fission of a covalent bond
What is heterolytic fission
when a covalent bond breaks and one atom takes both the electrons
Cl-H —> Cl- + H+
Chlorine takes both
What is homolytic fission
when a covalent bond breaks and each atom takes an electron
Cl-Cl —> *Cl + *Cl
Two chlorine radicals
