alkanes and haloalkanes Flashcards
what are alkanes
They are saturated hydrocarbons
they are molecules made of only hydrogen and carbon atoms
each of their carbon atoms forms four single bonds
outline the process of fractional distillation
crude oil vaporised at around 350 degrees celcius
vaporised crude oil goes into borrom of fractioning column rises up through the trays
largest hydrocarbons don’t vaporise at all they just run to the bottom and form a residue
as crude oil vapour goes up fractioning column it gets cooler
the fractions condense at their boiling points and are collected
alkanes with lowest boiling points don’t condense and are collected as gases at the top
what do longer chain hydrocarbons undergo to form shorter chain hydrocarbons and alkenes that are more useful
longer chain hydrocarbons undergo cracking to form shorter chain hydrocarbons and alkenes
what does cracking involve
the breaking of C-C bonds in the alkanes
what are the two types of cracking
thermal cracking
catalytic cracking
what are the conditions of thermal cracking
high temperature- 1000 degrees celcius
high pressure around 70atm
what are the products of thermal cracking
lots of alkenes
useful for production of polymers
what are the conditions of catalytic cracking
zeolite catalyst
slight pressure
high temperature of around 500 degrees celcius
what are the products of catalytic cracking
aromatic hydrocarbons
alkanes needed to produce motor fuels
what are the benifits of using a catalyst in catalytic cracking
cuts costs
reactions can be done at a low pressure and lower temperature
when is nitrogen monoxide produced
when the high pressure and temperature in a car engine causes the nitrogen and oxygen atoms in the air to react together
what are the two reactions of nitrogen and oxygen in the engine of a car
N2 + O2—— 2NO
2NO + 02—— 2NO2
what are the two reactions that occur in a catalytic converter of a car
2NO —– N2 + O2
2NO + 2CO—– N2 + 2CO2
how is sulfur dioxide formed
when a fossil fuel containing sulfur impurities is burnt
what is a photochemical reaction
a reaction started by UV light
