alkanes

what is crude oil made from?

dif length alkanes with dif properties + uses

from plankton

why are alkanes insoluble in water?

they are non-polar (uncharged)

form oily layer when mixed with water

why do alkanes have low MPs/BPs?

they contain weak vdw forces

why do longer chained alkanes have higher BPs?

more molecules, so more vdw forces

molecules closer together, so forces act over a larger area, making them stronger

so more energy required to overcome

what are fractions?

crude oil separated into groups of similar lengths + properties

process of fractional distillation?

crude oil heated to vaporise

vapour and remaining liquid passed through fractioning tower

temp gradient in tower; hotter at bottom, cooler at top

vapour cools + condenses as it rises

higher BP condense at the bottom, lower BP at the top

impurity of crude oil?

sulphur, which reacts to form sulphur dioxide (acid rain)

properties of larger fractions?

more viscous, less flammable, less volatile

uses of fractioned/shorter alkenes?

petrol, fuel, camping gases

what is cracking?

turning longer chained HCs into shorter ones by breaking covalent bonds

thermal cracking?

heated to break bonds

high temp + pressure

produces lots of alkenes

catalytic cracking?

uses zeolite catalyst

high temp, moderate pressures

produces cyclic + aromatic compounds

what type of reaction is combustion?

exothermic as it releases energy

incomplete combustion products?

C or CO + water

pollutant products of incomplete combustion?

CO2 greenhouse gas

carbon soot

CO binds to blood

sulphur dioxide acid rain\

nitrogen oxides

how are nitrogen oxides formed?

nitrogen reacts w/ oxygen in the air

can react with water to form acid rainw

what is flue gas desulphurisation?

removing sulphur dioxide from chimneys to form drywall

inside coated with CaO or CaCO3

which are basic so react w/ acidic SO2

neutralisation

how do catalytic converters work?

convert dangerous gases into safer ones (CO → CO2)

via a platinum catalyst

that the gases bind to

honeycomb structure = higher SA

equation for catalytic converter reaction?

2CO + 2NO → 2CO2 + N2

global warming process?

earth emits IR as it cools

greenhouse gases like CO2 absorb this radiation

as they leave the atmosphere, their bonds stretch/vibrate

re-emitting the radiation + warming the planet