chemistry topic 5 fuels Flashcards
elements combined together in propane
hydrogen and carbon
word equation for complete combustion
hydrocarbon + oxygen -> carbon dioxide + water
why are fuels burned?
they release energy
what product is formed when there is incomplete combustion?
carbon monoxide
what’s cracking?
when larger less useful hydrocarbons are broken down into smaller more useful ones
two substances that cause acid rain
sulphur dioxide and nitrogen oxide
two environmental problems caused by acid rain
acid rain removed waxy layer in leaves (causes water loss and death)
sulphuric and nitric acids are strong. they donate protons which attack gills of fish and other aquatic life
acid rain can cause weathering in two materials most at risk
limestone and marble
order of fractional distillation
- gases (heating and cooking)
- petrol (fuel for cars)
- kerosene (fuel for aircraft engines)
- diesel (fuel for diesel engines - cars, lorries, trains)
- fuel oil (ships and power stations)
- bitumen (surface roads and roofs)
what is the acrostic u made for the order of fractional distillation
girls put keys down for boys
(don’t ask)
what do fractional distillation fractions consist of
hydrocarbons of similar chain lengths
hydrocarbons of similar properties and boiling points
how does the temperature change in the fractional distillation column
cool at the top
hot at the bottom
process of fractional distillation to separate crude oil
crude oil enters fractionating column and is heated so vapours rise
vapours of hydrocarbons with very high boiling points condense into liquid immediately and are tapped off at the bottom of the column
low boiling points rise up and condense at the top to be tapped off
they condense at different heights according to boiling points and are tapped off as liquids
which hydrocarbons are collected at the top of the fractionating column
smaller hydrocarbons
which hydrocarbons are collected at the lower sections of the fractionating column
bigger hydrocarbons
what bonds do alkanes have
single
chemical properties
boiling point - intermolecular forces of attraction are greater
need more energy to break
increase boiling point
viscosity - ease of flow of liquid
high viscosity - thick and flow less easily
viscosity also increases with increasing chain length
ease of ignition - smaller hydrocarbons are more flammable
good for fuels (more energy when they burn)
examples of fossil fuels
coal, oil, natural gas, oil shales
what does burning of fossil fuels release
carbon dioxide, carbon monoxide, oxide of nitrogen and oxides of sulphur
complete combustion occurs when there is what
excess oxygen
why is carbon monoxide toxic
it binds with haemoglobin in red blood cells so it moves carbon monoxide around ur body instead of oxygen
u go unconscious and die
simple molecules
covalent bonds
weak intermolecular forces
low boiling and melting point
poor conductor of electricity
often a gas or liquid at room temp
polymer chains
covalent bonds
many weak intermolecular forces over long molecules
solid at room temp
poor conductor of electricity
alkenes have what
double bonds
saturated hydrocarbons contain what
single bonds
unsaturated hydrocarbons contain what
double bonds
methanoic acid formula
HCOOH
ethan ooc acid formula
CH3COOH
propanoic acod formula
C2H5COOH
butanoic acid formula
C3H7COOH
carboxylic acid reaction
metal + carboxylic acid -> salt + hydrogen (MASH)
catalytic converters are designed to what
reduce polluting gases produced in car exhausts
they contain transition metal catalysts
a series of redox reactions occur which neutralise the pollutant gases
carbon monoxide is oxidised to carbon dioxide
unburned hydrocarbons are oxidised to CO2 and water
why is cracking necessary
to convert fractions with less demands into more useful ones
what is bromine test
if it is an alkane then bromine stays orange
if it is alkene, bromine goes colourless
what is a polymer
a substance of high relative molecular mass made up of small repeating units
what’s a natural polymer
DNA
what are proteins
polymers based on amino acids
