Can be separated because
the hydrocarbons in different
fractions have different sized
molecules.
Intermolecular forces- forces between
molecules and are broken during boiling
Petrol- weak attractive forces
and are easily separated.
Less energy is needed and
has a low boiling point
because of this
Problems in extracting crude oil
Can damage birds feathers and cause deaths.
Oil producing nations can set high
prices and cause problems for future
supply
Naphtha- high demand for use
in medicines, plastics and
dyes
Using carbon fuels
Choosing fuels
Fossil fuels burning is
increasing because populations
are too
Government is concerned because of
the increasing carbon dioxide emissions
that result from fossil fuels
Countries with huge
populations (China, India) are
now using more fuel which
means more gas emissions
Can't be solved by one
country alone, trying to cut
carbon dioxide emissions in
the next 15-20 years.
Combustion
Burning hydrocarbons
in air produces carbon
dioxide and water.
methane + oxygen = carbon dioxide + water
Complete combustion- when a
fuel burns in plenty of oxygen
More energy is
released during
complete
combustion than
during incomplete
combustion
CH4 + 2CO2 = CO2 + 2H2O
Incomplete combustion
Carbon monoxide and soot is made
fuel + oxygen = carbon monoxide + water
or fuel + oxygen = carbon + water
2CH4+3O2 = 2CO + 4H2O
CH4 + O2 = C + 2H2O
Making Polymers
Hydrocarbons
(Alkanes and Alkenes)
Alkanes- 'Family' of hydrocarbons with
single convalent bonds only. They are saturated
Methane- CH4
Ethane-C2H6
Propane-C3H8
Butane-C4H10
Cn H2n+2
Alkenes- 'Family' of hydrocarbons with
double convalent bond between carbon
atoms(two shared pair of electrons) Unsaturated
Ethene- C2H4
Propene- C3H6
Butene- C4H8
Bromine test-when added, turns
colourless due to the new
compound formed by an addition
reaction - di-bromo compound
Polymerisation
Addition Polymerisation- process in which
many alkene monomers react to give a
polymer. Needs high pressure and a catalyst
Recognise by displayed formula by
looking for; long chain, pattern repeating
every two carbon atoms, two brackets
at the end and an n after the brackets
Involves the
reaction of many
unsaturated
monomer molecules
(alkenes) to form a
saturated polymer.
Displayed formula of an
addition polymer can be
constructed when the
displayed formula of its
monomer is given, and
vise-versa
Clean Air
Clean Air
Made up of 78%
nitrogen, 21%
oxygen and of
the remaining 1%
only 0.035% is
carbon dioxide
Carbon Dioxide has
increased due to
deforestation (less
photosynthesis takes
place) and increased
population, as the
energy requirements
increase
The atmosphere
Gases escaping the interior of the Earth
formed the original atmosphere. Plats
could photosynthesise which removed
carbon dioxide and added oxygen, so it
could reach its current level
Gases come
from the
centre of the
Earth through
volcanoes in a
process called
degassing.
One theory by scientists
said that the atmosphere
was originally in water
vapour and carbon
dioxide. This then
condensed to form
oceans and carbon
dioxide dissolved in it.
Nitrogen increased and
slowly overtime some
was removed.
Another is that over time, organisms that could
photosynthesise evolved and converted carbon
dioxide and water into oxygen. As the
percentage increased, the carbon dioxide
decreased and todays levels were reached.
Pollution control
Sulfur Dioxide is pollutant that
can cause difficulities for
people with asthma. Also
dissolve in water to form acid
rain.
Catalytic converter
in car- changes
carbon monoxide to
dioxide
In a catalytic converter- a reaction between nitric oxide and carbon monoxide
takes place on the surface. Two gases are formed and are natural components
of air- nitrogen and carbon dioxide
2CO + 2NO = N2 + 2CO2
Designer Polymers
Breathable polymers
Nylon- tough, lightweight, keeps water out, keeps uv light out but doesn't let water vapour
through. Means that sweat condesnses and makes the wearer wet and cold inside the jacket
GORE-TEX is waterproof and breathable. It's made of
PTFE- the holes are too small for water to pass through but
not big enough to pass through. Too fragile on it's own so it
is laminated onto nylon to produce a strong fabric.
Disposing of Polymers
Disposal of non-biodegradable
polymers means landfill sites get
filled quickly.
Disposal by burning waste plastics makes toxic gases.
Disposal by burning or using landfill sites
wastes the crude oil used to make the
polymers.
Stretchy polymers and rigid polymers
Held together by strong covalent bonds
Properties of plastics can be related to simple models of structure.
Plastics that have weak intermolecular
forces between polymers have low melting
points and can be stretched easily as the
polymer molecules can slide over each other.
Plastics that
have strong
forces
between the
polymers have
high melting
points, they
can't be
stretched and
are rigid
Cooking and food additives
Proteins and Carbohydrates
Protein molecules in eggs and
meat permanently change
shape when they're cooked
This is called Denaturing
Potatoes (Carbohydrates) are easier to
digest if it's cooked because; - the starch
grains swell up and spread out/the cell walls
rupture resulting in the loss of their rigid
structure and a softer texture is produced.
Baking Powder
Sodium Hydrogencarbonate
When it's heated it decomposes to
give carbon dioxide
Sodium Hydrogencarbonate = sodium carbonate + carbon dioxide + water
2NaHCO3 = Na2CO3 + CO2 + H2O
Emulsifiers
Molecules that have a
water loving part and
an oil or fat loving part
Oil/fat loving part goes into the fat
droplet
Help to keep oil and water from separating
Water loving part end bonds to the water molecules
The fat loving part end bonds to the oil or fat molecules
Water loving part end is attracted to the
water molecules which surround the oil,
keeping them together
Smells
Esters
Alcohol + acid = ester + water
Experiment; Acid is added to the alcohol and
heated. The condenser stops the gas from
escaping and helps it cool down so it can
react more. The condenser allows the
reaction to go on for longer..
Perfume properties
Evaporate easily, so that the particles can
be smelt
Be non-toxic so it doesn't posion you
Not react with water so it doesn't react
with sweat
Non-irritant so doesn't harm the skin
Be insoluble in water so it can't be
washed off easily
Solutions
A solution is a mixture of solvent
and solute that doesn't spread out
Esters can be used as solvents
Particles
Evaporation of perfume can be
explained by the kinetic theory.
In order to evaporate, particles of a liquid need
sufficient kinetic energy to overcome the forces of
attraction to other molecules in the liquid
Only weak attractions exist between particles of the
liquid perfume so it's easy to overcome these attractions
as they have sufficient kinetic energy
Water will
not dissolve
nail varnish
colours
because the
attraction
between the
water and
water
molecules is
stronger
than the
attraction
between the
water and
nail varnish
molecules.
Paints and Pigments
Colloids
Paint is a colloid where the particles are mixed
and dispersed with particles of a liquid but are
not dissolved
The
components of a
colloid won't
separate
because the
particles are
scattered
throughout the
mixture
Paint drying
Emulsion paints are water based paints that dry when the solvent evaporates
Oil paints dry because the solvent
evaporates or the oil is oxidised by
atmospheric oxygen
Thermochromic pigments
Change colour at different temperatures. Used
as thermometers/cups/electric kettles/baby
spoons or bath toys.
Can be added to
acrylics to make
even more colour
changes.
Phosphorescent pigments glow in
the dark because they store and
absorb energy and they release
energy as light over a period of time.
They are much more safer than the
older alternative radioactive paints