Acid rain:
Rain that is more acidic than
normal, has a pH lower than
5.2.
Alkane:
A hydrocarbon in which all
the bonds between the
carbon atoms are single
bonds.
Alkene:
A hydrocarbon in which
there are one or more
double bonds between
carbon atoms.
Biodegradable:
A substance that can be
broken down by
microorganisms.
Biodiesel:
Diesel fuel made from plant
material.
Biofuel:
A fuel made from plants or
microorganisms.
Boiling point:
Temperature at which a
substance changes from a
liquid to a gas.
Bonds:
The way in which atoms in
molecules are joined.
Bromine test:
A test for unsaturation.
Bromine water turns
colourless when mixed with
an unsaturated molecule.
Bromine water:
A solution of bromine in
water that turns colourless
when mixed with an
unsaturated molecule.
Carbon monoxide:
A toxic gas (CO), it is made
during incomplete
combustion. It replaces
oxygen in the blood and so
reduces the amount of
oxygen carried around the
body.
Carbon neutral:
Whereby the carbon dioxide
added to the atmosphere
when the fuel is burnt is only
replacing that which was
removed from the
atmosphere, during
photosynthesis, when the
plant was growing.
Therefore overall no more
carbon dioxide is being
added to the atmosphere.
Climate change:
The idea that the Earth’s
climate is changing. Many
scientists believe this is
linked to increasing carbon
dioxide levels.
Combustion:
Chemical reaction when
substances burn, combining
with oxygen to produce heat
and waste products such as
carbon dioxide.
Complete combustion:
Combustion of
hydrocarbons with enough
oxygen present to convert
all the fuel into carbon
dioxide and water.
Cracking:
A type of chemical reaction
in which large alkane
molecules are decomposed
into two or more smaller
molecules to form smaller
alkanes and alkenes.
Crude oil:
A mixture of hydrocarbons
formed from dead
microscopic organisms by
heat and pressure over
millions of years.
Double bond:
When two bonds join a pair
of the same atoms (usually
two carbon atoms).
Ethanol:
A fuel made by processing
sugar beet or sugar cane.
Fossil fuel:
Non-renewable fuels such as
coal, oil and natural gas
that have formed over
millions of years from dead
plants and animals.
Fractional distillation:
A method of separating a
mixture of liquids with
different boiling points into
individual components
(fractions).
Fraction:
A component of a mixture
that has been separated by
fractional distillation.
Fuel cell:
A device which produces
electricity from hydrogen
and oxygen without
burning.
Hydrocarbon molecules:
A compound of hydrogen
and carbon only.
Ignite:
To start burning.
Incinerated:
Burnt, i.e. waste.
Incomplete combustion:
Combustion that occurs
without enough oxygen to
completely oxidise all the
fuel. Incomplete
combustion of hydrocarbons
produces carbon dioxide,
carbon monoxide and
carbon (soot).
Limewater:
A solution of calcium
hydroxide that turns milky
when carbon dioxide is
bubbled through it.
Polymer:
A long molecule made
byjoining many smaller
molecules (monomers)
together.
Mixture:
A substance containing two
or more different
substances that are not
joined together.
Polymerisation:
The process of making a
polymer.
Monomer:
Small molecule used to
make a polymer.
Non-renewable resource:
Resources that cannot be
replaced once they have
been used. These will
eventually run out.
Renewable:
Something that can be
made without diminishing
the resources used to make
it, such as biofuels made
from plants that can be
grown again.
Plastics:
The common name for
many polymers.
Saturated:
A molecule which contains
only single bonds between
the carbon atoms and has
the maximum possible
number of atoms attached
to the carbon chain.
Poly(chloroethene)
A polymer made from
chloroethene monomers.
Also known as PVC.
Soot:
Tiny particles of solid carbon
produced by incomplete
combustion.
Poly(ethene):
A polymer made from
ethane monomers.
Poly(propene):
A polymer made from
propene monomers.
Unsaturated:
A molecule which contains
one or more double bonds
between the carbon atoms,
allowing extra atoms to be
added on to the carbon
chain.
Poly(tetrafluoroethene)
The chemical name for
PTFE, which is also known as
Teflon.
Viscosity:
How thick or runny a liquid
is. Low viscosity is very
runny, high viscosity is thick.