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EARLSTON HIGH SCHOOL
HIGHER CHEMISTRY
GLOSSARY
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UNIT 1
Activation energy
ENERGY MATTERS
The minimum KE required by colliding molecules to form
an activated complex.
Activated complex
An unstable arrangement of atoms formed at the
maximum of the potential energy barrier during a
reaction.
Active site
The point on the surface of the catalyst where adsorption
occurs.
Adsorption
Bonding onto the surface of a substance (eg a catalyst).
Anomalous
Unusual – not following the expected trend.
Avogadro constant
The number of formula units in 1 mole (6.02 x 1023).
Catalyst
A substance which increases the rate of reaction and is
recovered unchanged at the end.
Catalyst poisoning
A substance is preferentially absorbed onto the surface of
the catalyst preventing adsorption by the substrate eg
lead poisons the catalyst in catalytic converters.
Catalytic converter
Fitted to cards to catalyse the conversion of poisonous
carbon monoxide and oxides of nitrogen to CO2 and N2.
Collision theory
A theory used to explain the effects of concentration and
surface area on reaction rates.
Contact process
Industrial process to manufacture sulphuric acid using
the catalyst vanadium (V) oxide.
Covalent bond
Atoms are held together by electrostatic forces of
attraction between positively charged nuclei and
negatively charged shared electrons.
Covalent network
A giant lattice of covalently bonded atoms.
Delocalised
Not attached to one particular atom.
Dipole
Results from charge separation within particles –
particles have oppositely charged ends.
Discrete
Separate.
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Electrolysis
Production of an element from a compound, either
molten or in a solution, by passing electricity through it.
Electronegativity
Attraction of atoms for bonding electrons. Values
increase across a period and decrease down a group.
Elementary entity
Could refer to atoms, molecules, ions, ion pairs, electrons
or other particles. Avogadro’s number of them in a mole.
Endothermic
Heat is taken in during the reaction. ∆H is positive.
Energy distribution
diagrams
Diagrams to show the kinetic energy distributed
throughout a number of particles.
Enthalpy change (∆H)
The heat of reaction or the difference in energy between
products and reactants in kilojoules per mole can be
calculated using cm ∆T.
Enthalpy of combustion
The enthalpy change when one mole of a substance
burns completely in oxygen.
Enthalpy of neutralisation
Energy change when one mole of water is produced in a
neutralisation reaction.
Enthalpy of solution
Energy change when one mole of a substance dissolves
completely in water.
Enzyme
A biological catalyst. Catalyse reactions taking place in
living cells and used in many industrial processes.
Excess
There is more than enough of one reactant so some of it
remains unchanged.
Exothermic
Heat is given out during the reaction. ∆H is negative.
First ionisation enthalpy
Energy required to remove one electron from each atom
in a mole of atoms in the gaseous state.
Fullerenes
Recently discovered forms of carbon in the form of
molecular balls (bucky balls) or tubes.
Group
A column of the periodic table.
Haber Process
Catalytic conversion of nitrogen and hydrogen to
ammonia using iron as catalyst.
Heterogeneous
In a different physical state.
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Homogeneous
In the same physical state.
Hydration of ions
Attractive forces between a charged ions and polar water
molecules.
Hydrogen bonding
Intermolecular electrostatic attractions found in
compounds containing hydrogen bonded to an atom with
a strong attraction for bonding electrons (N.F.O.Cl.).
Stronger than other intermolecular bonds but weaker
than covalent bonds.
Inhibitor
Substance used to slow down a reaction eg antioxidants
in rubber.
Intermolecular forces
Forces of attraction between atoms or molecules such as
van der Waals forces or polar attractions, including
hydrogen bonds.
Invertase
Enzyme which catalyses the conversion of sucrose to
glucose and fructose.
Ionic compounds
Compound formed between elements widely separated in
the periodic table.
Ionic lattice
A giant lattice structure of oppositely charged ions
electrostatically attracted to each other.
Mendeleev
Russian scientist who arranged elements in order of
increasing atomic masses in conjunction with similar
chemical properties, leaving gaps for yet to be
discovered elements.
Metallic bonding
Electrostatic attraction of a lattice of positively charged
ions and delocalised outer electrons.
Miscible
Can be mixed to form a homogeneous substance.
Molar volume
The volume occupied by 1 mole of a substance. It is the
same for all gases at the same temperature and
pressure.
Mole
The amount of a substance which contains as many
formula units as there are C atoms in 12g of carbon-12.
Monatomic
Discrete atoms held together by van der Waals’ forces.
Period
A row across the periodic table.
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Permanent diple-permanent
dipole interactions
Additional electrostatic forces of attraction between polar
molecules – stronger than van der Waals’ forces.
Photochemical reaction
Reaction in which light energy increases the number of
particles with energy greater than the activation energy.
Polar Bonds
Caused by a difference in electronegativity between
covalently bonded atoms. Atoms become partially
charged.
Polar molecules
Contain polar bonds which are not symmetrically
opposed. Molecule has a permanent dipole.
Polarity
The charge separation – depends on electronegativity
differences.
Rate
The change in concentration (or mass/volume) of
reactant or product in unit time (eg mols/l/s).
Reciprocal
The inverse of eg the reciprocal of t = 1/t.
Screening effect
Shielding of the outer electrons from the positive nuclear
charge by the inner shell electrons.
Specific heat capacity of
water (c)
Energy (kJ) required to raise the temperature of 1 Kg of
water 1oC.
Stoichiometry
Relative quantities of substances involved in reactions.
Sublimation
Change directly from a solid to a gas.
Substrate
The reactant which interacts with the catalyst in a
reaction.
Temperature
A measure of the average kinetic energy of the
molecules of a substance.
Van der Waals’ forces
Forces of attraction between atoms or molecules which
are much weaker than other forms of bonding. They
result from electrostatic attraction between temporary
dipoles caused by movement of electrons in atoms and
molecules. Bigger particles have stronger forces.
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UNIT 2
Addition polymers
THE WORLD OF CARBON
Made from unsaturated monomers by addition
polymerisation eg polythene (polyethene) from ethane.
Addition reaction
Addition of atoms or groups of atoms to alkenes by
opening up the double bond, eg hydrogenation,
bromination, hydration.
Alcohols
Substances containing the hydroxyl functional group.
Produced by catalytic hydration of alkenes or by
fermentation of carbohydrates.
Aldehydes
Group of substances containing –CHO group. Produced
by oxidation of primary alcohols eg using acidified
dichromate (yellow to blue colour change seen).
Oxidised to carboxylic acids using acidified dichromate or
Fehlings/Benedict’s (blue to red colour change seen).
Alkanals
A homologous series of alcohols based on the
corresponding parent alkanes.
Alkanones
A homologous series of ketones based on the
corresponding parent alkanes.
Alkenes
Hydrocarbons with general formula CnH2n and a carbon
to carbon double bond functional group.
Alkynes
Hydrocarbons with general formula CnH2n-2 and a carbon
to carbon triple bond functional group.
Aluminium oxide
Catalyst in cracking (not an oxidising agent).
Amide link
Formed by reaction of an amine group with a carboxyl
group. Also called a peptide link.
Amino
NH2 group present in amines and amides.
Amino acids
Monomers from which proteins are formed. Contain a
Carboxyl group and an amino group.
Anaerobic fermentation
Animal or vegetable matter decays in the absence of air
forming biogas.
Aromatics
Hydrocarbons containing a benzene ring. Produced from
coal or the naphtha fraction of oil. They improve the
efficiency of burning in petrol.
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Benedict’s solution
An oxidising agent containing Cu2+, used to oxidise
aldehydes to carboxylic acids.
Benzene
The simplest member of the class of aromatic
hydrocarbons, an important feedstock for a range of
consumer products eg drugs, dyes.
Biogas
Mixture of mainly methane (60%) and carbon dioxide,
which is a useful fuel in rural areas.
Biopol
An example of a biodegradable polymer.
Bromination
Addition reaction between bromine and unsaturated
hydrocarbons eg alkenes.
Carbonyl
CO group present in aldehydes, ketones, esters,
carboxylic acids.
Carboxyl group
COOH group in carboxylic acids.
Carboxylic acids
Substances containing –COOH (carboxyl) group. Formed
by oxidation of primary alcohols via aldehydes, using
acidified dichromate. Industrial production of ethanoic
acid is by direct oxidation of alkanes from oil or by
bacterial oxidation of ethanol from fermentation.
Identified by the ‘-oic’ name ending.
Catalytic hydration
Addition reaction where water adds onto an alkene
producing an alcohol. Used industrially to meet the
market demand for ethanol.
CFC’s
Halogenoalkanes which are thought to have been
responsible for depleting the ozone layer.
Chromatography
Separation technique for separating soluble components
of a mixture.
Condensation polymers
Made from monomers with 2 functional groups per
molecule eg nylon, a polyamide formed from a diamine
and a diacid, by condensation polymerisation.
Condensation reaction
Organic molecules combine with the removal of water.
Consumer products
Generally complex molecules which have been
synthesised from small reactive molecules, many of
which are organic.
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Covalent radius
Half the distance between the nuclei of two of its bonded
atoms.
Cracking
The breaking up of long chain hydrocarbons to produce
shorter chain alkanes which are in demand and small
unsaturated molecules which are feedstocks for plastics.
Cured polyester resins
Polyesters with a three dimensional structure.
Denatured
When the protein structure has been changed by high
temperatures on pH changes.
Diesel
Produced by blending gas oil fractions.
Digestion
The breakdown of food eg the hydrolysis of proteins to
form amino acids.
Electrolysis
Production of an element from a compound, either
molten or in solution, by passing electricity through it
eg production of hydrogen from water.
Enzymes
Biological catalysts. Some are wholly protein, others
require a co-enzyme to activate them. Sensitive to pH
and temperature.
Essential amino acids
Amino acids which are not produced in the body so have
to be present in dietary protein.
Ester link
Formed by reaction between a hydroxyl group and a
carboxyl group (-COO-)
Esters
Compounds formed by condensation reaction between
an alcohol and a carboxylic acid. Identified by ‘-COO-‘
functional group and ‘-oate’ name ending.
Ethene
Alkene formed by cracking ethane from natural gas or
cracking naphtha from crude oil distillation.
Ethyne
Common name acetylene. A hydrocarbon containing a
triple bond between the 2 carbon atoms C2H2.
Fats and oils
Mixtures of triglycerides formed by combination of 1
mole glycerol with 3 miles fatty acid. They are examples
of esters. They provide energy.
Fatty acids
Saturated or unsaturated straight chain carboxylic acids
with even number of C atoms from C4-C24, primarily C16
and C18.
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Feedstock
Enzyme catalysed process to produce ethanol from
carbohydrates.
Fibrous proteins
Long and thin and form the major structural materials of
living tissues.
Finite resource
A substance which is in limited supply and will run out.
Functional group
A group of atoms with characteristic chemical reactivity.
Globular proteins
Spiral chains folded into compact units. Involved in the
maintenance and regulation of life processes. Include
enzymes, many hormones eg insulin, and haemoglobin.
Glycerol
Propane- 1, 2, 3-triol, a trihydric alcohol.
Haloalkanes
See halogenoalkanes
Halides
Compounds containing a halogen.
Halogenoalkanes
Halogen substituted alkanes with properties which make
them useful in a variety of consumer products (see
CFC’s).
Hardening
A process for partially saturing oils by reacting with
hydrogen, using a nickel catalyst, to meet demands for
particular properties.
Hydrogen economy
Possible future use of hydrogen to store and distribute
energy.
Hydrogenation
Addition reaction between alkenes and hydrogen eg in
margarine production.
Hydrolysate
Mixture produced by hydrolysis.
Hydrolysis
Breaking down in the presence of water eg hydrolysis of
fats and oils to fatty acids and glycerol, or proteins to
amino acids.
Hydroxyl
OH group present in alcohols and carboxylic acids.
Ketones
Group of substances containing –CO group. Produced by
oxidation of secondary alcohols with acidified dichromate,
resistant to further oxidation.
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Kevlar
An aromatic polyamide which is extremely strong
because of the way in which its rigid, linear molecules
pack together. It has many important uses.
Knocking
Caused by auto-ignition of fuel in the engine.
Lipases
Enzymes which hydrolyse (‘digest’) fats and oils.
Liquefied petroleum gas
(LPG)
Methanal
Mixture of mainly propane and butane.
Methanol
Produced industrially from synthesis gas, used to make
methanal.
Miscrible
Applied to liquids which mix together (dissolve).
Naphtha
Fraction of crude oil used as a feedstock for alkenes by
cracking and for aromatics by reforming.
Natural gas
Mixture of mainly methane and ethane in varying
proportions.
Ninhydrin
Chemical used to show up the spots in chromatography.
Organic
Carbon containing compounds.
Oxidation
Reaction in which electrons are lost. It may happen
along with addition of oxygen or removal of hydrogen.
Ozone
O3 in the atmosphere forms a protective layer which
absorbs ultraviolet radiation from the sun.
Pepsin
Enzyme which hydrolyses proteins to amino acids.
Peptide link (=amide link)
The link between amino acids (‘-NHCO-‘). Formed by
reaction of an amine group with a carboxyl group.
Percentage yield
(Actual yield/theoretical yield) x 100.
Petrol
Produced by reforming naphtha. Any petrol is a blend of
hydrocarbons of different volatilities which takes account
of prevailing temperatures.
Phenyl
A benzene ring in which one hydrogen has been
substituted by another group of atoms – formula ‘C6H5-‘.
Alkanal used to produce thermosetting plastics.
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Photodegradable
Can be broken down by light eg low density polythene
can be modified during manufacture to produce a
photodegradable polymer.
Poly(ethanol)
A plastic which readily dissolves in water and has many
important uses. Made from a plastic by ester exchange.
Poly(vinyl carbozole)
Polymer exhibiting photoconductivity which is used in
photocopiers.
Polyamides
Examples of condensation polymers formed by reaction
of an amine group with a carboxyl group eg nylon.
Polyesters
Examples of condensation polymers formed by reaction
of a hydroxyl group with a carboxyl group. Used as
textile fibres and resins.
Polymeric esters
Used as textile fibres and resins – formed by
condensation polymerisation.
Primary
Functional group as at the end of the chain.
Propene
Alkene formed by cracking propane from natural gas or
cracking the naphtha fraction from oil.
Protein
Polymer formed by condensation polymerisation of amino
acids.
Reflux
To heat up (at boiling point) using a condenser to
prevent loss of vapour.
Reforming
A set of processes each of which alters the arrangement
of atoms in molecules without necessarily changing the
size eg conversion of straight chain hydrocarbons and
cyclic hydrocarbons in naphtha into branched chains and
aromatics, to improve the octane rating of petrol.
Renewable source
More can be made available eg sugar cane is a
renewable source of ethanol for engine fuel.
Saturated
Containing single C-C bonds.
Secondary
Functional group is not at a terminal position.
Soaps
Sodium or potassium salts of fatty acids. Produced by
the hydrolysis of fats and oils.
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Substrate
Reactant in an enzyme catalysed reaction.
Sugar cane
Used as a renewable source of enthanol.
Synthesis
To bulk up molecules from smaller simpler units.
Synthesis gas
Mixture of CO/H2/ Obtained by steam reforming of
methane from natural gas or steam reforming of coal.
Used to make methanol as feedstock for methanal.
Tertiary
Functional group is at a position where there is a branch
on the chain.
Triglyceride
Ester formed from condensation of 3 moles of fatty acid
with 1 mole of glycerol. The fatty acid groups may or
may not be identical.
Trihydric alcohol
An alcohol with 3 OH groups per molecule.
Tripeptide
Molecule formed from 3 amino acids joined together (not
part of a long polymer chain).
Unleaded petrol
The efficiency of burning is improved using branched
chain and/or aromatic hydrocarbons instead of lead
compounds.
Unsaturated
Containing multiple bonds eg C=C alkenes.
Volatile
Forms a vapour easily. Low B.Pt, but not necessarily
flammable.
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UNIT 3
Artificial sources
CHEMICAL REACTIONS
Made by bombarding stable nuclei with particles such as
neutrons in a nuclear reactor.
Batch process
A non-continuous manufacturing process.
By-product
A product of a manufacturing process which is produced
alongside the desired product.
Carbon dating
14
Compression
Increase in pressure.
Coulomb
Unit of charge.
Decay
Rearrangement of unstable to stable nuclei with emission
of energy. The decay is independent of the physical or
chemical state of the element.
Dynamic equilibrium
Reversible reactions attain a state of dynamic equilibrium
when the rates of forward and reverse reactions are
equal.
Electrolysis
Production of an element from a compound, either
molten or in solution, by passing electricity through it.
One mole of element requires nF coulombs (n=number
of electrons in the ion-electron equation, F=the Faraday).
Equilibrium
When the concentrations of reactants and products
remain constant although not necessarily equal.
Equimolar
Containing the same number of moles.
Faraday
The charge associated with 1 mole of electrons
(96500C).
Fission
Splitting some nuclei by bombarding them with slowmoving neutrons. Energy is emitted and more neutrons
are released leading to a self-sustaining chain reaction.
Fusion
Forming heavier nuclei by fusing together light nuclei
with the emission of large amounts of energy. Elements
are created in the stars from simple elements by nuclear
fusion.
C is used to date archaeological specimens. The ratio
of 14C / 12C is know for living things but the 14C decays
after death. The ratio for the specimen is measure and
the half life for 14C can be used to determine its age.
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Haber process
Industrial process to synthesise ammonia from nitrogen
and hydrogen using an iron catalyst.
Half-life (t1/2 )
The time taken for the activity of the isotope to decrease
by half. It is independent of the mass and is unaffected
by temperature, pressure, concentration, catalysts or the
physical or chemical state of the isotope.
Hess’s Law
∆H is independent of the route taken.
Intensity
The strength of – eg colour or light.
Isotopes
Atoms of the same element which differ in the number of
neutrons and hence the relative mass.
Labelling
Molecules can be labelled with radioisotopes to trace the
path of chemicals eg 32P in phosphate fertilisers to
observe the use of phosphate by growing plants.
Le Chatelier’s principle
If a system at equilibrium is subjected to any change, the
system readjusts itself to try and counteract the applied
change.
Nuclear fusion
See fusion.
Mass spectra
Output from a mass spectrometer which is used to
determine the mass numbers and relative proportions of
the various isotopes of an element.
Monoprotic acid
Containing one hydrogen in the formula eg HCl.
Oxidising agent
A substance which accepts electrons.
pH scale
A continuous range from below 0 to above 14 which is
related to the H+ concentration (pH = -log[H+]).
Pilot study
A stage in the manufacture of a new product. A small
scale industrial process is examined.
Radioactivity
A result of unstable nuclei rearranging to become more
stable by releasing energy.
Radioisotope
An unstable nucleus. Used in medicine, in industry, for
scientific research including carbon dating and to
produce energy by uranium fission and nuclear fusion.
Produced in igneous rocks which contain radioisotopes.
This is the greatest source of background radiation.
Radon
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Raw materials
Naturally occurring substances from which useful
materials can be separated or synthesised. The major
ones are fossil fuels, metallic ores and minerals, air and
water.
Redox equations
Combination of the ion electron equations involved in the
redox reaction.
Redox reaction
Reactions in which one reactant is oxidised (loses
electrons) while the other is reduced (gains electrons).
Redox titrations
Redox reaction carried out quantitatively where there is a
way of indicating the end point eg by a colour change.
See volumetric titration.
Reducing agent
A substance which donates electrons.
Relative atomic mass
The average value of the relative mass of all atoms of
the element. Mass is measured relative to the mass of
an atom of 12C.
Soaps
Salts of weak acids and strong bases (see unit 2).
Stoichiometry
Relative quantities of substances involved in reactions.
Strong acids (or bases)
Completely dissociated in solution.
Unstable nucleus
(=radioisotope)
A nucleus in which the proton/neutron ratio is outside
the region associated with stable nuclei.
Volumetric titration
Titration performed to calculate the concentration of a
reactant.
Weak acids (or bases)
Only partially dissociated in solution.
 particles
He nuclei, He2+, they can travel a few cm in air but are
absorbed by paper.
 particles
High energy electrons emitted form the nucleus when a
neutron changes into a proton and an electron. Can be
absorbed by thin aluminium.
 rays
High energy electromagnetic radiation (EMR) emitted
either alone or accompanying  or  particles. Thick lead
is required to absorb it.
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