6/19/25, 5:16 AM OCR A-Level Chemistry
OCR A-Level Chemistry COMPLETE
QUESTIONS AND CORRECT DETAILED
ANSWERS \VERIFIED ANSWERS ALREADY
GRADED A+
Acid A species that releases H+ ions in aqueous solution
The equilibrium constant that
Acid Dissociation shows the extent of dissociation
Constant Ka of a weak acid
A pair of two species that transform into each other
Acid-Base Pair
by gain or loss of a proton
The minimum energy required to start a reaction by
Activation Energy
the breaking of bonds
Actual Yield The amount of product obtained from a reaction
Formation of a very long molecular chain, by
Addition Polymerisation repeated addition reactions of many unsaturated
alkene molecules (monomers).
A reaction in which a reactant is added to an
Addition Reaction unsaturated molecule to make a one saturated
molecule
The process that occurs when a gas or liquid or solute
Adsorption
is held to the surface of a solid.
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,6/19/25, 5:16 AM OCR A-Level Chemistry
Containing carbon atoms joined together in a ring
Alicyclic
that is not aromatic
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, 6/19/25, 5:16 AM OCR A-Level Chemistry
Containing carbon atoms joined together in straight
Aliphatic
or branched chains.
A type of base that dissolves in water forming
Alkali
hydroxide ions, OH- (aq) ions.
The hydrocarbon homologous series with single
Alkanes carbon-to-carbon bonds
and the general formula: CnH2n+2.
The hydrocarbon homologous series with at one
Alkenes double carbon-to-carbon
bonds and the general formula: CnH2n.
A side chain formed by removing a hydrogen atom
removed from an
Alkyl Group alkane parent chain, for example, CH3, C2H5; any
alkyl group is often shown
as R.
The hydrocarbon homologous series with one triple
Alkynes carbon-to-carbon bonds and the general formula:
CnH2n-2.
The quantity whose unit of the mole, used as a means
Amount of Substance of counting any species such as atoms, ions and
molecules.
Anhydrous Containing no water molecules
A negatively charged ion with more electrons than
Anion
protons
Aromatic Containing one or more benzene rings
((sum of molar masses of desired products)/(sum of
Atom Economy
molar masses of all products)) x 100%.
Atomic (Proton) Number The number of protons in the nucleus of an atom
A region around the nucleus that can hold up to two
Atomic Orbital
electrons with opposite spins
3/19
OCR A-Level Chemistry COMPLETE
QUESTIONS AND CORRECT DETAILED
ANSWERS \VERIFIED ANSWERS ALREADY
GRADED A+
Acid A species that releases H+ ions in aqueous solution
The equilibrium constant that
Acid Dissociation shows the extent of dissociation
Constant Ka of a weak acid
A pair of two species that transform into each other
Acid-Base Pair
by gain or loss of a proton
The minimum energy required to start a reaction by
Activation Energy
the breaking of bonds
Actual Yield The amount of product obtained from a reaction
Formation of a very long molecular chain, by
Addition Polymerisation repeated addition reactions of many unsaturated
alkene molecules (monomers).
A reaction in which a reactant is added to an
Addition Reaction unsaturated molecule to make a one saturated
molecule
The process that occurs when a gas or liquid or solute
Adsorption
is held to the surface of a solid.
1/19
,6/19/25, 5:16 AM OCR A-Level Chemistry
Containing carbon atoms joined together in a ring
Alicyclic
that is not aromatic
2/19
, 6/19/25, 5:16 AM OCR A-Level Chemistry
Containing carbon atoms joined together in straight
Aliphatic
or branched chains.
A type of base that dissolves in water forming
Alkali
hydroxide ions, OH- (aq) ions.
The hydrocarbon homologous series with single
Alkanes carbon-to-carbon bonds
and the general formula: CnH2n+2.
The hydrocarbon homologous series with at one
Alkenes double carbon-to-carbon
bonds and the general formula: CnH2n.
A side chain formed by removing a hydrogen atom
removed from an
Alkyl Group alkane parent chain, for example, CH3, C2H5; any
alkyl group is often shown
as R.
The hydrocarbon homologous series with one triple
Alkynes carbon-to-carbon bonds and the general formula:
CnH2n-2.
The quantity whose unit of the mole, used as a means
Amount of Substance of counting any species such as atoms, ions and
molecules.
Anhydrous Containing no water molecules
A negatively charged ion with more electrons than
Anion
protons
Aromatic Containing one or more benzene rings
((sum of molar masses of desired products)/(sum of
Atom Economy
molar masses of all products)) x 100%.
Atomic (Proton) Number The number of protons in the nucleus of an atom
A region around the nucleus that can hold up to two
Atomic Orbital
electrons with opposite spins
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