A-LEVEL EDEXCEL CHEMISTRY PAPER 2
2025 With Questions And All Correct
Answers
Nucleophile - CORRECT ANSWER A species that donates a lone pair of electrons.
Examples include ammonia, water and cyanide.
Electrophile - CORRECT ANSWER A species that accepts a pair of electrons. The most
common example is H+ that accepts a lone pair of electrons from a nitrogen atom in
ammonia.
Nucleophilic substitution - CORRECT ANSWER A substitution reaction in which a
nucleophile such as ammonia is attracted to a positive charge centre such as the
functional group carbon atom of a halogenoalkane.
Hydrolysis - CORRECT ANSWER Breaking up a molecule using water. There are two
types of hydrolysis - acidic and alkaline
Ester - CORRECT ANSWER A molecule that contains the COO functional group. Many
esters are volatile and are found in fragrances such as rose oil.
Ester solubility in water - CORRECT ANSWER The middle of the molecule has had
hydrogen bonding between the oxygen of C=O and the H of water; and also between
the -O- and the H of water. The smaller the molecule the higher the solubility in water.
Ester solubility in hexane (non-polar solvent) - CORRECT ANSWER The non-polar alkyl
ends of the molecule form London forces with the solvent. The larger the molecule, the
greater the solubility in the hexane solvent because there are more London forces
between the solute molecule and the solvent molecule.
Ammonia - CORRECT ANSWER NH3
Primary amine - CORRECT ANSWER CH3NH2
Secondary amine - CORRECT ANSWER (CH3)2NH
Tertiary amine - CORRECT ANSWER (CH3)3N
Free radical substitution - CORRECT ANSWER When a halogen atom replaces a
hydrogen atom in a reaction. UV is required. At higher levels of the halogen, the amount
, of substitution increases. For example, CCL4 is formed at high CL2 levels, CH3Cl is
formed at low Cl2 levels. 3 steps I, P, T.
Electrophilic addition - CORRECT ANSWER A type of addition reaction in which an
electrophile is attracted to an electron-rich center or atom, where it accepts a pair of
electrons to form a new covalent bond.
Example - symbol equation - free radical substitution at low UV levels - CORRECT
ANSWER Cl2 + CH4 --> CH3Cl + HCl
Example - symbol equation - free radical substitution at high UV levels - CORRECT
ANSWER 4Cl2 + CH4 --> CCl4 + 4HCl
Example - symbol equation - electrophilic addition - CORRECT ANSWER C2H4 + Cl2 --
> C2H4Cl2
Example - symbol equation - addition polymerisation - CORRECT ANSWER n C2H4 -->
[C2H4]n
Structural isomerism - CORRECT ANSWER Atoms are joined in a different order
forming different structures
Stereoisomerism - CORRECT ANSWER Atoms are joined in the same order but they
occupy different positions in space
Optical isomerism - CORRECT ANSWER an example of stereoisomerism where the
molecule has one or more chiral centers
E/Z isomerism - CORRECT ANSWER an example of stereoisomerism where the
molecule has a double bond in the MIDDLE of the molecule for a hydrocarbon (e.g. but-
2-ene, not but-1-ene). Also known as 'geometric isomerism'.
Initiation - CORRECT ANSWER First step in free radical substitution
Propagation - CORRECT ANSWER Second step in free radical substitution
Termination - CORRECT ANSWER Final step in free radical substitution
Radical - CORRECT ANSWER A species that has an unpaired electron
Chlorine atom - CORRECT ANSWER Example of a radical
Homolytic fission - CORRECT ANSWER Type of bond breaking that forms two radicals
Heterolytic fission - CORRECT ANSWER Type of bond breaking that forms two
oppositely charged ions
2025 With Questions And All Correct
Answers
Nucleophile - CORRECT ANSWER A species that donates a lone pair of electrons.
Examples include ammonia, water and cyanide.
Electrophile - CORRECT ANSWER A species that accepts a pair of electrons. The most
common example is H+ that accepts a lone pair of electrons from a nitrogen atom in
ammonia.
Nucleophilic substitution - CORRECT ANSWER A substitution reaction in which a
nucleophile such as ammonia is attracted to a positive charge centre such as the
functional group carbon atom of a halogenoalkane.
Hydrolysis - CORRECT ANSWER Breaking up a molecule using water. There are two
types of hydrolysis - acidic and alkaline
Ester - CORRECT ANSWER A molecule that contains the COO functional group. Many
esters are volatile and are found in fragrances such as rose oil.
Ester solubility in water - CORRECT ANSWER The middle of the molecule has had
hydrogen bonding between the oxygen of C=O and the H of water; and also between
the -O- and the H of water. The smaller the molecule the higher the solubility in water.
Ester solubility in hexane (non-polar solvent) - CORRECT ANSWER The non-polar alkyl
ends of the molecule form London forces with the solvent. The larger the molecule, the
greater the solubility in the hexane solvent because there are more London forces
between the solute molecule and the solvent molecule.
Ammonia - CORRECT ANSWER NH3
Primary amine - CORRECT ANSWER CH3NH2
Secondary amine - CORRECT ANSWER (CH3)2NH
Tertiary amine - CORRECT ANSWER (CH3)3N
Free radical substitution - CORRECT ANSWER When a halogen atom replaces a
hydrogen atom in a reaction. UV is required. At higher levels of the halogen, the amount
, of substitution increases. For example, CCL4 is formed at high CL2 levels, CH3Cl is
formed at low Cl2 levels. 3 steps I, P, T.
Electrophilic addition - CORRECT ANSWER A type of addition reaction in which an
electrophile is attracted to an electron-rich center or atom, where it accepts a pair of
electrons to form a new covalent bond.
Example - symbol equation - free radical substitution at low UV levels - CORRECT
ANSWER Cl2 + CH4 --> CH3Cl + HCl
Example - symbol equation - free radical substitution at high UV levels - CORRECT
ANSWER 4Cl2 + CH4 --> CCl4 + 4HCl
Example - symbol equation - electrophilic addition - CORRECT ANSWER C2H4 + Cl2 --
> C2H4Cl2
Example - symbol equation - addition polymerisation - CORRECT ANSWER n C2H4 -->
[C2H4]n
Structural isomerism - CORRECT ANSWER Atoms are joined in a different order
forming different structures
Stereoisomerism - CORRECT ANSWER Atoms are joined in the same order but they
occupy different positions in space
Optical isomerism - CORRECT ANSWER an example of stereoisomerism where the
molecule has one or more chiral centers
E/Z isomerism - CORRECT ANSWER an example of stereoisomerism where the
molecule has a double bond in the MIDDLE of the molecule for a hydrocarbon (e.g. but-
2-ene, not but-1-ene). Also known as 'geometric isomerism'.
Initiation - CORRECT ANSWER First step in free radical substitution
Propagation - CORRECT ANSWER Second step in free radical substitution
Termination - CORRECT ANSWER Final step in free radical substitution
Radical - CORRECT ANSWER A species that has an unpaired electron
Chlorine atom - CORRECT ANSWER Example of a radical
Homolytic fission - CORRECT ANSWER Type of bond breaking that forms two radicals
Heterolytic fission - CORRECT ANSWER Type of bond breaking that forms two
oppositely charged ions
