2026 AQA A LEVEL CHEMISTRY PAPER 2
UPDATED ACTUAL EXAM QUESTIONS AND
CORRECT ANSWERS FULL SOLUTION
GRADED A+
◉ Relative atomic mass (Ar). Answer: Average mass of an atom
compared with one twelth of the mass of an atom of carbon 12
◉ Electronegativity. Answer: Power of an atom to attract the pair of
electrons in a covalent bond
◉ Standard enthalpy of combustion. Answer: Enthalpy change when
1 mole of a substance burns completely in oxygen under standard
conditions with all reactants and products being in their standard state
◉ Standard enthalpy of formation. Answer: Enthalpy change when 1
mole of a compound is formed from it's elements under standard
conditions in their standard states
◉ Mean bond enthalpy. Answer: The average energy needed to break
a certain type of bond over a range of compounds
◉ Activation energy. Answer: Minimum energy required for colliding
molecules to react
,◉ Maxwell-Boltzmann distribution x and y axes. Answer: x: Energy
y: fraction/number of molecules
◉ What happens to the Maxwell-Boltzmann curve when temperature
increases. Answer: Moves down and to the right
◉ Rate of reaction. Answer: Rate at which product formed/reactant
used up
◉ Order of reaction. Answer: Power to which the concentration of a
species is raised in the rate equation
◉ rearrange k=Ae^-Ea/Rt. Answer: lnk=-Ea/Rt+lnA
◉ Conditions for thermal cracking. Answer: High temperature and
high pressure
◉ Products of thermal cracking. Answer: High % of alkenes
◉ Conditions for catalytic cracking. Answer: High temperature ,slight
pressure and in the presence of a zeolite catalyst
◉ Products of catalytic cracking. Answer: Motor fuels and aromatic
hydrocarbons
, ◉ Why do we crack alkanes?. Answer: Smaller alkanes/alkenes
generally more useful than longer chain ones
◉ Equation for complete combustion of alkanes. Answer: alkane +
oxygen > carbon dioxide + water
◉ Equations for incomplete combustion of alkanes. Answer: alkane +
oxygen > carbon monoxide/carbon + water
◉ Pollutants produced by combustion engines. Answer: NOx, CO, C
and sunburned hydrocarbons
◉ Reaction of methane with chlorine. Answer: I: Cl2 > 2Cl•
P: CH4 + Cl• > CH3• + Chi
CH3• + Cl2 > CH3Cl + Cl•
T: CH3• + Cl• > CH3Cl
◉ 2 equations showing decomposition of the ozone. Answer: Cl• +
O3 > ClO• + O2
ClO• + O3 > 2O2 + Cl•
◉ What types of mechanism do haloalkanes undergo?. Answer: -
Nucleophilic substitution by aqueous hydroxide ions, cyanide ions or
ammonia
UPDATED ACTUAL EXAM QUESTIONS AND
CORRECT ANSWERS FULL SOLUTION
GRADED A+
◉ Relative atomic mass (Ar). Answer: Average mass of an atom
compared with one twelth of the mass of an atom of carbon 12
◉ Electronegativity. Answer: Power of an atom to attract the pair of
electrons in a covalent bond
◉ Standard enthalpy of combustion. Answer: Enthalpy change when
1 mole of a substance burns completely in oxygen under standard
conditions with all reactants and products being in their standard state
◉ Standard enthalpy of formation. Answer: Enthalpy change when 1
mole of a compound is formed from it's elements under standard
conditions in their standard states
◉ Mean bond enthalpy. Answer: The average energy needed to break
a certain type of bond over a range of compounds
◉ Activation energy. Answer: Minimum energy required for colliding
molecules to react
,◉ Maxwell-Boltzmann distribution x and y axes. Answer: x: Energy
y: fraction/number of molecules
◉ What happens to the Maxwell-Boltzmann curve when temperature
increases. Answer: Moves down and to the right
◉ Rate of reaction. Answer: Rate at which product formed/reactant
used up
◉ Order of reaction. Answer: Power to which the concentration of a
species is raised in the rate equation
◉ rearrange k=Ae^-Ea/Rt. Answer: lnk=-Ea/Rt+lnA
◉ Conditions for thermal cracking. Answer: High temperature and
high pressure
◉ Products of thermal cracking. Answer: High % of alkenes
◉ Conditions for catalytic cracking. Answer: High temperature ,slight
pressure and in the presence of a zeolite catalyst
◉ Products of catalytic cracking. Answer: Motor fuels and aromatic
hydrocarbons
, ◉ Why do we crack alkanes?. Answer: Smaller alkanes/alkenes
generally more useful than longer chain ones
◉ Equation for complete combustion of alkanes. Answer: alkane +
oxygen > carbon dioxide + water
◉ Equations for incomplete combustion of alkanes. Answer: alkane +
oxygen > carbon monoxide/carbon + water
◉ Pollutants produced by combustion engines. Answer: NOx, CO, C
and sunburned hydrocarbons
◉ Reaction of methane with chlorine. Answer: I: Cl2 > 2Cl•
P: CH4 + Cl• > CH3• + Chi
CH3• + Cl2 > CH3Cl + Cl•
T: CH3• + Cl• > CH3Cl
◉ 2 equations showing decomposition of the ozone. Answer: Cl• +
O3 > ClO• + O2
ClO• + O3 > 2O2 + Cl•
◉ What types of mechanism do haloalkanes undergo?. Answer: -
Nucleophilic substitution by aqueous hydroxide ions, cyanide ions or
ammonia
