2025 AQA GCSE CHEMISTRY 8462/1H
HIGHER TIER PAPER QUESTION
PAPER & MARKING SCHEME
COMBINED 2025 VERIFIED
Soluble salt formation - answers Soluble salts form from metal oxide reactions with
acids.
Calcium nitrate formula - answers Calcium nitrate's formula, containing Ca2+ and NO3-,
is Ca(NO3)2.
Magnesium sulfate crystals method - answers React metal oxide with dilute acid, filter,
evaporate, and dry.
Iron pyrites formula - answers The formula of iron pyrites, determined from its structure,
is FeS2.
Iron atom protons - answers An iron atom (Fe) has 26 protons.
Iron atom neutrons - answers An iron atom (Fe) has 30 neutrons.
Iron atom electrons - answers An iron atom (Fe) has 26 electrons.
Transition metal properties - answers Transition metals have higher melting points and
densities than Group 1.
Carbon in nickel extraction - answers Carbon extracts nickel from nickel oxide because
it's more reactive.
Atom economy definition - answers Atom economy is the percentage of reactants
becoming useful products.
Atom economy formula - answers Atom Economy = (Mr of desired product / Mr of all
reactants) x 100
Simple cell voltmeter reading - answers Identical electrodes in the same electrolyte yield
a zero reading.
Alkaline battery depletion - answers Alkaline batteries stop when reactants are used up.
Non-rechargeable battery reason - answers Alkaline batteries cannot be reversed; the
reaction is irreversible.
,Acid reaction for soluble salt - answers Acids react with metal carbonates to form
soluble salts.
Metal oxide reaction - answers Metal oxides react with acids to form soluble salts and
water.
Crystallization process - answers Crystallization involves evaporating a solution to form
pure crystals.
Ionic compound definition - answers Ionic compounds are formed through electrostatic
attraction of ions.
Reduction reaction - answers Reduction is the gain of electrons by a substance.
Electrolyte definition - answers An electrolyte is a substance that conducts electricity
when dissolved.
Rechargeable battery - answers Rechargeable batteries can reverse chemical reactions
to recharge.
Iron vs. Sodium - answers Iron is harder and has a higher melting point than sodium.
Hydrogen fuel cell reaction - answers 2H2 + O2 -> 2H2O, hydrogen reacts with oxygen
to produce water.
Hydrogen fuel cell refueling time - answers Approximately 5 minutes, according to the
table provided.
Lithium-ion battery recharge time - answers Approximately 30 minutes, according to the
table provided.
Hydrogen fuel cell distance - answers Up to 415 miles before refueling, according to the
table.
Lithium-ion battery distance - answers Up to 240 miles before recharging, according to
the table.
Hydrogen fuel cell energy efficiency - answers Travels 22 km per unit of energy,
according to the table.
Lithium-ion battery energy efficiency - answers Travels 66 km per unit of energy,
according to the table.
Hydrogen fuel cell cost - answers £50 to refuel, according to the table provided.
, Lithium-ion battery cost - answers £3 to recharge, according to the table provided.
Hydrogen fuel cell car cost - answers Minimum cost of car is £60,000, according to the
table.
Lithium-ion battery car cost - answers Minimum cost of car is £18,000, according to the
table.
Plum pudding model - answers An outdated atomic model with electrons in positive
'pudding'.
Alpha particle scattering experiment - answers Led to the discovery of the nucleus in the
atom.
Bohr's atomic model - answers Model with electrons orbiting the nucleus at specific
energy levels.
Mass number - answers The total number of protons and neutrons in an atom's nucleus.
Isotopes - answers Atoms of the same element with different numbers of neutrons.
Chadwick's work - answers Discovery of the neutron, explaining isotopes' different
masses.
Exothermic reaction - answers A reaction that releases heat, causing a temperature
increase.
Reactivity series - answers Lists metals by reactivity, used to predict displacement
reactions.
Displacement reaction - answers A reaction where a more reactive metal replaces a
less reactive one.
Reaction profile - answers Diagram showing energy changes during a chemical
reaction.
Endothermic reaction - answers A reaction that absorbs heat, causing a temperature
decrease.
Electrolysis - answers The process using electricity to break down a compound.
Graphite's conductivity - answers Each carbon atom forms three covalent bonds,
leaving delocalized electrons.
Electrolysis apparatus error - answers Use an inverted measuring cylinder to collect
gases.
HIGHER TIER PAPER QUESTION
PAPER & MARKING SCHEME
COMBINED 2025 VERIFIED
Soluble salt formation - answers Soluble salts form from metal oxide reactions with
acids.
Calcium nitrate formula - answers Calcium nitrate's formula, containing Ca2+ and NO3-,
is Ca(NO3)2.
Magnesium sulfate crystals method - answers React metal oxide with dilute acid, filter,
evaporate, and dry.
Iron pyrites formula - answers The formula of iron pyrites, determined from its structure,
is FeS2.
Iron atom protons - answers An iron atom (Fe) has 26 protons.
Iron atom neutrons - answers An iron atom (Fe) has 30 neutrons.
Iron atom electrons - answers An iron atom (Fe) has 26 electrons.
Transition metal properties - answers Transition metals have higher melting points and
densities than Group 1.
Carbon in nickel extraction - answers Carbon extracts nickel from nickel oxide because
it's more reactive.
Atom economy definition - answers Atom economy is the percentage of reactants
becoming useful products.
Atom economy formula - answers Atom Economy = (Mr of desired product / Mr of all
reactants) x 100
Simple cell voltmeter reading - answers Identical electrodes in the same electrolyte yield
a zero reading.
Alkaline battery depletion - answers Alkaline batteries stop when reactants are used up.
Non-rechargeable battery reason - answers Alkaline batteries cannot be reversed; the
reaction is irreversible.
,Acid reaction for soluble salt - answers Acids react with metal carbonates to form
soluble salts.
Metal oxide reaction - answers Metal oxides react with acids to form soluble salts and
water.
Crystallization process - answers Crystallization involves evaporating a solution to form
pure crystals.
Ionic compound definition - answers Ionic compounds are formed through electrostatic
attraction of ions.
Reduction reaction - answers Reduction is the gain of electrons by a substance.
Electrolyte definition - answers An electrolyte is a substance that conducts electricity
when dissolved.
Rechargeable battery - answers Rechargeable batteries can reverse chemical reactions
to recharge.
Iron vs. Sodium - answers Iron is harder and has a higher melting point than sodium.
Hydrogen fuel cell reaction - answers 2H2 + O2 -> 2H2O, hydrogen reacts with oxygen
to produce water.
Hydrogen fuel cell refueling time - answers Approximately 5 minutes, according to the
table provided.
Lithium-ion battery recharge time - answers Approximately 30 minutes, according to the
table provided.
Hydrogen fuel cell distance - answers Up to 415 miles before refueling, according to the
table.
Lithium-ion battery distance - answers Up to 240 miles before recharging, according to
the table.
Hydrogen fuel cell energy efficiency - answers Travels 22 km per unit of energy,
according to the table.
Lithium-ion battery energy efficiency - answers Travels 66 km per unit of energy,
according to the table.
Hydrogen fuel cell cost - answers £50 to refuel, according to the table provided.
, Lithium-ion battery cost - answers £3 to recharge, according to the table provided.
Hydrogen fuel cell car cost - answers Minimum cost of car is £60,000, according to the
table.
Lithium-ion battery car cost - answers Minimum cost of car is £18,000, according to the
table.
Plum pudding model - answers An outdated atomic model with electrons in positive
'pudding'.
Alpha particle scattering experiment - answers Led to the discovery of the nucleus in the
atom.
Bohr's atomic model - answers Model with electrons orbiting the nucleus at specific
energy levels.
Mass number - answers The total number of protons and neutrons in an atom's nucleus.
Isotopes - answers Atoms of the same element with different numbers of neutrons.
Chadwick's work - answers Discovery of the neutron, explaining isotopes' different
masses.
Exothermic reaction - answers A reaction that releases heat, causing a temperature
increase.
Reactivity series - answers Lists metals by reactivity, used to predict displacement
reactions.
Displacement reaction - answers A reaction where a more reactive metal replaces a
less reactive one.
Reaction profile - answers Diagram showing energy changes during a chemical
reaction.
Endothermic reaction - answers A reaction that absorbs heat, causing a temperature
decrease.
Electrolysis - answers The process using electricity to break down a compound.
Graphite's conductivity - answers Each carbon atom forms three covalent bonds,
leaving delocalized electrons.
Electrolysis apparatus error - answers Use an inverted measuring cylinder to collect
gases.
