AQA GCSE COMBINED SCIENCE: TRILOGY
8464/C/2H HIGHER TIER CHEMISTRY
PAPER 2H PAPER & MARK SCHEME
COMPREHENSIVE STUDY GUIDE 2026 FULL
QUESTIONS AND SOLUTIONS GRADED A+
◍ equilibrium.
Answer: both reactions are happening but there is no overall
effectunchanging balance of products and reactantsonly occurs in a closed
system, reactions are happening at the same rate
◍ carbon monoxide.
Answer: A poisonous gas produced during incomplete combustion, a silent
killer.
◍ Measuring rate of reaction - Change in mass.
Answer: - Put reaction on a measuring scale- If a gas is produced, the mass
will decrease- The quicker the mass decreases, the faster the reaction
◍ collision theory in rate of reaction.
Answer: 1. collision frequency of reacting particlesmore collisions = faster
rate2. For energy to be transferred during a reactionparticles need to collide
with enough energy to make the reaction successful
◍ chromatography.
Answer: the process whereby small amounts of dissolved substances are
separated by running a solvent along a material such as absorbent paper
◍ mixture.
Answer: A substance containing two or more elements or compounds that
, are mixed but not joined together.
◍ What are examples of surface water sources.
Answer: Lakes, rivers, reservoirs
◍ Complete combustion.
Answer: - During combustion both the hydrogen and the carbon are
oxidised.- Hydrocarbons are used as fuels due to the amount of energy
releases after the completion of combustion
◍ What do flame tests and precipitation reactions test for?.
Answer: Positive ions
◍ Magnesium and HCl react to produce H2 gas.
Answer: 1. Add a set volume of dilute HCL to a conical flask and place on
mass balance.2. Add a magnesium ribbon to acid and quickly plug the flask
with cotton wool.3. Start stopwatch and record mass of balance at regular
intervals.4. Plot results in a table and work out mass lost for each reading ->
plot results on a graph.5. Repeat with more concentrated acid solutions.
(Keep control variables like volume of acid and amount of magnesium
ribbon same each time)
◍ alkane.
Answer: A hydrocarbon containing only single bonds.
◍ Why are reverse osmosis and distillation impractical for producing large
amounts of water.
Answer: They both use loads of energy, so very expensive
◍ Properties of hydrocarbons depend on the length of the chain. The longer the
hydrocarbon chain...(4).
Answer: the more viscous it is (thick)the less volatile it is (evaporates more
easily and quickly) - low boiling pointsthe less flammable it ishigher the
boiling points (more intermolecular forces)
◍ 2 examples of long hydrocarbons in crude oil.
Answer: Bitumen - used to surface roadsHeavy fuel oil - can be separated
, further and used as fuel, for heating, or as lubricant.
◍ Properties of alkenes.
Answer: - Unsaturated- c=c bond can open to bond to other atoms- much
more reactive than alkanes
◍ First 3 Alkenes.
Answer: ethene C2H4propene C3H6butene C4H8
◍ What is domestic water waste, where does it go.
Answer: Household waste; from showers, sinks and toilets.Goes into sewers
and to the sewage treatment plants
◍ Why is cracking important.
Answer: Breaks down large, heavy hydrocarbon molecules into smaller,
higher value products like petrol (gasoline) and alkenes.
◍ complete combustion.
Answer: When a fuel burns in plenty of oxygen to produce only carbon
dioxide and water.
◍ rate of reversible reactions.
Answer: as reactants react, their concentration falls. (forward reaction
slows)as products are made, their concentration rises(backward reaction
speeds up)eventually forward reaction is at same rate as backward reaction
(equilibrium)
◍ flammability.
Answer: How easily a substance will burn.
◍ formulations.
Answer: a mixture designed to produce a useful product
◍ burning fossil fuels.
Answer: releases more CO2
◍ hydrocarbon.
Answer: A compound that contains hydrogen and carbon only.
8464/C/2H HIGHER TIER CHEMISTRY
PAPER 2H PAPER & MARK SCHEME
COMPREHENSIVE STUDY GUIDE 2026 FULL
QUESTIONS AND SOLUTIONS GRADED A+
◍ equilibrium.
Answer: both reactions are happening but there is no overall
effectunchanging balance of products and reactantsonly occurs in a closed
system, reactions are happening at the same rate
◍ carbon monoxide.
Answer: A poisonous gas produced during incomplete combustion, a silent
killer.
◍ Measuring rate of reaction - Change in mass.
Answer: - Put reaction on a measuring scale- If a gas is produced, the mass
will decrease- The quicker the mass decreases, the faster the reaction
◍ collision theory in rate of reaction.
Answer: 1. collision frequency of reacting particlesmore collisions = faster
rate2. For energy to be transferred during a reactionparticles need to collide
with enough energy to make the reaction successful
◍ chromatography.
Answer: the process whereby small amounts of dissolved substances are
separated by running a solvent along a material such as absorbent paper
◍ mixture.
Answer: A substance containing two or more elements or compounds that
, are mixed but not joined together.
◍ What are examples of surface water sources.
Answer: Lakes, rivers, reservoirs
◍ Complete combustion.
Answer: - During combustion both the hydrogen and the carbon are
oxidised.- Hydrocarbons are used as fuels due to the amount of energy
releases after the completion of combustion
◍ What do flame tests and precipitation reactions test for?.
Answer: Positive ions
◍ Magnesium and HCl react to produce H2 gas.
Answer: 1. Add a set volume of dilute HCL to a conical flask and place on
mass balance.2. Add a magnesium ribbon to acid and quickly plug the flask
with cotton wool.3. Start stopwatch and record mass of balance at regular
intervals.4. Plot results in a table and work out mass lost for each reading ->
plot results on a graph.5. Repeat with more concentrated acid solutions.
(Keep control variables like volume of acid and amount of magnesium
ribbon same each time)
◍ alkane.
Answer: A hydrocarbon containing only single bonds.
◍ Why are reverse osmosis and distillation impractical for producing large
amounts of water.
Answer: They both use loads of energy, so very expensive
◍ Properties of hydrocarbons depend on the length of the chain. The longer the
hydrocarbon chain...(4).
Answer: the more viscous it is (thick)the less volatile it is (evaporates more
easily and quickly) - low boiling pointsthe less flammable it ishigher the
boiling points (more intermolecular forces)
◍ 2 examples of long hydrocarbons in crude oil.
Answer: Bitumen - used to surface roadsHeavy fuel oil - can be separated
, further and used as fuel, for heating, or as lubricant.
◍ Properties of alkenes.
Answer: - Unsaturated- c=c bond can open to bond to other atoms- much
more reactive than alkanes
◍ First 3 Alkenes.
Answer: ethene C2H4propene C3H6butene C4H8
◍ What is domestic water waste, where does it go.
Answer: Household waste; from showers, sinks and toilets.Goes into sewers
and to the sewage treatment plants
◍ Why is cracking important.
Answer: Breaks down large, heavy hydrocarbon molecules into smaller,
higher value products like petrol (gasoline) and alkenes.
◍ complete combustion.
Answer: When a fuel burns in plenty of oxygen to produce only carbon
dioxide and water.
◍ rate of reversible reactions.
Answer: as reactants react, their concentration falls. (forward reaction
slows)as products are made, their concentration rises(backward reaction
speeds up)eventually forward reaction is at same rate as backward reaction
(equilibrium)
◍ flammability.
Answer: How easily a substance will burn.
◍ formulations.
Answer: a mixture designed to produce a useful product
◍ burning fossil fuels.
Answer: releases more CO2
◍ hydrocarbon.
Answer: A compound that contains hydrogen and carbon only.
