GCSE CHEMISTRY EXAM REVISION. QUESTIONS WITH VERIFIED
SOLUTIONS LATEST 2025 UPDATE.
State the raw materials used in the manufacture of sulfuric acid. (Triple science only!) - ANSWER-
sulphur (from ores)
oxygen (from air)
Describe the manufacture of sulfuric acid by the contact process. (Triple science only!) -
ANSWER- 1) Making of sulfur dioxide: S + O₂ → SO₂
2) Reversible step: 2SO₂ + O₂ → 2SO₃ (exothermic)
3) H₂SO₄ + SO₃ → H₂S₂O₇
4) H₂S₂O₇ + H₂O → 2H₂SO₄
State the temperature used for the manufacture of sulfuric acid by the contact process. (Triple
science only!) - ANSWER- 450°C
State the pressure used for the manufacture of sulfuric acid by the contact process. (Triple science
only!) - ANSWER- 2 atm
State the catalyst used for the manufacture of sulfuric acid by the contact process. (Triple science
only!) - ANSWER- Vanadium(V) oxide
State the uses of sulfuric acid. (Triple science only!) - ANSWER- manufacture of detergents,
fertilisers and paints
In the electrolysis of NaCl, what are the anode and cathode made of? (Triple science only!) -
ANSWER- anode = titanium
cathode = iron
,State the name of the gas formed at the anode during the electrolysis sodium chloride solution.
(Triple science only!) - ANSWER- chlorine
State the name of the gas formed at the cathode during the electrolysis sodium chloride solution.
(Triple science only!) - ANSWER- hydrogen
The solution formed after the electrolysis sodium chloride solution was tested with the indicator
phenolphthalein. The indicator turned pink. Explain this result. (Triple science only!) - ANSWER-
The solution is alkali (contains sodium hydroxide)
In the electrolysis of brine, why is thelectrode made out of titanium? (Triple science only!) -
ANSWER- To prevent it reacting with the chlorine
Write the two ionic half-equations for the reactions that occur during the electrolysis of sodium
chloride solution. (Triple science only!) - ANSWER- 2H⁺ + 2e⁻ → H₂
2Cl⁻ → Cl₂ + 2e⁻
Temperatures effect on the rate of reaction - ANSWER- Increasing the temperature will cause
particles to move faster and with more energy, they will therefore collide more often and with
greater energy
-More collisions
-More energy
Concentrations effect on the rate of reaction - ANSWER- Increasing the concentration
increases the amount of reactant particles which may collide and so react
-More collisions
Surface areas effect on the rate of reaction - ANSWER- A higher surface area means a greater
area of reactant is exposed and available for collision
-More collision
,A catalysts effect on the rate of reaction - ANSWER- Presence of a catalyst reduces the amount
of activation energy needed for a reaction to take palce
-Less energy needed
How to measure the speed of reaction - ANSWER- You can measure
-Speed at which reactants are being used up
-Speed at which products are being formed
How to measure the speed of reaction when a gas is produced - ANSWER- Gas syringe
Explosions in a chemical reaction - ANSWER- Explosions occurs when a chemical reaction
suddenly accelerates and goes at an extremely fast rate
-Reaction gives of a lot of heat which heats up the reactants making the reaction go even faster
-No opportunity for the heat of reaction to escape or for the reactants to move away
-Occurs if the gas/powder is flammable
Oxidation - ANSWER- -Gain of oxygen by an atom, molecule or ion
-Loss of electron from an atom, molecule or ion
What do oxidising agents do - ANSWER- -Give oxygen
-Remove electron
Reduction - ANSWER- -Removal of oxygen in a compound
-Gain of electrons from an atom molecule or ion
What do reducing agents do - ANSWER- -Remove oxygen
, -Donate electrons
Redox reaction - ANSWER- Reaction which involves both oxidation and reduction
-Oil rig happen simultaneously
eg. When a metal oxide is being displaced
-Electrolysis
State the raw materials used in the manufacture of ammonia - ANSWER- nitrogen from air
hydrogen from natural gas
State a use for N₂ - ANSWER- making ammonia
The following reaction is used to manufacture ammonia in the Haber process
N₂ + 3H₂ → 2NH₃ ΔH = -92KJ/mol
The reaction is carried out at 450°C but the reaction would be faster if a higher temperature were
used.
Suggest why a higher temperature is not used in the Haber process - ANSWER- Yield would
decrease and energy costs would increase
State the temperature used for the manufacture of ammonia by the Haber process - ANSWER-
450°C
State the pressure used for the manufacture of ammonia by the Haber process - ANSWER- 200
atm
State the catalyst used for the manufacture of ammonia by the Haber process - ANSWER- Iron
How is ammonia separated from unreacted hydrogen and nitrogen in the Haber process? -
ANSWER- The reaction mixture is cooled until the ammonia condenses into a liquid
SOLUTIONS LATEST 2025 UPDATE.
State the raw materials used in the manufacture of sulfuric acid. (Triple science only!) - ANSWER-
sulphur (from ores)
oxygen (from air)
Describe the manufacture of sulfuric acid by the contact process. (Triple science only!) -
ANSWER- 1) Making of sulfur dioxide: S + O₂ → SO₂
2) Reversible step: 2SO₂ + O₂ → 2SO₃ (exothermic)
3) H₂SO₄ + SO₃ → H₂S₂O₇
4) H₂S₂O₇ + H₂O → 2H₂SO₄
State the temperature used for the manufacture of sulfuric acid by the contact process. (Triple
science only!) - ANSWER- 450°C
State the pressure used for the manufacture of sulfuric acid by the contact process. (Triple science
only!) - ANSWER- 2 atm
State the catalyst used for the manufacture of sulfuric acid by the contact process. (Triple science
only!) - ANSWER- Vanadium(V) oxide
State the uses of sulfuric acid. (Triple science only!) - ANSWER- manufacture of detergents,
fertilisers and paints
In the electrolysis of NaCl, what are the anode and cathode made of? (Triple science only!) -
ANSWER- anode = titanium
cathode = iron
,State the name of the gas formed at the anode during the electrolysis sodium chloride solution.
(Triple science only!) - ANSWER- chlorine
State the name of the gas formed at the cathode during the electrolysis sodium chloride solution.
(Triple science only!) - ANSWER- hydrogen
The solution formed after the electrolysis sodium chloride solution was tested with the indicator
phenolphthalein. The indicator turned pink. Explain this result. (Triple science only!) - ANSWER-
The solution is alkali (contains sodium hydroxide)
In the electrolysis of brine, why is thelectrode made out of titanium? (Triple science only!) -
ANSWER- To prevent it reacting with the chlorine
Write the two ionic half-equations for the reactions that occur during the electrolysis of sodium
chloride solution. (Triple science only!) - ANSWER- 2H⁺ + 2e⁻ → H₂
2Cl⁻ → Cl₂ + 2e⁻
Temperatures effect on the rate of reaction - ANSWER- Increasing the temperature will cause
particles to move faster and with more energy, they will therefore collide more often and with
greater energy
-More collisions
-More energy
Concentrations effect on the rate of reaction - ANSWER- Increasing the concentration
increases the amount of reactant particles which may collide and so react
-More collisions
Surface areas effect on the rate of reaction - ANSWER- A higher surface area means a greater
area of reactant is exposed and available for collision
-More collision
,A catalysts effect on the rate of reaction - ANSWER- Presence of a catalyst reduces the amount
of activation energy needed for a reaction to take palce
-Less energy needed
How to measure the speed of reaction - ANSWER- You can measure
-Speed at which reactants are being used up
-Speed at which products are being formed
How to measure the speed of reaction when a gas is produced - ANSWER- Gas syringe
Explosions in a chemical reaction - ANSWER- Explosions occurs when a chemical reaction
suddenly accelerates and goes at an extremely fast rate
-Reaction gives of a lot of heat which heats up the reactants making the reaction go even faster
-No opportunity for the heat of reaction to escape or for the reactants to move away
-Occurs if the gas/powder is flammable
Oxidation - ANSWER- -Gain of oxygen by an atom, molecule or ion
-Loss of electron from an atom, molecule or ion
What do oxidising agents do - ANSWER- -Give oxygen
-Remove electron
Reduction - ANSWER- -Removal of oxygen in a compound
-Gain of electrons from an atom molecule or ion
What do reducing agents do - ANSWER- -Remove oxygen
, -Donate electrons
Redox reaction - ANSWER- Reaction which involves both oxidation and reduction
-Oil rig happen simultaneously
eg. When a metal oxide is being displaced
-Electrolysis
State the raw materials used in the manufacture of ammonia - ANSWER- nitrogen from air
hydrogen from natural gas
State a use for N₂ - ANSWER- making ammonia
The following reaction is used to manufacture ammonia in the Haber process
N₂ + 3H₂ → 2NH₃ ΔH = -92KJ/mol
The reaction is carried out at 450°C but the reaction would be faster if a higher temperature were
used.
Suggest why a higher temperature is not used in the Haber process - ANSWER- Yield would
decrease and energy costs would increase
State the temperature used for the manufacture of ammonia by the Haber process - ANSWER-
450°C
State the pressure used for the manufacture of ammonia by the Haber process - ANSWER- 200
atm
State the catalyst used for the manufacture of ammonia by the Haber process - ANSWER- Iron
How is ammonia separated from unreacted hydrogen and nitrogen in the Haber process? -
ANSWER- The reaction mixture is cooled until the ammonia condenses into a liquid
