GCSE Chemistry
Q&A
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
What happens to the unreacted hydrogen and nitrogen in the Haber process? - answer-
Recycled
State the uses of ammonia - answer-manufacture of nitric acid and fertilisers
Suggest the names of two elements, other than nitrogen, that are likely to be present in NPK
fertiliser - answer-potassium and phosphorous
Write a chemical equation for the reaction between ammonia and nitric acid -
answer-NH₃ + HNO₃ → NH₄NO₃
,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
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 the electrode 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⁻
,State the uses of sodium hydroxide. (Triple science only!) - answer-manufacture of bleach,
paper and soap
State the uses of chlorine. (Triple science only!) - answer-sterilising water supplies and the
manufacture of bleach and hydrochloric acid
Explain what is an addition polymer - answer-An addition polymer is large molecule made by
adding many small molecules (each containing a double bond) to form one much larger
molecule
Explain what is a monomer - answer-Monomers are the many small molecules (such as ethene)
which add together to make a polymer
Describe, in terms of structure and bonding, what happens when ethene molecules are
converted into poly(ethene) - answer-One bond in the double bond breaks. Monomers join
together to form a long chain. Polymer contains only single bonds
Draw the equation to show the formation of poly(ethene) - answer-
Draw the equation to show the formation of poly(propene) - answer-
Draw the displayed formula for the repeat unit of poly(ethene) - answer-
Draw the displayed formula for the repeat unit of poly(propene) - answer-
Draw the displayed formula for the repeat unit of poly(chloroethene). (Triple science only!) -
answer-
State the uses of poly(ethene) - answer-Plastic bags and bottles
State the uses of poly(propene) - answer-Plastic crates and ropes
State uses for poly(chloroethene). (Triple science only!) - answer-Plastic piping and cable
insulation
, What is meant by the term biodegradable? - answer-The break down of a substance by
microorganisms
Explain why additional polymers are hard to dispose of - answer-They are inert as they have
strong C-C bonds.
This makes them non-biodegradeable.
What type of reaction is used to form nylon? (Triple science only!) - answer-Condensation
polymerisation
During condensation polymerisation, what else forms other than the polymer? (Triple science
only!) - answer-A small molecule such as H₂0 or HCl
What is crude oil? - answer-A mixture of hydrocarbons
Explain how crude oil is separated into fractions - answer-Crude oil is separated by fractional
distillation.
Crude oil is heated and the oil evaporates.
It then goes into the tower.
As the vapours rise up the tower the temperature falls.
Different sized fractions condense at different heights because they have different boiling points.
Smaller molecules condense high up the tower.
Larger molecules condense low down in the tower.
Then the fractions are collected.
Recall the names of the main fractions obtained from crude oil - answer-refinery gases
gasoline
kerosene
diesel
fuel oil
bitumen
Q&A
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
What happens to the unreacted hydrogen and nitrogen in the Haber process? - answer-
Recycled
State the uses of ammonia - answer-manufacture of nitric acid and fertilisers
Suggest the names of two elements, other than nitrogen, that are likely to be present in NPK
fertiliser - answer-potassium and phosphorous
Write a chemical equation for the reaction between ammonia and nitric acid -
answer-NH₃ + HNO₃ → NH₄NO₃
,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
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 the electrode 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⁻
,State the uses of sodium hydroxide. (Triple science only!) - answer-manufacture of bleach,
paper and soap
State the uses of chlorine. (Triple science only!) - answer-sterilising water supplies and the
manufacture of bleach and hydrochloric acid
Explain what is an addition polymer - answer-An addition polymer is large molecule made by
adding many small molecules (each containing a double bond) to form one much larger
molecule
Explain what is a monomer - answer-Monomers are the many small molecules (such as ethene)
which add together to make a polymer
Describe, in terms of structure and bonding, what happens when ethene molecules are
converted into poly(ethene) - answer-One bond in the double bond breaks. Monomers join
together to form a long chain. Polymer contains only single bonds
Draw the equation to show the formation of poly(ethene) - answer-
Draw the equation to show the formation of poly(propene) - answer-
Draw the displayed formula for the repeat unit of poly(ethene) - answer-
Draw the displayed formula for the repeat unit of poly(propene) - answer-
Draw the displayed formula for the repeat unit of poly(chloroethene). (Triple science only!) -
answer-
State the uses of poly(ethene) - answer-Plastic bags and bottles
State the uses of poly(propene) - answer-Plastic crates and ropes
State uses for poly(chloroethene). (Triple science only!) - answer-Plastic piping and cable
insulation
, What is meant by the term biodegradable? - answer-The break down of a substance by
microorganisms
Explain why additional polymers are hard to dispose of - answer-They are inert as they have
strong C-C bonds.
This makes them non-biodegradeable.
What type of reaction is used to form nylon? (Triple science only!) - answer-Condensation
polymerisation
During condensation polymerisation, what else forms other than the polymer? (Triple science
only!) - answer-A small molecule such as H₂0 or HCl
What is crude oil? - answer-A mixture of hydrocarbons
Explain how crude oil is separated into fractions - answer-Crude oil is separated by fractional
distillation.
Crude oil is heated and the oil evaporates.
It then goes into the tower.
As the vapours rise up the tower the temperature falls.
Different sized fractions condense at different heights because they have different boiling points.
Smaller molecules condense high up the tower.
Larger molecules condense low down in the tower.
Then the fractions are collected.
Recall the names of the main fractions obtained from crude oil - answer-refinery gases
gasoline
kerosene
diesel
fuel oil
bitumen
