C2: Chemical resources Revision List

GCSE Chemistry C2 (OCR B712): Chemical Resources

Combined and triple award Science revision list for AQA GCSE Chemistry C2 Core Science 9-1 Specification. The revision list is also relevant to OCR GCSE Chemistry.

C2: Chemical resources Revision List

October 22, 2017 admin

FUNDAMENTAL CHEMICAL CONCEPTS

  • Understand that in a chemical reaction reactants are changed into products.
  • Recognise the reactants and products in a word equation.
  • Construct word equations given the reactants and products.
  • Recognise the reactants and the products in a symbol equation.

 

  • Work out the number of elements in a compound given its formula.
  • Work out the number of atoms in a formula with no brackets.
  • Work out the number of each different type of atom in a formula with no brackets.

 

  • Recognise whether a substance is an element or a compound from its formula.
  • Work out the names of the different elements in a compound given its formula.
  • Recognise whether a particle is an atom, molecule or ion given its formula.
  • Understand that atoms contain smaller particles one of which is a negative electron.

 

  • Recall that two types of chemical bond holding atoms together are:
    • ionic bonds
    • covalent bonds

 

  • Understand that a molecule is made up of more than one atom joined together.
  • Understand that a molecular formula shows the numbers and types of atom in a molecule.
  • Work out the number of atoms in a displayed formula.
  • Work out the names of the different elements in a compound given its displayed formula.
  • Work out the number of each different type of atom in a displayed formula.

 

  • Construct word equations (not all reactants and products given)
  • Construct balanced symbol equations given the formulae (no brackets) of the reactants and products.
  • Explain why a symbol equation is balanced.

 

  • Construct balanced symbol equations given the formulae (some or all with brackets) of the reactants and products.(HL)
  • Construct balanced symbol equations given the names of the reactants and products.(HL)
  • Work out the number of atoms in a formula with brackets.
  • Work out the number of each type of different atom in a formula with brackets.

 

  • Recall the formula of the following substances:
    • calcium carbonate and calcium oxide
    • carbon dioxide, hydrogen and water
    • sodium chloride and potassium chloride
    • ammonia and nitrogen
    • hydrochloric acid.

 

  • Recall the formula of the following substances:(HL)
    • nitric acid and sulfuric acid
    • copper oxide, sodium hydroxide, potassium hydroxide and sodium carbonate
    • potassium sulfate, sodium sulfate and ammonium sulfate
    • calcium chloride, magnesium chloride
    • magnesium sulfate and copper(II) sulfate.

 

  • Understand that a displayed formula shows both the atoms and the bonds in a molecule.
  • Write the molecular formula of a compound given its displayed formula.
  • Construct balanced equations using displayed formulae.(HL)
  • Understand that positive ions are formed when electrons are lost from atoms.
  • Understand that negative ions are formed when electrons are gained by atoms.
  • Understand that an ionic bond is the attraction between a positive ion and a negative ion.
  • Understand that a covalent bond is a shared pair of electrons.
  • Explain how an ionic bond is formed.(HL)
  • Explain how a covalent bond is formed.(HL)

C2a The structure of the Earth

  • Describe the structure of the Earth as a sphere with a thin rocky crust, a mantle and an iron core.
  • Understand how the movement of tectonic plates results in volcanic activity and earthquakes.
  • Recall that the movement of tectonic plates is very slow (about 2.5cm per year).
  • Understand the timescales involved in the movement of continents.

 

  • Recognise that:
    • many theories have been put forward to explain the nature of the Earth’s surface
    • Earth scientists accept the theory of plate tectonics.

 

  • Explain how the size of crystals in an igneous rock is related to the rate of cooling of molten rock
  • Describe magma as molten rock beneath the surface of the Earth and lava as molten rock at the Earth’s surface.
  • Recall that some volcanoes erupt runny lava, while some erupt thick lava violently and catastrophically.
  • Research examples of people who live near volcanoes and the reasons why.
  • Explain why some people choose to live near volcanoes.

 

  • Describe the lithosphere as the (relatively) cold rigid outer part of the Earth that includes the crust and part of the mantle.
  • Describe the lithosphere as made of tectonic plates that are less dense than the mantle below.

 

  • Explain the problems associated with studying the structure of the Earth:
    • crust is too thick to drill through
    • the need to use seismic waves produced by earthquakes or man-made explosions.

 

  • Explain why the theory of plate tectonics is now widely accepted:
    • it explains a wide range of evidence
    • it has been discussed and tested by a wide range of scientists.

 

  • Describe the mantle as the zone between the crust and the core which is(HL):
    • cold and rigid just below the crust
    • hot and non-rigid at greater depths and therefore able to move

 

  • Describe the theory of plate tectonics(HL):
    • energy transfer involving convection currents in the semi-rigid mantle causing the plates to move slowly
    • oceanic crust more dense than continental crust
    • collision between oceanic plate and continental plate leads to subduction and partial melting
    • plates cooler at ocean margins so sink and pull plates down

 

  • Describe in simple terms the development of the theory of plate tectonics(HL):
    • Wegener’s continental drift theory (1914)
    • continental drift theory not accepted by scientists at the time
    • new evidence in 1960s – sea floor spreading
    • theory of plate tectonics slowly accepted by the scientific community as subsequent research has supported the theory.

 

  • Understand that the type of volcanic eruption depends on the composition of the magma.
  • Describe different types of igneous rocks that are formed from lava(HL):
    • iron-rich basalt is formed from runny lava from a fairly safe volcanic eruption
    • silica-rich rhyolite is formed from thick lava from an explosive eruption

 

  • Explain why geologists study volcanoes:
    • to be able to forecast future eruptions
    • to reveal information about the structure of the Earth

 

  • Explain why geologists are now able to better forecast volcanic eruptions but not with 100% certainty.(HL)

C2b Construction materials

  • Recall that some rocks are used in construction of buildings and roads:
    • granite, limestone, marble and aggregates.

 

  • Explain why there are environmental problems when rocks are quarried or mined from the ground:
    • landscape destroyed and has to be reconstructed when the mining or quarrying has finished
    • increased noise, traffic and dust

 

  • Recall that limestone thermally decomposes to make calcium oxide and carbon dioxide.
  • Recall that limestone and marble are both forms of calcium carbonate.
  • Describe how concrete is made:
    • cement, sand, aggregate and water are mixed together
    • mixture then allowed to set.

 

  • Describe how concrete can be reinforced using a steel support.
  • Relate some construction materials to the substances found in the Earth’s crust from which they are manufactured:
    • aluminium and iron from ores
    • brick from clay
    • glass from sand.

 

  • Compare the hardness of limestone, marble and granite.
  • Explain why granite, marble and limestone have different hardness(HL):
    • limestone is a sedimentary rock
    • marble is a metamorphic rock made by the action of high pressures and temperatures on limestone
    • granite is an igneous rock

 

  • Construct the word equation for the decomposition of limestone calcium carbonate -> calcium oxide + carbon dioxide
  • Construct the balanced symbol equation for the decomposition of limestone (given some formulae): CaCO3 → CaO + CO2
  • Describe thermal decomposition as a reaction in which, when heated, one substance is chemically changed into at least two new substances.
  • Construct the balanced symbol equation for the decomposition of limestone (formulae not given)(HL): CaCO3 → CaO + CO2
  • Recall that cement is made when limestone and clay are heated together.
  • Recall that reinforced concrete is a composite material.

 

  • Explain why reinforced concrete is a better construction material than non-reinforced concrete in terms of (HL):
    • hardness of the concrete
    • flexibility and strength of the steel

 

C2c Metals and alloys

  • Recall that copper can be purified by electrolysis.
  • Describe reduction as the removal of oxygen from a substance.
  • Understand how copper can be extracted by heating its ore with carbon.
  • Explain why recycling copper is cheaper than extracting copper from its ore:
    • saves resources
    • uses less energy

 

  • Recognise that brass, bronze, solder, steel, and amalgam are alloys.
  • Recall that alloys are mixtures containing one or more metal elements.
  • Recall one important large scale use for each of the following alloys:
    • amalgam used in tooth fillings
    • brass used in musical instruments, coins and door decorations eg door knockers
    • solder used to join electrical wires.

 

  • Recognise that the properties of an alloy are different from the properties of the metals from which it is made.
  • Interpret data about the properties of metals,including alloys eg hardness, density, boiling point and strength.
  • Suggest properties needed by a metal or alloy for a particular given use.
  • Label the apparatus needed to purify copper by electrolysis.
  • Explain some of the advantages and disadvantages of recycling copper.
  • Describe the use of electrolysis in the purification of copper (HL):
    • impure copper as anode
    • pure copper as cathode
    • copper(II) sulfate solution as electrolyte
    • cathode gains mass because copper is deposited
    • anode loses mass as copper dissolves

 

  • Explain why the electrolytic purification of copper involves both oxidation and reduction (HL):
    • Cu2+ + 2e → Cu as an example of reduction because electrons are gained
    • Cu – 2e → Cu2+ as an example of oxidation because electrons are lost.

 

  • Recall the main metals in each of the following alloys:
    • amalgam – mercury
    • brass – copper and zinc
    • solder – lead and tin.

 

  • Explain why metals, including alloys are suited to a given use given appropriate data (no recall expected).
  • Evaluate the suitability of metals for a given use given appropriate data(HL).
  • Explain how the use of ‘smart alloys’ such as those with a shape memory property have increased the number of applications of alloys (HL):
    • nitinol (nickel and titanium) used to make spectacle frames as the frames will return to their original shape after bending.

C2d MAKING CARS

  • Recall that rusting needs iron, water and oxygen.
  • Recall that aluminium does not corrode in moist conditions.
  • Describe oxidation as the addition of oxygen or the reaction of a substance with oxygen.
  • Interpret simple data about the rate of corrosion of different metals in different conditions (no recall is expected).
  • Compare the properties of iron and aluminium:
    • iron is more dense than aluminium
    • iron is magnetic and aluminium is not
    • iron corrodes (rusts) easily and aluminium does not
    • iron and aluminium are both malleable
    • iron and aluminium are both good electrical conductors

 

  • Recall the major materials needed to build a car:
    • steel, copper and aluminium
    • glass, plastics and fibres

 

  • Describe the advantages of recycling materials:
    • saves natural resources
    • reduces disposal problems.

 

  • Understand that rusting is an oxidation reaction (iron reacts with oxygen forming an oxide).
  • Understand how salt water and acid rain affect rusting.
  • Construct the word equation for rusting:
    • iron + oxygen + water → hydrated iron(III) oxide.

 

  • Explain why aluminium does not corrode in moist conditions.
  • Interpret data about the rate of corrosion of different metals in different conditions (no recall is expected).
  • Understand that alloys often have properties that are different from the metals they are made from and that these properties may make the alloy more useful than the pure metal
    • steel is harder and stronger than iron
    • steel is less likely to corrode than iron.

 

  • Describe advantages and disadvantages of building car bodies from aluminium or from steel:
    • car body of the same car will be lighter with aluminium
    • car body with aluminium will corrode less
    • car body of the same car will be more expensive made from aluminium.

 

  • Explain advantages and disadvantages of building car bodies from aluminium or from steel:(HL)
    • get better fuel economy because the car body of the same car will be lighter with aluminium
    • longer lifetime because the car body with aluminium will corrode less.

 

  • Suggest properties needed by a material for a particular use in a car.
  • Explain why a material used in a car is suited to a particular use given appropriate data (no recall expected)

 

  • Explain the advantages and disadvantages of recycling the materials used to make cars.
  • Explain why new laws specify that a minimum percentage of all materials used to manufacture cars must be recyclable.

 

  • Evaluate information on materials used to manufacture cars (no recall expected)(HL).

C2e Chemical Economics

  • Recall that in the Haber process ammonia is made from nitrogen from the air and hydrogen that comes from the cracking of oil fractions or from natural gas.
  • Describe that the cost of making a new substance depends on:
      • price of energy (gas and electricity)
      • cost of starting materials
      • wages (labour costs)
      • equipment (plant)
      • how quickly the new substance can be made (cost of catalyst).

 

  • Understand that a reversible reaction proceeds in both directions.
  • Recognise that is used to represent a reversible reaction.
  • Recall some of the uses of ammonia:
    • manufacture of fertilisers
    • manufacture of nitric acid.

 

  • Describe how ammonia is made in the Haber process:
    • nitrogen + hydrogen ammonia
    • iron catalyst
    • high pressure
    • temperature in the region of 450°C

 

  • Construct the balanced symbol equation for the manufacture of ammonia in the Haber process (given some or all of the formulae):
    • N2 + 3H2 ⇋ 2NH3

 

  • Explain the conditions used in the Haber process (HL):
    • high pressure increases the percentage yield of ammonia
    • high temperature decreases the percentage yield of ammonia
    • high temperature gives a high rate of reaction
    • 450 °C is an optimum temperature to give a fast reaction with a sufficiently high percentage yield
    • catalyst increases the rate of reaction but does not change the percentage yield.

 

  • Construct the balanced symbol equation for the manufacture of ammonia in the Haber process (formulae not given) (HL):
    • N2 + 3H2 ⇋ 2NH3

 

  • Describe how different factors affect the cost of making a new substance:
    • the higher the pressure the higher the plant cost
    • the higher the temperature the higher the energy cost
    • catalysts reduce costs by increasing the rate of reaction
    • when unreacted starting materials are recycled costs are reduced
    • automation reduces the wages bill

 

  • Explain how economic considerations determine the conditions used in the manufacture of chemicals (HL):
    • rate must be high enough to give a sufficient daily yield of product
    • percentage yield must be high enough to give a sufficient daily yield of product
    • a low percentage yield can be accepted if the reaction can be repeated many times with recycled starting materials
    • optimum conditions used that give the lowest cost rather than the fastest reaction or highest percentage yield.

 

  • Interpret data in tabular and graphical form relating to percentage yield in reversible reactions and changes in conditions (no recall required)(HL).
  • Interpret data about rate, percentage yield and costs for alternative industrial processes (no recall required).
  • Recognise the importance of ammonia in relation to world food production.

C2f Acids and Bases

  • Describe how universal indicator can be used to estimate the pH of a solution.
  • Recall the colour changes with litmus.
  • Recall that an alkali is a soluble base.
  • Understand that an acid can be neutralised by a base or alkali, or vice versa.

 

  • Understand that indicators use colour change to show changes in pH, including:
    • sudden or gradual changes
    • colour changes over different pH ranges.

 

  • Recall that in neutralisation:
    • acid + base → salt + water.
    • Recall that in solution all acids contain H+ ions.

 

  • Understand that the pH of an acid is determined by the concentration of H+ ions.
  • Explain why an acid is neutralised by an alkali in terms of the ions present (HL):
    • acids contain H+
    • alkalis contain OH
    • neutralisation involves the reaction H+ + OH ⇋ H2O

 

  • Construct word equations to show the neutralisation of acids by bases and carbonates (names of the products not given).
  • Recall that carbonates neutralise acids to give water, a salt and carbon dioxide.
  • Explain why metal oxides and metal hydroxides neutralise acids.
  • Predict the name of the salt produced when a named base or carbonate is neutralised by a laboratory acid:
    • sulfuric acid
    • nitric acid
    • hydrochloric acid
    • phosphoric acid

 

  • Construct balanced symbol equations for the neutralisation of acids by bases and carbonates for (HL):
    • sulfuric acid, nitric acid and hydrochloric acid
    • ammonia, potassium hydroxide, sodium hydroxide and copper oxide
    • sodium carbonate and calcium carbonate

 

C2g Fertilisers and crop yields

  • Recall that fertilisers increase crop yield.
  • Recall that plants absorb minerals through their roots.
  • Describe fertilisers as chemicals that provide plants with essential chemical elements.
  • Recall that nitrogen, phosphorus and potassium are three essential elements needed for plant growth.
  • Recognise the essential elements given the formula of a fertiliser.
  • Understand that the use of fertilisers can be beneficial (increasing food supply) and also cause problems eg death of aquatic organisms (eutrophication).

 

  • Identify the apparatus needed to prepare a fertiliser by the neutralisation of an acid with an alkali:
    • burette and measuring cylinder
    • filter funnel.

 

  • Recall the names of two nitrogenous fertilisers manufactured from ammonia eg:
      1. ammonium nitrate
      2. ammonium phosphate
      3. ammonium sulfate
      4. urea
  • Explain why fertilisers must be dissolved in water before they can be absorbed by plants.
  • Identify arguments for and against the use of fertilisers:
    • world population is rising so need to produce more food
    • eutrophication and pollution of water supplies can result from excessive use of fertilisers.

 

  • Explain how the use of fertilisers increases crop yield (HL):
    • replaces essential elements used by a previous crop or provides extra essential elements
    • more nitrogen gets incorporated into plant protein so increased growth.

 

  • Explain the process of eutrophication:
    • run-off of fertiliser
    • increase of nitrate or phosphate in river water
    • algal bloom
    • blocks off sunlight to other plants which die
    • aerobic bacteria use up oxygen
    • most living organisms die

 

  • Predict the name of the acid and the alkali needed to make a named fertiliser, for example:
    • ammonium nitrate.

 

  • Describe the preparation of a named synthetic fertiliser by the reaction of an acid and an alkali (HL):
    • names of reactants
    • experimental method
    • how a neutral solution is obtained
    • how solid fertiliser is obtained

 

C2h Chemicals from the sea: the chemistry of sodium chloride

  • Recall that sodium chloride (salt) can be obtained from the sea or from salt deposits.
  • Recall that the electrolysis of concentrated sodium chloride gives chlorine and hydrogen.
  • Recall that the chemical test for chlorine is that it bleaches moist litmus paper.
  • Recall that sodium chloride is used:
    • as a preservative
    • as a flavouring.

 

  • Understand that sodium chloride is an important raw material in the chemical industry, including use as a source of chlorine and sodium hydroxide.
  • Recall that household bleach, pvc and solvents are made from substances derived from salt.
  • Recall that chlorine is used to sterilise water and to make solvents, household bleach and plastics.
  • Recall that hydrogen is used in the manufacture of margarine.
  • Recall that sodium hydroxide is used to make soap.

 

  • Describe how salt can also be mined as rock salt and by solution mining in Cheshire.
  • Explain how mining for salt can lead to subsidence.
  • Recall the products of the electrolysis of concentrated sodium chloride solution (brine):
    • hydrogen made at the cathode
    • chlorine made at the anode
    • sodium hydroxide is also made

 

  • Explain why it is important to use inert electrodes in the electrolysis of sodium chloride solution.
  1. Explain how the electrolysis of sodium chloride solutio-, H+
  2. cathode 2H+ + 2e → H2
  3. anode 2Cl – 2e → Cl2
  4. ions not discharged make sodium hydroxide.
  • Explain why the electrolysis of sodium chloride involves both reduction and oxidation (HL).
  • Describe how sodium hydroxide and chlorine are used to make household bleach.
  • Explain the economic importance of the chlor-alkali industry (HL).
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