AQA GCSE Science CHEMISTRY Unit C1.2 Limestone and building materials

• Know that rocks provide essential building materials.

• Know that limestone is a naturally occurring resource that provides a starting point for the manufacture of cement and concrete.

• Using your skills, knowledge and understanding you are expected to be able to:

  • consider and evaluate the environmental, social and economic effects of exploiting limestone and producing building materials from it,

  • evaluate the developments in using limestone, cement and concrete as building materials, and their advantages and disadvantages over other materials.

• You should know that limestone is needed for buildings and that the positive benefits of using this material should be considered against the negative aspects of quarrying.

• Your expected knowledge of building materials is limited to limestone, cement and concrete.

• You are not expected to have knowledge of particular developments, but, information may be supplied in examination questions for you to evaluate.

• Knowledge of the properties of other building materials is not required, but you may be provided with information about materials such as timber, stone, glass and steels in the examination so that you can make comparisons about their uses.

AQA GCSE Science CHEMISTRY Unit C1.2.1 Calcium carbonate

• a) You should know that limestone is mainly composed of the compound calcium carbonate (CaCO₃), is quarried and can be used as a building material.

• b) Know that calcium carbonate can be decomposed by heating to make calcium oxide and carbon dioxide.

  • You should know this is an example of thermal decomposition, meaning 'breaking down with heat'.

• c) Know that the carbonates of magnesium, copper, zinc, calcium and sodium decompose on heating in a similar way.

  • Your knowledge and understanding of metal carbonates is limited to metal carbonates decomposing on heating to give carbon dioxide and the metal oxide.

  • You should know that not all carbonates of metals in Group 1 of the periodic table decompose at the temperatures reached by a Bunsen burner flame.

• d) Calcium oxide reacts with water to produce calcium hydroxide, which is an alkali that can be used in the neutralisation of acids.

  • You do not need to know the common names quicklime and slaked lime for calcium oxide and calcium hydroxide respectively.

• e) Know that a solution of calcium hydroxide in water (limewater) reacts with carbon dioxide to produce calcium carbonate.

  • Know that limewater is used as a test for carbon dioxide and carbon dioxide turns limewater cloudy (formation of a white precipitate).

    • You should be familiar with using limewater to test for carbon dioxide gas.

• f) Know that carbonates react with acids to produce carbon dioxide, a salt and water.

  • Know that limestone is damaged by acid rain which reacts with it.

  • Your knowledge of the reaction of carbonates with acids is limited to the reactions of magnesium, copper, zinc, calcium and sodium eg observations, products and equations.

• g) Know that limestone is heated with clay to make cement.

  • Know that cement is mixed with sand to make mortar and with sand and aggregate to make concrete.

• Hopefully your practical work to develop skills and understanding has included the following (which should also be revised, helps in understanding 'how science works' and context examination questions):

  • investigating the limestone cycle:

    • decomposition of CaCO₃ to give CaO,

    • reaction with water to give Ca(OH)₂,

    • addition of more water and filtering to give limewater and use of limewater to test for CO₂,

  • thermal decomposition of CaCO₃ to show limelight - glowing white hot 'lime'

  • honeycomb demonstration: heat sugar syrup mixture to 150 °C and add sodium bicarbonate

  • making concrete blocks in moulds, investigation of variation of content and carrying out strength tests

  • designing and carrying out an investigation of trends in the thermal decomposition of metal carbonates

  • investigation of the reaction of carbonates with acids.

• Revision notes and quizzes

  • Notes on limestone, lime, uses, decomposition of carbonates and reactions with acids

  • Chemical economics of industrial processes and sociological & environmental issues

  • Economic & environmental issues on mineral extraction

  • Easy GCSE Multiple Choice Quiz on limestone chemistry

  • Harder GCSE Multiple Choice Quiz on limestone chemistry

  • AQA Word-fill on Limestone - its chemistry and uses (gap-fill via drop-down menu)

  • AQA Word-fill more questions on carbonates

  • General GCSE word-fill exercise on limestone chemistry and uses

  • How to write word & symbol equations