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what two raw materials are used to make cement
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what 3 substances is cement mixed with to make concrete
- sand
- water
- aggregate (crushed rock)
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what raw material is mixed with limestone and heated in a kiln to produce cement
clay
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in the kiln the raw materials are heated to about 1500°C . The limestone (calcium carbonate) is broken down at this temperature . Complete the word equation for this reaction
calcium carbonate ==> ------- ---- + carbon dioxide
calcium carbonate ===> calcium oxide + carbon dioxide
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suggest one major cost of this process (making cement by nmixing clay and lim estone and heating them in a kiln) other than the cost of the raw materials
the cost of the fuel needed to power the kiln
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name a naturally occuring form of calcium carbonate
limestone
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what does thermal decomposition mean
the breaking down of a substance using heat
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an old lime kiln made in the ground is shown
suggest and explain the purpose of the coal
the coal will react with the oxygen , and the coal will , burn this will help keep the temperature high
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write a word equation for the thermal decomposition of calcium carbonate
calcium carbonate ==> calcium oxide + carbon dioxide
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when drops of cold water are added tocalcium oxide cracks appear in the white solid , give the chemical name of the white solid formed , give a use of this solid
- name : calcium hydroxide
- use : to neutralise acidic fields , or to make cement or mortar
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limestone has many uses . choose from the list two important materials made from limestone
cement , disel , glass , poly(ethene) , sodium hydrocide , sulphuric acid
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the diagram shows a lime kiln . the limestone is heated by burning coal
suggest why hot air is blown into the lime kiln
to allow the coal to burn
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give two reactions which produce carbon dioxide in the lime kiln
- calcium carbonate ==> calcium oxide + carbon dioxide
- carbon + oxygen ==> carbon dioxide
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calcium oxide can be converted into calium hydroxide by adding water . write a word equation to represent this reaction
calcium oxide + water ==> calcium hydroxide
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why do farmers sometimes add calcium hydroxide to acidic soil
to neutralise the soil
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