C2b - Construction materials Flashcards
What are aluminium, iron, glass and brick manufactured and where are these substances found(4)
aluminium and iron from ores
brick from clay
glass from sand
All are found in the Earth’s crust
Compare the hardness of limestone, marble and granite
granite > marble > limestone
Explain why granite, marble and limestone have different hardness (3)
limestone is a sedimentary rock formed from shells and skeletons of sea creatures; large grains joined weakly
marble is a metamorphic rock made by the action high pressures and temperature on limestone over long time, which changes the crystal structure; smaller grains joined together more strongly than in limestone
granite is an igneous rock; formed when magma cools and solidifies, interlocking crystals are joined together more strongly than the grains in marble, making it very hard
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
CaCO3 → CaO + CO2
What type of reaction is the decomposition of limestone
thermal decomposition reaction
Describe thermal decomposition
a reaction in which, when heated, one substance is chemically changed into at least 2 new substances
How is cement made
when powdered limestone and powdered clay are heated together
Describe how concrete is made(2)
cement, sand, aggregate and water are mixed together
mixture then allowed to set
What type of material is reinforced concrete
composite material
Why is reinforced concrete a better construction material than non-reinforced concrete? (3)
it has useful properties from both the materials it contains:
- concrete is hard and strong in compression
- steel is flexible and strong in tension (high tensile strength)
