Chemistry (C1A)

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Rocks And Buildings

Limestone And Its Uses

  • Chemical equation for limestone = Calcium Carbonate (CaCO3)
  • Powdered limestone + sand + heat = glass
  • Powedered limestone + powdered clay +heat = cement
  • Cement powder + water + sand + crushed rocks = concrete
  • When limestone is strongly heated in a kiln (this is called thermal decomposition) this leaves Quicklime (Calcium Oxide) and Carbon Dioxide (see below for the chemical formula)
  • CaCo3 + heat > CaO + CO2 (Limestone + Heat > Calcium Oxide + Carbon Dioxide)
  • When water is added to quicklime, it produces slaked lime (or calcium hydroxide) See chemical formula below.
  • CaO + H2O > Ca(OH)2 (Calcium Oxide + Water > Calcium Hydroxide)
  • When Carbon Dioxide is added to calcium hydroxide, calcium carbonate is left along with water (CaCO3 is insoluble in water). This can be used as lime mortar, a material used to construct buildings.
  • Ca(OH)2 + CO2 > CaCO3 + H2O (Calcium Hydroxide + Carbon Dioxide > Limestone + Water)
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Rocks And Metals (part 1)

Extracting metals

  • Metals found in the earth's crust
  • A metal ore is when there is enough of a metal or metal compound in the rock to make it worth extracting.
  • Some metals (like gold) can be found in their native state (as the metals themselves).
  • Reactivity series: Potassium, Sodium, Calcium, Magnesium, Aluminium,Carbon, Zinc, Iron, Tin, Lead, Copper, Silver, Gold, Platinum (Please Sir Lancelot, Can My Alligator Zoom In To Learn Computer Science + Geography Please?)
  • The reactivity series is useful to decide the best way of extracting each metal from its ore.
  • Metals more reactive than Carbon can't be extracted from their ores using Carbon.
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Rocks And Metals (part 2)

Extracting Iron

  • We extract iron from its iron ore by reducing it with carbon in a blast furnace.
  • The materials needed to make iron are iron ore (haematite), coke and limestone.
  • Hot air is blown into the blast furnace. This makes the coke burn, which heats the furnace and forms carbon dioxide.
  • As the temperature gets higher, the carbon dioxide and the coke react again to form carbon monoxide gas.
  • The carbon monoxide reacts with the iron oxide, removing its oxygen and reducing it to molten iron.
  • Molten iron is taken from the bottom of the blast furnace.
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Rocks And Metals (part 3)

Alloys In Everyday Use

  • Copper, gold and aluminium are all alloyed with other metals to make them more useful.
  • By adding different amounts of elements, we can control the alloy's properties.
  • When Shape Memory Alloys (or SMAs) are heated, they return to their original shape. They can be used in medicine and dentistry.

Aluminium and titanium

  • Aluminium and titanium are useful because they can resist corrosion.
  • It's expensive to extract them because it requires a lot of energy.
  • Recycling aluminium is important as it saves energy.
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Crude Oil

Crude Oil

  • Crude Oil is a mix of different compounds. A lot of these are Hydrocarbons (containing only carbon and hydrogen).
  • Alkanes are saturated hydrocarbons (they contain as much hydrogen as possible)
  • We separate crude oil using fractional distillation.
  • The higher the boiling point, the longer the chain.
  • The higher the volatility, the shorter the chain
  • The higher the viscosity, the longer the chain.
  • The higher the flammability, the smaller the chain.
  • Fractional column (from bottom): Residue, Diesel, Kerosene, Gasoline, Petroleum. The smallest are at the top.
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Comments

nush

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Really Helpful, thanks :)

Ben Sharpe

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Very helpful and precise, thanks.

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