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)
- 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)
- 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 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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