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| Question | Answer |
| A rock that contains enough metal to make it worth mining is called an ......... Only the most unreactive metals, such as ............ and ..............., occur as .............. in their ores. The rest of the metal s are found as ................, from which the metals have to be ............ . | ore silver gold elements compounds extracted |
| How do you extract potassium from a compound? | electrolysis of the molten chloride or molten oxide |
| How do you extract aluminium from a compound? | electrolysis of the molten chloride or molten oxide |
| How do you extract zinc from a compound? | heat with a reducing agent such a carbon or carbon monoxide |
| Electrolysis is the most ............. method of extraction but it is very ............... since it uses a lot of electricity. | powerful expensive |
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Label this diagram.
Image:
white (image/png)
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A= Positive electrode B= Negative electrode C=Electrolyte D=tapping hole E= insulation |
| When extracting aluminium what is -the positive electrode made of? -the negative electrode made of? -the electrolyte? | -graphite (carbon) -graphite (carbon) -solution of aluminium oxide dissolved in molten cryolite |
| -What is the main ore of aluminium? -This is first purified to produce? -Why is aluminium oxide dissolved in molten cryolite to make the electrolyte? | -Bauxite -Aluminium oxide -Aluminium oxide has a very high melting point and when dissolved in molten cryolite it has a much lower melting point and is also a better conductor of electricity. |
| When extracting aluminium what the reaction at the negative electrode? What happens after this? | Al 3+ + 3e- ---> Al The aluminium melts and collects at the bottom of the cell. It is then tapped off. |
| When extracting aluminium what is the reaction at the positive electrode? What happens with this product? | Some of the oxygen produced reacts with the graphite (carbon) to produce carbon dioxide gas, meaning the positive electrode gradually burns away and needs to be replaced. |
| State the steps of how to extract aluminium. | 1. Purify the ore, bauxite, to produce aluminium oxide. 2. Dissolve in molten cryolite. 3. At the negative electrode aluminium melts and collects at the bottom of the cell. 4. Aluminium is tapped off. 5. Oxygen produced at positive electrode 6. reacts with the graphite -produce CO2. 7. replace the positive electrodes regularly |
| Draw a diagram of the extraction of iron. |
Image:
iron (image/jpg)
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| The raw material used in iron extraction are... | Iron ore (haematite) Coke (carbon) Limestone (calcium carbonate) air |
| In iron extraction oxygen (in the .......) reacts with the coke to form .............. .............. . Equation | air carbon dioxide C (s) + O2 (g) ---> CO2 (g) |
| In Iron extraction carbon dioxide reacts with coke to form ........... ............... . Equation | carbon monoxide CO2 (g) + C (s) ---> 2CO (g) |
| .......... ............... reduces the iron (III) oxide in the iron ore Equation Then what happens? | carbon monoxide Fe2O3 (s) + 3CO(g) ---> 2 Fe (l) + 3CO2 (g) The iron melts and collects at the bottom of the furnace, where it is tapped off. |
| What is the limestone in iron extraction used for? | Calcium carbonate in limestone decomposes to form calcium oxide. CaCO3 (s) --> Cao (s) + CO2 (g) The calcium oxide reacts with silicon dioxide which is an impurity in the iron ore, to form calcium silicate. CaO(s) + Sio2 (s) --> CaSio3 (l) Calcium silicate melts and collects as molten slag on top of the iron which is tapped off separately. |
| Name 5 uses of aluminium and the most important properties needed. | Aeroplane bodies- high strength to weight ratio Overhead power cables- Good conductor of electricity Saucepans- Good conductor of heat Food cans - Non-toxic Window frames- resists corrosion |
| Name 3 uses and the most important properties for these. | Car bodies- strong (withstand collisions) Iron nails - Strong Ships, Girders, Bridges - Strong |
| What is crude oil? | A naturally occurring mixture of hydrocarbons |
| Cruse oil has no direct use. It has to be .............. before it is of any use. The first step in refining of crude oil is .............. ............ . This is carried out in a ............... ...................., which is ...... at the bottom and .............. towards the top. | refined fractional distillation fractioning column hot cooler |
| When refining crude oil it is split into .........., a ................... of hydrocarbons with similar .................. ..................... . | fractions mixture boiling points |
| How does refining crude oil work? | -Crude oil heated to convert it to vapour. -Vapour fed into the bottom of the fractioning column -Hydrocarbons with high boiling points immediately turn into liquids and are tapped off at the bottom of the column. -The hydrocarbons that have boiling points lower than 400 remain as gases and rise up the column. As they rise they cool down. -Different fractions will condense at different points and then tapped off. |
| Name the order of the different fractions from the lowest temperature (the top of the column) to the highest temperature (the bottom of the fractioning column). | Refinery gases (out of the top) gasoline (petrol) Kerosene Diesel gas (gas oil) [crude oil come in] fuel oil bitumen (out of bottom) |
| List a major use for each of the fraction once refined from crude oil. | Refinery gases- bottled gas for camping Gasoline- petrol for cars Kerosene- Fuel for aeroplanes, 'oil' for central heating boilers in the home, 'paraffin' for small heaters and lamps Diesel oil- Fuel for buses, lorries and cars Fuel oil- fuel for ships and industrial heating Bitumen- Road surfaces and covering flat roofs of buildings |
| Why did chemists invent cracking? | The amount of higher boiling point fractions in crude oil is far greater than is needed. The smaller hydrocarbons are in far greater demand. |
| What is cracking? | A method of converting the long-chain hydrocarbons in the high boiling point fractions into shorter hydrocarbons. |
| How does cracking work? | Long-chain hydrocarbon (alkane) molecules are passed over a catalyst (either silica or aluminium oxide) and heated to about 600-700 degrees. They break down into short chain alkane molecules and at least one alkene molecule. |
| Why are cars now fitted with catalytic converters? | Because incomplete combustion of petrol or diesel produces carbon monoxide- poisonous. Also nitrogen and oxygen react together and form nitrogen oxide which when dissolved in water form acid rain. Catalytic converters try to convert as much carbon monoxide into carbon dioxide as possible and reconvert the oxides of nitrogen into nitrogen and oxygen. |
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