1403094
Descrição
FlashCards por Melissa Quail, atualizado more than 1 year ago
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Criado por Melissa Quail
aproximadamente 10 anos atrás
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| Questão | Responda |
| What is the ionic equation for what happens to aluminium when it reacts with oxygen? | Al -> Al3+ +3e- |
| What is the ionic equation for what happens to oxygen when it reacts with aluminium? | O + 2e- -> O2- |
| What type of ions to metals form? | Positive |
| What is reduction? | The removal of oxygen from a compound |
| What are unreactive metals found in their natural state called? | Native metals |
| What is an ore? | A rock containing enough metal to make it economic to extract |
| What is a displacement reaction? | A reaction where a more reactive element 'pushes' a less reactive element out of its compound. |
| Give two examples of a reduction reaction. | C +2CuO -> CO₂ + 2Cu and 2Fe₂O₃ + 3C -> 4Fe + 3CO₂ |
| How can copper be extracted from its ore using carbon? | Displacement reaction: Carbon + Copper Oxide -> Carbon Dioxide + Copper |
| List the reactivity series | Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Tin Lead Copper Silver Gold Platinum |
| What metals can be extracted using carbon? | Zinc Iron Tin Lead |
| List some environmental problems caused by mining metal ores | Scars on the landscape Damage of habitats Noise and dust pollution Machinery emits greenhouse gases Areas water becomes acidic Waste rock Sulphur dioxide from smelting which causes acid rain |
| Explain what Phytomining is | Plants are grown on soil that contains too little metal to be used for conventional exploitation but still contains some metal. As the plants grow, they absorb the metal ions in the soil through their roots. The plants are then harvested and burned. The plant ash contains a high concentration of the metal so then the metal can be extracted using electrolysis or a displacement reaction. |
| What are the advantages of phytomining compared to open cast mining? | It doesn't harm the landscape because it doesn't involve digging deep pits and doesn't leave a lot of waste rock. It is also relatively inexpensive and makes use of low grade metal ores. |
| What are the disadvantages of phytomining compared to open cast mining? | It is a long process and carbon dioxide is released when the plants are burned. The metal produced is often less good because some impurities remain. |
| What are the advantages of recycling metals? | Money is saved on extracting metals from their ores Reduced pollution Less used of fossil fuels to supply the electricity used in electrolysis Less pits dug in ground |
| What are the disadvantages of recycling metals? | Recycling metals can produce harmful and toxic chemicals which harm the environment. It can also be time consuming to separate the rubbish in order to recycle them. and this can cause more problems and money than it's worth. |
| What are the advantages of using metals in construction? | Aluminium alloys are corrosion resistant Good electrical conductors - copper is good for wiring Malleable - lead is good for sealing joints on roofs Strong - steel is good for girders |
| What are the disadvantages of using metals in construction? | More expensive than concrete Extraction of metals from their ores causes environmental problems Iron and steel can rust inside reinforced concrete, causing it to collapse |
| How is iron extracted from its ore? | Iron ore (iron oxide) is heated in a blast furnace and a displacement reaction takes place. |
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