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a) Most metals are extracted from rocks found in the Earth’s crust - Edexcel - GCSE Chemistry - Question 4 - 2017 - Paper 1
Question 4
a) Most metals are extracted from rocks found in the Earth’s crust. (i) Iron is extracted from iron oxide. The iron oxide, Fe₂O₃, is heated with carbon. Complete th... show full transcript
Worked Solution & Example Answer:a) Most metals are extracted from rocks found in the Earth’s crust - Edexcel - GCSE Chemistry - Question 4 - 2017 - Paper 1
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Use the information in the table to explain why gold alloys, rather than pure gold, are often used in items of jewellery
Answer
Gold alloys, such as 18-carat gold, are preferred because they combine the desirable properties of gold with added strength. For instance, while 24-carat gold is pure gold, it is less durable and easier to damage. In contrast, 18-carat gold maintains a balance of strength and value, making it more suitable for everyday wear in jewellery.
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Explain why this method has to be used
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Electrolysis is required to extract sodium because it is a highly reactive metal. This method allows for the separation of sodium from its compounds, such as sodium chloride, without the risk of it reacting with carbon or other reductants at high temperatures.
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Explain what is meant by a shape memory alloy
Answer
A shape memory alloy is a unique material that can 'remember' its original shape. When deformed, it can return to its pre-set shape upon heating. This property is particularly useful in medical applications, such as stents, where the alloy can expand and provide support once it reaches body temperature.