This question is about metals and alloys - AQA - GCSE Chemistry - Question 3 - 2015 - Paper 2
Question 3
This question is about metals and alloys.
3 (a) Explain how electricity is conducted in a metal.
To gain full marks you must include a description of the structure... show full transcript
Worked Solution & Example Answer:This question is about metals and alloys - AQA - GCSE Chemistry - Question 3 - 2015 - Paper 2
Step 1
Explain how electricity is conducted in a metal.
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Answer
Electricity is conducted in a metal due to its structure and bonding. Metals have a giant metallic structure where atoms are arranged in layers. In this arrangement, positive ions are surrounded by a sea of delocalized electrons. The delocalized electrons are free to move throughout the metal, which allows them to carry electrical charge and form an electric current. Consequently, the mobility of these electrons is what enables electricity to flow through metallic substances.
Step 2
Describe how the structure of an alloy is different from the structure of a pure metal.
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Answer
An alloy consists of a mixture of different metals or a combination of metals with non-metals. This means that the structure of an alloy contains different types or sizes of atoms, leading to varying atomic arrangements when compared to pure metals. In addition, the layers in an alloy are distorted due to the presence of other atoms, impeding their ability to slide over each other as easily as in pure metals.
Step 3
Why is Nitinol used in dental braces?
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Answer
Nitinol is used in dental braces because it is a shape memory alloy. This means that it can return to its original shape after being deformed, allowing for effective and gentle corrections of dental alignment over time.
Step 4
Suggest one reason why coins are not made of pure copper.
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Answer
One reason why coins are not made of pure copper is that copper is too soft, making it less durable for everyday use.
Step 5
Complete the sentence.
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Answer
Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and aluminium oxide.
Step 6
How can the same reaction produce two different products?
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Answer
The same reaction can produce two different products due to varying conditions such as differences in temperature, catalyst, or pressure during the polymerization process of the same monomer.
Step 7
Give two reasons why instrumental methods of analysis are used to detect impurities in metals.
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Answer
Instrumental methods of analysis are used to detect impurities in metals because they are accurate and sensitive, allowing for the detection of even small sample sizes.
