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.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Electricity is conducted in metals due to the presence of a giant structure or lattice arrangement of atoms. In this structure, the atoms are closely packed together, allowing for the movement of positive ions. Crucially, metals have delocalized or free electrons, which means that these electrons are not associated with a specific atom and can move freely throughout the metal. This movement of electrons allows for the conduction of electric current as they can flow through the metal.
Step 2
Describe how the structure of an alloy is different from the structure of a pure metal.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
An alloy, which is a mixture of different metals, has a structure that contains various types and sizes of atoms. Unlike pure metals, where the atoms are uniform, alloys exhibit distorted layers due to the presence of different sized atoms. This structural distortion enables the layers within the alloy to slide past each other less easily, contributing to properties such as increased strength.
Step 3
Why is Nitinol used in dental braces?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Nitinol is used in dental braces because it is a smart alloy, capable of returning to its original shape after being deformed. This property allows for effective orthodontic adjustments.
Step 4
Suggest one reason why coins are not made of pure copper.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
One reason coins are not made of pure copper is that pure copper is too soft, making it unsuitable for enduring wear and tear.
Step 5
Complete the sentence: Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and ...........................................
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and alumina (Al₂O₃).
Step 6
How can the same reaction produce two different products?
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The same reaction can produce two different products due to variations such as different conditions, catalysts, or temperatures during the polymerization process.
Step 7
Give two reasons why instrumental methods of analysis are used to detect impurities in metals.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
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 amounts.
