Two pieces of metal can be joined by welding them together - Edexcel - GCSE Chemistry - Question 1 - 2013 - Paper 1
Question 1
Two pieces of metal can be joined by welding them together.
(i) Complete the sentence by putting a cross (✗) in the box next to your answer.
The structure of a meta... show full transcript
Worked Solution & Example Answer:Two pieces of metal can be joined by welding them together - Edexcel - GCSE Chemistry - Question 1 - 2013 - Paper 1
Step 1
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The correct answer is C: cations in a sea of electrons. This describes the metallic bonding structure where positive ions are surrounded by a delocalized sea of electrons.
Step 2
State why a high temperature has to be used.
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Answer
Metals have high melting points due to strong metallic bonds that need a lot of energy to break. A high temperature is required to provide this energy to melt the metal.
Step 3
Explain why an atmosphere of argon is used.
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Answer
An atmosphere of argon is used during welding to prevent oxidation of the metal surfaces. Argon is an inert gas that does not react with metals, ensuring a clean weld.
Step 4
Write the balanced equation for this reaction.
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Answer
The balanced equation for the reaction between iron and bromine is:
ightarrow 2FeBr_3$$
Step 5
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The correct answer is B: brown liquid. At room temperature, iodine is typically found as a brown liquid.
Step 6
Use the information in the table to explain the order of reactivity of the three halogens.
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Answer
From the table, chlorine and bromine do not displace iodide ions, indicating that iodine is less reactive than both chlorine and bromine. Therefore, the order of reactivity is chlorine > bromine > iodine.
