This question is about chemical analysis - AQA - GCSE Chemistry - Question 1 - 2020 - Paper 2
Question 1
This question is about chemical analysis.
A student tested copper sulfate solution and calcium iodide solution using flame tests.
This is the method used.
1. Dip ... show full transcript
Worked Solution & Example Answer:This question is about chemical analysis - AQA - GCSE Chemistry - Question 1 - 2020 - Paper 2
Step 1
What flame colour is produced by copper sulfate solution?
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Answer
The flame colour produced by copper sulfate solution is green, often described as blue-green.
Step 2
Explain why.
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Answer
The student did not clean the metal wire between tests, or the copper sulfate solution was still present. This could lead to the mixing of colours, preventing a distinct orange-red flame from being produced when testing the calcium iodide solution.
Step 3
Give the results of the tests.
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Answer
Copper sulfate solution: blue precipitate (blue solid).
Calcium iodide solution: white precipitate (white solid).
Step 4
Name the solution that would show the presence of sulfate ions when added to this mixture.
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Answer
Barium chloride solution would show the presence of sulfate ions.
Step 5
Name the solution that would show the presence of iodide ions when added to this mixture.
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Answer
Silver nitrate solution is used to test for iodide ions.
Step 6
Give the result of the test.
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Answer
The result for iodide ions is a yellow precipitate (solid).
