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?
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
The flame colour produced by copper sulfate solution is green. This may also appear as blue-green in some tests.
Step 2
Explain why.
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
The student did not clean the metal wire between tests. Therefore, the copper sulfate (solution) may still be present, which mixes with the flame colour of calcium, masking the distinct orange-red flame colour expected.
Step 3
Copper sulfate solution:
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
The result of the test for copper sulfate solution when sodium hydroxide is added is a blue precipitate.
Step 4
Calcium iodide solution:
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
The result for calcium iodide solution with sodium hydroxide added is a white precipitate.
Step 5
Name the solution that would show the presence of sulfate ions when added to this mixture.
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
The solution that would show the presence of sulfate ions is barium chloride (solution).
Step 6
Give the result of the test.
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 result will be the formation of a white precipitate of barium sulfate.
Step 7
Name the solution that would show the presence of iodide ions when added to this mixture.
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
The solution that would show the presence of iodide ions is silver nitrate (solution).
Step 8
Give the result of the test.
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
The result will be the formation of a yellow precipitate of silver iodide.
