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Checking an Unknown Salt With Two Tests 4 questions
Checking an Unknown Salt With Two Tests
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A classroom simulation compares dissolved salts. Reference test A makes a visible solid if chloride is present, and reference test B makes a visible solid if sulfate is present. The simulation uses a fresh portion for each test and gives the following records for pure salts.
| Reference salt | Test A | Test B |
|---|---|---|
| Sodium chloride | Solid | No solid |
| Potassium chloride | Solid | No solid |
| Sodium sulfate | No solid | Solid |
| Potassium nitrate | No solid | No solid |
Question 1
Which pure reference fits an unknown that gives no solid in test A and a solid in test B?
- Sodium chloride
- Potassium chloride
- Sodium sulfate
- Potassium nitrate
Question 2
Explain why the two tests cannot distinguish sodium chloride from potassium chloride.
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A second unknown gives a solid in both tests. It may contain a mixture of the reference salts. In this model a test still gives a solid when its target ion is present in a mixture.
Question 3
Propose a two-salt mixture from the reference list that fits the second unknown. Explain both results.
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Question 4
What should a third test detect to distinguish the two chloride salts in the possible two-salt mixtures? Explain why.
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