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Finding a Reading Time for a Salt Sensor 4 questions
Finding a Reading Time for a Salt Sensor
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A class tests a model sensor that reports dissolved salt concentration. The reference concentrations are 2.0 g/L and 8.0 g/L. The sensor has to report both within 0.2 g/L of their references. The class can wait at most six minutes for a reading.
| Time after placing probe (min) | Reading for 2.0 g/L (g/L) | Reading for 8.0 g/L (g/L) |
|---|---|---|
| 2 | 1.9 | 6.5 |
| 4 | 2.0 | 7.6 |
| 6 | 2.0 | 8.0 |
Question 1
What is the earliest listed time that meets the accuracy requirement for both references?
- Two minutes
- Four minutes
- Six minutes
- None of the listed times
Question 2
Why does the low reference alone give too little evidence for a two-minute reading rule?
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A student sees an unknown sample reading rise between minutes two and six and says the liquid must have gained dissolved salt.
Question 3
Use the high reference to give another explanation for the change in the unknown reading.
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Question 4
Describe a check using a second method that measures concentration quickly and accurately. State which result would support a slow response from the original sensor.
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