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Checking a Shifted Chloride Detector 4 questions
Checking a Shifted Chloride Detector
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A model detector displays the mass number of isolated singly charged negative ions. An instrument offset shifts the reading by the same amount for every ion. The class tests a reference of bromine-79 as bromide ions and a chloride sample known to contain chlorine-35 and chlorine-37.
| Record | First displayed number | Second displayed number |
|---|---|---|
| Bromide reference | 80 | — |
| Chloride sample | 36 | 38 |
Question 1
Which detector correction makes both records consistent with the known samples?
- Subtract 1 from every displayed number
- Add 1 to every displayed number
- Subtract 2 only from the chloride readings
- Leave every displayed number as shown
Question 2
Explain why the separation between the two chloride readings alone cannot reveal this calibration shift.
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The detector software is corrected. A new test shows peaks at 35 and 37. It also reports 75 ions at the first peak and 25 at the second.
Question 3
Use the periodic table to compare the numbers of protons, neutrons, and electrons in the two chloride ions.
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Question 4
Explain which corrected record shows that the two isotopes occur in different amounts in this sample.
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