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Finding Isotope Patterns With the Same Mean 4 questions
Finding Isotope Patterns With the Same Mean
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A classroom detector models two samples of neon. It uses the rounded isotope masses 20, 21, and 22 u. Each sample record represents 100 atoms. The graphing display can show a separate peak for each isotope, with height proportional to its atom count.
| Sample | Count at 20 u | Count at 21 u | Count at 22 u |
|---|---|---|---|
| J | 50 | 0 | 50 |
| K | 25 | 50 | 25 |
Question 1
Calculate the mean atomic mass for both samples. Use the isotope counts.
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Question 2
Which single peak distinguishes K from J?
- A peak at 20 u
- A peak at 21 u
- A peak at 22 u
- A peak at the same mean as J
A student sees a mean of 21 u on another copy of the report and concludes that the detector must have counted some 21 u atoms.
Question 3
Use the data for one sample to evaluate that conclusion.
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Question 4
If the detector instead counted 200 atoms from K in the same proportions, explain what would happen to its calculated mean.
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