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Comparing Gas Tracers Through a Model Film 4 questions
Comparing Gas Tracers Through a Model Film
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A class models a thin film between two gas chambers. Equal starting amounts of tracer P and tracer Q are placed on the upstream side in separate runs. The downstream side initially has none of the tracer. Film area, temperature, and the starting partial-pressure difference for the tracer match in the two runs.
| Tracer | Amount upstream at start (mmol) | Amount found downstream after 5 min (mmol) |
|---|---|---|
| P | 5.0 | 1.5 |
| Q | 5.0 | 0.50 |
Question 1
Calculate the fraction of each starting tracer amount found downstream after five minutes.
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Question 2
What comparison is supported under the matched conditions?
- P transfers a larger fraction in five minutes.
- Q transfers a larger fraction in five minutes.
- Both transfer the same fraction.
- The larger fraction cannot be found without knowing the molar masses.
A student repeats Q with a different film and finds 1.5 mmol downstream. In that trial the starting difference in Q’s partial pressure across the film is larger than before.
Question 3
Explain why the new result alone cannot show that the different film lets Q transfer more readily.
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Question 4
Describe a matched test that isolates the film effect on Q. Identify which gas pressure difference should be kept the same and what to measure.
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