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Checking Two Removals in a Gas Model 4 questions
Checking Two Removals in a Gas Model
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A classroom model puts two gases, R and S, into a sealed display chamber. At a fixed volume and temperature, the partial pressures of the gases add. The model can remove either gas completely without changing the amount of the other. Each test starts with a fresh copy of the same mixture.
| Condition | Chamber pressure (kPa) |
|---|---|
| Both gases present | 90 |
| All R removed | 30 |
| All S removed | 60 |
Question 1
What is the partial pressure of R in the original mixture?
- 30 kPa
- 60 kPa
- 90 kPa
- 120 kPa
Question 2
Explain how the two removal measurements can be used together to check the original pressure reading.
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The display tries a device that is intended to remove only R. From a fresh copy of the mixture, it lowers the pressure to 45 kPa at the same volume and temperature. A separate measurement confirms that the amount of S stayed the same.
Question 3
Calculate the partial pressure of R still present. Show how the independent check about S enters the calculation.
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Question 4
A student claims the device removed half the original R because it cut the total pressure in half. Evaluate the claim using the original and final R pressures.
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