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Tracking Composition as a Mixture Evaporates 4 questions
Tracking Composition as a Mixture Evaporates
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A display models a liquid mixture containing 40 particles of ethanol and 40 particles of water. A sample of 20 vapor particles leaves the liquid and is collected. No chemical reaction occurs. The display can count each type in the collected sample.
| Collected vapor | Ethanol particles | Water particles |
|---|---|---|
| First sample | 15 | 5 |
Question 1
Which statement compares the first vapor sample with the initial liquid?
- The vapor has a greater fraction of ethanol.
- The vapor has the same ethanol fraction.
- The vapor contains no water.
- The vapor has a smaller fraction of ethanol.
Question 2
Calculate the fraction of the remaining liquid particles that are ethanol.
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Question 3
A student says the first vapor sample proves that only ethanol evaporates. Evaluate the claim using both particle counts.
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The display collects a second vapor sample after the remaining liquid changes composition. The second sample contains 10 ethanol particles and 10 water particles.
Question 4
Compare the second sample’s ethanol fraction with the fraction in the liquid just before it was collected. Explain whether the second vapor still contains a greater fraction of ethanol than its source liquid.
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