Why Does Water Rise in a Test Tube When a Candle Burns?

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SUMMARY

When a candle burns in a test tube submerged in water, the candle consumes oxygen, leading to its extinguishment. This process creates a vacuum as the temperature rises and the volume of gas decreases, causing water to rise into the test tube. The carbon dioxide produced during combustion dissolves in the water, further reducing gas volume. This phenomenon is a clear demonstration of the relationship between temperature, pressure, and gas volume as described by the ideal gas law.

PREREQUISITES
  • Understanding of basic chemistry concepts, particularly combustion.
  • Familiarity with the ideal gas law and its implications.
  • Knowledge of gas solubility in liquids, specifically carbon dioxide in water.
  • Basic principles of thermodynamics related to temperature and pressure.
NEXT STEPS
  • Research the ideal gas law and its applications in real-world scenarios.
  • Explore the process of combustion and the products formed during burning.
  • Investigate the solubility of gases in liquids, focusing on carbon dioxide.
  • Study thermodynamic principles, particularly how temperature affects gas volume and pressure.
USEFUL FOR

Students of chemistry, educators teaching combustion and gas laws, and anyone interested in the physical principles behind chemical reactions and gas behavior.

rdgt3000
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Why is it that when you place a test tube over a burning candle in a peatree dish with water, that the candle goes out and then the water from the dish rises into the test tube. Mainly what are the reasons that the water rises. I am kind of going with the "temperature and pressure are related" idea but I am not quite sure if that is right. Thanks for the help!
 
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My guess is that by closing up the system, the temperature increases, compensated by the dramatic decrease in volume.
 
Candle uses all oxygen and goes off. Produced carbon dioxide solves in water and that's why gas volume in the test tube decreases - and water goes up.
 
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