3.3: Pressure and Gas Laws
- Page ID
- 66700
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Pressure
Pressure refers to the amount of force pushing against a given area.1 For this course, vapor pressure refers to the pressure exerted on a container from a substance that has been converted to its gaseous phase. An example of this is in a phenomenon called BLEVE, or Boiling Liquid Expanding Vapor Explosion. This occurs when a pressurized storage tank such as a propane tank is subjected to fire. The heat causes the liquified propane to vaporize, increasing the pressure inside the tank and weakening the integrity of the tank itself causing the tank to explode. You can check out this event in the video below.
This wordless video depicts the BLEVE phenomenon.
Video: "FEMA - BLEVE Boiling Liquid Expanding Vapor Explosion Demonstration Training Video" by The Federal Emergency Management Agency (FEMA), U.S. Department of Homeland Security. Public Domain. Retrieved from the Internet Archive.
Gas Laws
Boyle's Law
Boyle's Law states if the temperature of a gas is held constant, increasing the volume of the gas decreases its pressure.
Charles's Law
Charles's Law states if the pressure of a gas is held constant, increasing its temperature increases its volume.
Combined Gas Law
The combined gas law is a combination of Boyle’s law, Charles’s law, and Gay-Lussac’s law. The combined gas law states that when the amount of gas remains the same, pressure, volume and temperature can all change.
References
1. Adapted from Brainard, J. (2014). 4.2 Behavior of Gases. In CK-12 Physical Science For Middle School. https://www.ck12.org/book/ck-12-physical-science-for-middle-school/r2/section/4.2/. Licensed CC BY-NC.