If you like us, please share us on social media.
The latest UCD Hyperlibrary newsletter is now complete, check it out.

GeoWiki.png
ChemWiki: The Dynamic Chemistry E-textbook > Development Details > Approaches > Demos > Additional Demos > Dependence of Pressure on the Amount of Gas

Dependence of Pressure on the Amount of Gas

 

Chemical Concept Demonstrated

  • Pressure dependence on the amount of gas

Demonstration

  • Using the butane can, a gas is weighed and its pressure is measured.
  • Then, some of the gas is allowed to escape, and the measurements are made again.
  • This is done until the system and the atmospheric pressure come to equilibrium (meaning the pressure is zero).
 

Observations

As the gas is released from the can, the gauge pressure and mass of gas within the can will decrease. 
 

Explanation

Gas molecules create pressure by colliding with the surface within the can. Releasing the gas from the can decreases the number of gas molecules that are able to collide and create pressure.  The number of moles of gas within the can can be calculated using the atmospheric pressure, room temperature, and the volume of the butane can.  The molecular weight of an unknown gas can be estimated by the ratio of the mass of the gas in the can to the number of moles calculated.

Contributors

 

You must to post a comment.
Last Modified
10:28, 2 Oct 2013

Tags

Creative Commons License Unless otherwise noted, content in the UC Davis ChemWiki is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at copyright@ucdavis.edu. Questions and concerns can be directed toward Prof. Delmar Larsen (dlarsen@ucdavis.edu), Founder and Director. Terms of Use