Physlet Illustration: Boyle's Law

 

 

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A piston sits atop a cylinder filled with an ideal gas. The cylinder is surrounded by a constant temperature bath. Each grid in the animation represents a volume of 10 cm3. A digital temperature probe, which reads the gas temperature in °C, is attached to the cylinder. A digital pressure sensor, which reads the pressure in kPa, is also attached. Play the animation to push the piston down into the cylinder, and see how the volume and pressure change. The graph shows pressure (in kPa) vs. volume (in cm3). Can you verify Boyle's Law? How many moles of gas are in the cylinder?

Hints:

  1. What happens to the pressure as the volume of gas decreases?
  2. Pause the animation and determine P and V at some instant. Find the product PV.
  3. Pause the animation again and determine PV. Does this product remain constant?
  4. Convert P into Pa (i.e. N/m2) and V into m3.
  5. What is the temperature of the gas in Kelvins?
  6. Using PV = nRT, then, can you calculate the number of moles of gas?

Reference

See Walker, Section 17-1

Illustration written by Steve Mellema