Week #6: (10/10,15) Boyle's Law & The Ideal Gas Law

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Week #6: (10/10,15) Boyle's Law & The Ideal Gas Law

Post by rjagodowski » Wed Oct 09, 2019 9:52 pm

Here's a link about Boyle's Law from Wikipedia to get us started. Also from Wikipedia, some Boyle's Law Demonstrations. Boyle's law is presented on Page 280 in Chapter 15 of the text.

The Ideal Gas Law from:


The Ideal Gas Law is often written as
P V = n R T
P is the pressure of the gas,
V is the volume of the gas,
n is the amount of substance of gas (in moles),
R is the ideal, or universal, gas constant, equal to the product of the Boltzmann constant and the Avogadro constant,
T is the absolute temperature of the gas.

The Ideal Gas Law requires that all units be in absolute measurements, meaning that they must be greater than or equal to zero. No negative numbers. For temperature scales, both the common Fahrenheit and Celsius scales have negative temperatures, so they cannot be used in Ideal Gas Law calculations. Instead, the Rankine and Kelvin scales are used. Both of these have 0 degrees as "absolute zero", the temperature at which all atomic/molecular motion has stopped. The Rankine scale then defines one degree Rankine as equal to one degree Fahrenheit. The Kelvin scale defines one degree Kelvin as equal to one degree Celsius.

Likewise, pressures must be measured using an absolute scale. So all pressures must be measured such that a perfect vacuum is 0 and any additional atoms/molecules added will create a positive pressure.

A link explaining the Rankine Temperature Scale. This is an "absolute" scale where the lowest temperature is 0 degrees (known as absolute zero).

Here's a chart showing common temperatures measured in the different scales: Kelvin, Rankine, Fahrenheit, Celsius.
Temperature Conversion Charts.jpg
Temperature Conversion Charts.jpg (83.06 KiB) Viewed 83 times
Here's a link to a Demonstration of the Ideal Gas Law. NOTE: This demo uses Java, so if you are concerned about running Java apps on your computer, run this simulation on somebody else's computer! :) CORRECTION: Apparently the app has been updated to HTML, so the Java security issues are no longer an issue.

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