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All constants are given and on the equation/formula sheet that Professor Lavelle allows us to use. Just be careful to use the right constant based on the unit of the pressure. There are different constants depending on if the pressure is measured in bars, atm, etc.
Any constants in this class will be provided on the constants and equations sheet. Dr. Lavelle doesn't expect us to remember these but rather how to apply them. As for your question, R is a constant that is given.
The constant of R is the ideal gas constant and you don't need to memorize anything regarding constants considering that they are all on the equations sheet. In terms of using the constant, the units tend to shift on whether you have the molar concentration (L*mol-1*K-1*atm)of something or you have the partial pressure of something (mol*L*atm/bar-1*K-1).
There are varying values for the constant R based on which unit you choose for partial pressure. However, since we calculate partial pressure in bar or atm most of the time, you would either use 8.20574x10^-2 (for atm) or 8.31446x10^-2 (for bar).
The gas constant is a constant. So any time a constant is mentioned it means it will always be the same specific number. An similar example is pi; it is always 3.14. So the gas constant is always equals 8.3144598 J/mol·K.
SamayaJoshi1A wrote:Why is the gas constant a constant? To me that part is a bit confusing because I would have thought the gas constant differs for each gas.
my understanding is that the gas constant has more to do with the state of the matter rather than its content if that makes sense? like it doesn't matter if its O2 or CO2 gas, but they both behave as gases and thats how the constant was found and why it can be universal.
Devan Nathu - 2H wrote:Where does the value for the gas constant come from? I understand that the value equals 8.3144598 J/mol·K, however how was this value calculated?
Avogadro's Law says that at STP (which is 1.00 atm and 0 degreesC), 1.00 mole of a gas takes up 22.4 L. If you rearrange the ideal gas law PV=nRT, you get R=PV/nT. Assuming we are at STP, R= (1.00atm)(22.4L)/(1.00mole)(273K) = 0.0821. For the other values of R, you can calculate it using the conversion factors (1 atm=101.3 kPa=760. mmHg) If you convert the units, the R value would be 8.3144598 J/mol·K.
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