Constant R for gas laws has two values
8.314 and 0.08206
Which one do I use in what situation?
8.314 and 0.08206
Which one do I use in what situation?
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0.0821 is used when you're working in L, atm, mol, and K units.
The correct form is 0.0821 L * atm / mol * K
The purpose of using this is so that your units will cancel and you'll be left with the desired unit.
1.987 is used when you're working in Cal, mol, and K.
The correct form is 1.987 Cal / mol * K
8.314 is used when you're working in J, mol, and K.
The correct form is 8.314 J / mol * K
8.314 is also used when working in m^3, Pa, mol, and K.
The correct form is 8.314 m^3 * Pa / mol * K
Finally, 62.36 is used when working in L, torr, mol, and K.
The correct form is 62.36 L * torr / mol * K
So how do you know which one to use? Like I had said above, the purpose of this is to basically get your units to cancel out. So if you have three values that share similar units as one of the numbers above, then use that number. If you have two values with similar units, but one is different, then convert the other unit to the correct unit.
I would highly recommend writing down the the numerical values in various units that I listed; it can be very helpful when studying and doing problems!
The correct form is 0.0821 L * atm / mol * K
The purpose of using this is so that your units will cancel and you'll be left with the desired unit.
1.987 is used when you're working in Cal, mol, and K.
The correct form is 1.987 Cal / mol * K
8.314 is used when you're working in J, mol, and K.
The correct form is 8.314 J / mol * K
8.314 is also used when working in m^3, Pa, mol, and K.
The correct form is 8.314 m^3 * Pa / mol * K
Finally, 62.36 is used when working in L, torr, mol, and K.
The correct form is 62.36 L * torr / mol * K
So how do you know which one to use? Like I had said above, the purpose of this is to basically get your units to cancel out. So if you have three values that share similar units as one of the numbers above, then use that number. If you have two values with similar units, but one is different, then convert the other unit to the correct unit.
I would highly recommend writing down the the numerical values in various units that I listed; it can be very helpful when studying and doing problems!
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They are in different units...
R = 8.314 J/mol K, so you typically use this when energy calculations are involved such as enthalpy, entropy and free energy.
R = 0.08206 L Atm / K mol, so you would us this typically when you are looking to solve for pressure, volume, temperature or moles of gas given the other parameters
8.314 J/mol K = 0.08206 L Atm / K mol, its just a matter of converting the units
R = 8.314 J/mol K, so you typically use this when energy calculations are involved such as enthalpy, entropy and free energy.
R = 0.08206 L Atm / K mol, so you would us this typically when you are looking to solve for pressure, volume, temperature or moles of gas given the other parameters
8.314 J/mol K = 0.08206 L Atm / K mol, its just a matter of converting the units