When to use R
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 34
- Joined: Mon Jan 09, 2023 2:25 am
When to use R
Hi! Can anyone explain which R value we are supposed to use when solving for n in PV=nRT?
-
- Posts: 35
- Joined: Mon Jan 09, 2023 8:29 am
Re: When to use R
Hi it should just be the 8.3145 value typically, but you use any R value that cancels out the other units in your problem.
-
- Posts: 23
- Joined: Mon Jan 09, 2023 9:47 am
Re: When to use R
Use the gas constant (R) that corresponds to the units of pressure, volume, temperature, and the amount of substance (n). If pressure is in atm, volume is in L, and temperature is in K, use R=0.0821 L x atm/mol x K. If pressure is in Pa, volume is in m^3, and temperature is in K, use R=8.314 J/mol x K. Ensure that all units in the equation are consistent with the units of R used to obtain the correct value of n.
-
- Posts: 28
- Joined: Fri Sep 29, 2023 12:01 pm
Re: When to use R
in the ideal gas law equation PV=nRT, the variable n represents the number of moles of gas. the ideal gas constant R depends on the units you are using for pressure, volume and temperature. make sure that the units you are using for pressure, volume and temperature are consistent with the units of the gas constant R.
the values for R would be:
R=0.0821 kPa-1 mol-1 K-1 (used when pressure is in kilopascals, volume is in liters, and temperature is in kelvins)
R=0.0821 L atm-1 mol-1 K-1 (used when pressure is in atmospheres, volume is in liters, and temperature is in kelvins)
R=9.314 J mol -1 K-1 (used when pressure is in pascals, volume is in cubic meters, and temperature is in kelvins)
the values for R would be:
R=0.0821 kPa-1 mol-1 K-1 (used when pressure is in kilopascals, volume is in liters, and temperature is in kelvins)
R=0.0821 L atm-1 mol-1 K-1 (used when pressure is in atmospheres, volume is in liters, and temperature is in kelvins)
R=9.314 J mol -1 K-1 (used when pressure is in pascals, volume is in cubic meters, and temperature is in kelvins)
Who is online
Users browsing this forum: No registered users and 3 guests