Is it possible to write pV=nRT as pV=mRT?

[superjose]

Hi people. I've been scratching my head for some time now...

My teacher of hydrology class keeps posting pV = mRT and I don't know why he is doing that.

He's trying to get the density of the air.

But I know it should go like this

pV =mRT/M...

Can someone clarify this for me?

:s

Thanks.

 

[jedishrfu]

Apparently its an alternative way of writing the formula given the mass:

http://crown.panam.edu/thermodynamics/homework/javascript/gaslaw1f.htm

and here:

http://www.roymech.co.uk/Related/Thermos/Thermos_Specific_heat.html

 

[Borek]

Probably he is using R that is specific for a given gas. Nonsense if you ask me, but I have seen it done in climate sciences.

 

[superjose]

Apparently its an alternative way of writing the formula given the mass:

http://crown.panam.edu/thermodynamics/homework/javascript/gaslaw1f.htm

and here:

http://www.roymech.co.uk/Related/Thermos/Thermos_Specific_heat.html

Probably he is using R that is specific for a given gas. Nonsense if you ask me, but I have seen it done in climate sciences.

Thanks a lot, it has solved my doubts! :D

 

[LudusRex]

Yes, it is possible to write pV=nRT as pV=mRT. In the ideal gas law, pV=nRT, the variables represent pressure (p), volume (V), number of moles (n), and gas constant (R). However, if we rearrange the equation to solve for mass (m) instead of number of moles, we get pV=mRT. This is because mass and number of moles are directly proportional, and we can use the molar mass (M) of the gas to convert between the two. Therefore, both equations are correct and can be used depending on what information is given and what is being solved for. It is important to understand the concept behind the equation and how the variables are related, rather than just memorizing the equation itself. I would recommend discussing this with your teacher to understand the reasoning behind using pV=mRT in this particular case.