2 replies to this topic

[guiromero]

Hello, I have a doubt in the following question about mass transfer: ________________________________________________________________________________________

 

"Mass transfer is the transport process in which a migration of one or more chemical species take place in a given system (solid, liquid or gas). The molecular mass transfer mechanism results from:"

 

[a] natural convection

 

[b] a temperature gradient

 

[c] mass transfer between phases

 

[d] mass transfer by forced convection

 

[e] vortex currents existing in fluid __________________________________________________________________________________________

 

Considering that the question is asking about MOLECULAR mass transfer, I suppose that the mechanism should be diffusion, not convection. The correct answer in the answer sheet is [b]. But I'm in doubt with it, because from what I know and from what I've researched, mass diffuison doesn't depend on a temperature gradient, despite that the diffusion coefficient depends on temperature (not a temperature gradient).

 

Option a) could not be possible, because it's about convection.

 

Option c) doesn't make sense in my opinion, because mass transfer should depend on the mechanism, not the opposite.

 

Option d) could also not be possible, because it's about convection.

 

Option e) could also not be possible, because as vortex currents happens on turbulent flow, they should also be related to convection.

 

 

Could somoene please clarify if my assumptions are correct or if the answer sheet is not incorrect.

 

 

Thanks a lot.

Edited by guiromero, 11 May 2023 - 02:29 PM.

[Pilesar]

Some academic questions do not make sense and the answers do not matter to anyone but the teacher. Pick your battles. This is not a question to be concerned about. Even if you have the correct answer, who would care?

[SilverShaded]

C is the only one thats related to diffusion.