Salt flux density in diffusion from seawater to freshwater

[olibee]

Homework Statement

this is a practice problem set

Relevant Equations

I know flux = concentration x velocity but I am not quite understanding if that is applicable here

What is the flux density of salt in a horizontal tube 10 cm in length connecting seawater (salinity = 30 g/l) to a tank of freshwater (salinity ~ 0) assuming no advection occurs?

 

[Orodruin]

An answer cannot be given based on only the data you have given. This is easy to argue with dimensional analysis. Is this the full question as stated? Are you allowed to look up tabulated values such as the diffusion coefficient of salt in water?

 

[Orodruin]

And you are right. Velocity * concentration does not apply because that is based on an advective flux and it is explicitly stated that there is no advection.