ABSTRACT
Mass transfer is mass in transit due to concentration differ-
ences. A species concentration gradient in a mixture con-
stitutes the driving potential for transport of that species.
Thus, mass transfer refers to the motion of species in a
mixture due to the presence of concentration gradients.
One example is the transfer of water vapor from a food
product to the dry air, as in drying. Another example is a
piece of sugar added to a cup of coffee that eventually
dissolves and diffuses to the solution.
