Consider air in a closed, cylindrical container with its axis vertical and with opposite ends maintained at different temperatures. Assume that the total pressure of the air is uniform throughout the container.

(a) If the bottom surface is colder than the top surface, what is the nature of conditions within the container? For example, will there be vertical gradients of the species (O2 and N2) concentrations? Is there any motion of the air? Does mass transfer occur?

(b) What is the nature of conditions within the container if it is inverted (i.e., the warm surface is now at the bottom)?