A laboratory apparatus to measure the diffusion coefficient of vapor-gas mixtures consists of a vertical, small-diameter column containing the liquid phase that evaporates into the gas flowing over the mouth of the column. The gas flow rate is sufficient to maintain a negligible vapor concentration at the exit plane. The column is \(200 \mathrm{~mm}\) high, and the pressure and temperature in the chamber are maintained at \(0.25 \mathrm{~atm}\) and \(320 \mathrm{~K}\), respectively.

Calculate the expected evaporation rate \(\left(\mathrm{kg} / \mathrm{h} \cdot \mathrm{m}^{2}\right)\) for a test with water and air under the foregoing conditions, using the known value of \(D_{\mathrm{AB}}\) for the vapor-air mixture.