Large amounts of water can be given off by plants. It has

Chapter 14, Problem 14.23

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Large amounts of water can be given off by plants. It has been estimated, for instance, that a single sunflower plant can lose up to a pint of water a day during the growing season. Figure 14.16 shows a cross-sectional view of a leaf. Inside the leaf, water passes from the liquid phase to the vapor phase at the walls of the mesophyll cells. The water vapor then diffuses through the intercellular air spaces and eventually exits the leaf through small openings, called stomatal pores. The diffusion constant for water vapor in air is D 2.4 105 m2 /s. A stomatal pore has a cross-sectional area of about A 8.0 1011 m2 and a length of about L 2.5 105 m. The concentration of water vapor on the interior side of a pore is roughly C2 0.022 kg/m3 , whereas the concentration on the outside is approximately C1 0.011 kg/m3 . Determine the mass of water vapor that passes through a stomatal pore in one hour. Reason