The leaves of trees, oxygen is mostly generated in the chloroplasts in the palisade layer. The oxygen molecule then have to find their way out of the leaf through small openings in the leaf known as stomatal pores. The diffusion constant for oxygen in the air is about D = 20 μm^2/s. The length of a stomata is about 40 μm and its area is about 6 μm^2. If the density of oxygen molecules in the air outside of the leaf is 1.0 x 10^7 molecules/μm^3, and the density inside the spongy layer is 3.0 x 10^7 molecules/μm^3, calculate the number of oxygen molecules that will leave the leaf through a single stomata per second.