Please help; will upvote if the answer helps with my studying:

A well-mixed open pond contains wastewater that is contaminated with methanol that is present at a concentration of 2.5gmole/m3. The pond is rectangular with dimensions of 300m by 75m, with air blowing across it in the direction shown. The temperature and pressure of the wastewater and air above are 15C and 0.98atm. The average wind speed above the water surface is 5m/s. What is the total methanol evaporation rate from the pond in units of gmole/s? The Henry's Law constant for methanol in water is 0.005gmole/m3atm and the methanol concentration in the bulk air flow well above the surface is approximately zero. You can use the diffusion coefficient from Table J.1, and assume that it varies with T1.75 (so you don't have to calculate those Ds )