A stearic acid solution (molar mass 284 g/mol) is added drop wise into a water surface using a dropper pipet. It requires 17 drops of solution to form a monolayer on the water that ahs a surface area of 78.5 cm squared. Calculate the expirementle value of Avagadros number given the following data: Assume each stearic acid molecule ocupies an area of 20.5 A squared and that there are no spaces between molecules in the monolayer.

Data: Dropper pipet calibration is 90 drops. Stearic acid solution is 9.75 times ten to the negetive fifth g/ml 1 cm is 10 to the eighth A.

I have begun this problem by using the mass to mole and mass to mass ratios but i messed up and i do not know how to start it. Please would someone work out the problem for me includingshowing their work I would really apreciate it thanks a lot.