A 410 mL spherical flask contains 0.075 mol of an ideal gas at a temperature of 335 K. What is the average force exerted on the walls of the flask by a single molecule?

how do you find the average force? Do I use pv=nrt equation?

PV = nRT

You know V, n, and T. You can look up R and calculate the pressure. After that you can figure out how many molecules using Avogadro's number and the number of moles present (0.075). You divide the pressure by the total number of molecules to figure out the pressure exerted by a single molecule.

Let me google "Avogadro's number" for you (http://www.lmgtfy.com/?q=Avogadro%27s+number)

One more step - once you have the average pressure you need to multiply by the surface area of the vessel to get the average force per molecule exerted on the walls.