[Twigg]

There's a graph showing the increase in the rate of condensation of water approaching dynamic equilibrium as it approaches the rate of vaporization. I'm curious what the function for the relation is assuming STP and a cylindrical closed system of a given volume. I imagine the textbook graph was using some sort of mean rate, but it doesn't specify and there are no graduations on the axes. It isn't for an assignment or anything, but I'll show my attempt at figuring it out:

Define g as the number of vapor molecules and q as the number of liquid molecules
Define t as time from the initiation of dynamic equilibrium
Then the instantaneous rate of condensation is dq/dt
dq/dt is the derivative of the rate of condensation for the domain of the rate of condensation
Given that dq/dt is equal to 0 when dynamic equilibrium is reached

And that's as far as I got. I'm not great at this. Any help?