Question

The mass of water vapor in the atmosphere (around 100 kg/m^2) is equivalent to a layer of liquid water how deep?

Answer 1

my hint is think of what you have to multiply the kg/m2 units to get a quantity in meters.

Answer 2

I'm guessing you mean a square meter projected through the entire atmosphere? Seeing as how the density of water is about 1000 kg/m^3 you would just need to divide the total mass of the water vapor by the mass of liquid water in one meter... (100 kg/m^2)/(1000 kg/m^3)=0.1 m approximately