B, there are repulsion and attraction between molecules, both of which increase with the decrease of intermolecular distance, but the repulsion increases rapidly, so B is correct;

C, the particles suspended in the liquid are small enough, and the unbalanced impact of liquid molecules from all directions makes the particles move irregularly, which is Brownian motion, so C is correct;

D, on both sides of any line on the liquid surface, the interaction force is gravity, and its function is to make the liquid surface tight, so D is wrong;

So choose BC.

(2) During the experiment, the gas is compressed too fast, so the heat cannot be released quickly after the temperature rises, and the gas temperature will rise;

According to the ideal gas state equation PVT = C, PV=CT, where C is related to quality, so air leakage will reduce PV;

(3) The mass of water molecules is equal to the molar mass divided by Avon Garderot constant, so m =μna；;

The molar volume of water vapor in the standard state is equal to the molar mass of water vapor divided by the density of water vapor in the standard state, so V = μ ρ.

So the answer is: (1) BC; (2) the increase is smaller; (3)m=μNA，v=μρ。