What actually happens when paint dries?

Question

Let’s say I buy an X amount of paint, which has a total mass of 5kg (or 5lb). I spread the whole content on my wall and 24hrs later the stuff has “dried” and my wall has taken on a new shade.

So chemically what has actually happened to that liquid that weighed 5kg/lb? Did it change phase to a solid, adhered to my wall, and then added 5kg/lb to the weight of the wall?

In: Chemistry

Answer 1

The details depend on what kind of paint, but in general, much of the wet paint is a liquid carrier (usually water and/or an organic solvent) that evaporates off.

So you are adding weight to the wall, but once dry, not as much as you applied.