Does density change if some of the liquid evaporates between the time the liquid is delivered to the beaker and to the time it was measured?

Answer 1

Whether or not the density changes if some of the liquid evaporates between the time the liquid is delivered to the beaker and the time it is measured depends on the liquid. For almost all liquids, the answer is no because there was not enough time. Water will have a density of approximately 1 and if a small amount evaporates, it will still have the same density. If you had the beaker at 100C and the room at 0C and waited until the water was 4C, it would make a difference. If the water was at 40C and the room was at 30C, it would almost make no difference. A very few substances would undergo tremendous cooling. That would bring a corresponding increase in density.

Answer 2

Yes, if some of the liquid evaporates, the density of the remaining liquid will increase because the evaporated components are typically lighter than the liquid itself. This means that there is a higher concentration of the heavier components left behind, leading to a higher overall density.