Question

As water gets colder, its density increases until it reaches "maximum density," freezes, and starts decreasing in density. At what temperature does maximum density occur?
A- 0 degrees c
B- 2 degrees c
c- 4 degrees c
d- 6 degrees c

Answer 1

Let's recall that water (all matter actually) has latent heat of fusion, which is the amount of energy required to freeze or melt water. Recall that this heat of fusion is removed at constant temperature. If the density of liquid water is inversely proportional to temperature, we can say that the maximum density of liquid water occurs at 0 C (any lower and we no longer have liquid water at atmospheric pressure).

Answer 2

@eashmore: Since this is water, shouldn't the max density actually be at 4C?

Answer 3

Indeed. I mistook the problem as comparing the density of water and ice at 0C.