What type of water is least dense?

1 Answer
Jun 28, 2017

Well, clearly, water vapor is the least dense... And we cannot just claim that without data. Consider the following.

rho_(H_2O(s)) = "0.9167 g/mL" at 0^@ "C" and "1 atm"

rho_(H_2O(l)) = "0.9970749 g/mL" at 25^@ "C" and "1 atm"

rho_(H_2O(g)) = "0.0005883 g/mL" at 100^@ "C" and "1 atm"

Gases are thus much less dense than their respective liquids. Usually about a thousand-fold...