If water molecules can't expend, can it still freeze into ice?

Question

Someone told me that if water molecules can't expand then it can't freeze, will remain in liquid state even temperature falls well below freezing point. Is this true?

Answer 1

i'm pretty sure that person is wrong. Water turns into ice when the molecules come together. when they expand and separate from each other water goes into the gas state. hope i answered your question : )

if not sorry =(

Answer 2

Yes, but not for the reason you state.   Liquid water droplets can remain as liquid at below-freezing temperatures.  This has to do with lack of a non-water site to initiate freezing.  If you computed the space occupied by molecules in a volume of water, it would be mostly empty.  So expansion of the molecule is not the problem.  It has to do with the line up of water molecules when freezing starts.  In this line-up, the hydrogens of one molecule align with the oxygens of another.  In a liquid, the molecules don't align, and the water molecules can pack closer.  

Answer 3

I disagree with cattbarf. To freeze, water does need something to start the formation of the ice crystal lattice, but pressure has a even more of a significant effect on the phase of water (or for any substance for that matter). Water is different than most substances. When it freezes it becomes less dense by expanding. As always an increase in pressure favors the phase that occupies the smallest amount of space. In the case of water it is the liquid phase.

The reaction of freezing at equilibrium proceeds according to this equation:

H2O(liquid) --> H2O(solid)

My explanation also agrees with LeChatelier's principle that states: when a chemical system in equilibrium is disturbed, it reattains equilibrium by undergoing a net reaction that reduces the effect of the disturbance. In other words if you stress a system (add pressure) it will cause a shift in the amounts of reactants (liquid water) and products (solid water) to reduce the effect of the stress. Equilibrium will shift once again toward the phase with smaller volume.

H2O(liquid) smaller volume <-- H2O(solid) larger volume

I asked one of my chemistry professors and LeChatelier's principle applys in this case.

You couldn't be any more right when you say if water can't expand, it can't freeze to a certain extent. Now if the temperature is way below freezing and the pressure exerted on the water is suffecient, there will be a point at which the water will freeze. The reason it could freeze under the right conditions is that the lattice of the ice will take a more compact arrangment. If the pressure is very high and the temperature is very cold (Notice how I'm being vague because I don't know the exact temperature and pressure.) the water could freeze it just wouldn't expand. It would have a lattice structure not found under normal pressures.