posted by Luke .
in regard to the reverse freezing process of water(when it expands) and others molecules contract.. is it only water that does this or is it all the hydrogen bonded molecules?? ( N,O,F) NH3, H20 anf FH...my science teacher doesn't know the answer and i'd really like to know
No, water is not the only one that expands upon freezing. Type metal, the old stuff that was used in the older newspaper days (now MACs are used to write and I think the printing process is different too) expanded when it became solid. That was done so that the solid pieces would EXPAND to create a rigid network within the frame that was used to hold the individual type pieces. It has little to do with hydrogen bonding as type metal was an alloy of antimony, bismuth, and others. As to your question, however, I don't know the answer either. You could, however look up the density of, for example, NH3 just above and just below the freezing point and determine that for yourself.