Water anomaly: volume change
Water anomaly: volume change
(OP)
Hello all,
Can someone give me the exact volume change between water in 4°C and 0°C in percentage.
Thanks, Aharon
Can someone give me the exact volume change between water in 4°C and 0°C in percentage.
Thanks, Aharon





RE: Water anomaly: volume change
jproj
RE: Water anomaly: volume change
[(999.975/999.8426)-1]100 = 0.01324%.
By the way, water attains its maximum density at 3.98oC. The maximum density temperature tm changes with pressure, p in atmospheres as follows:
tm= 3.98-0.0225(p-1)
Shalom vehag (Pentecost) sameah.
NB: Above densities were taken from the CRC Handbook based on IUPAC data.
RE: Water anomaly: volume change
Thanks for your detailed reply.
How can you explain the phenomena: burst pipes and other full water containers because of freezing water? 0.01324% volume change, as you mentioned, can’t cause failures. Can it?
Hag Shamech to you too.
Aharon
RE: Water anomaly: volume change
RE: Water anomaly: volume change
OK, but my first question was: volume difference between water in 4°C and ice in 0°C and below.
Aharon
RE: Water anomaly: volume change
this seems to be one of the reasons why one generally tries to circumvent freezing of water.
sorry, can't give you better advice but hope that helps none the less,
chris
RE: Water anomaly: volume change
Regards
RE: Water anomaly: volume change
Ice at 0oC has a density of 916.9076 kg/m3.
The percentual change in volume from water at zero Celsius to ice at the same temperature (from tabulated values):
[(999.8426/916.9076)-1]100 = 9.0%.
By the way, if the water in the pipe in question was originally at, say, 25 Celsius the density change would be:
[997.048/916.9076)-1]100 = 8.7%
The reason for why is it that ice has a larger volume is that all the water molecules are held together by hydrogen bonds (O-H...O) resulting in an open three-dimensional network formed by six-membered rings of water molecules. Remember the 6-fold symmetry of snow flakes?
It takes 6 kJ/mol to melt ice to liquid water.
Freezing of water not only can cause bursting of water pipes, but also freeze-thaw cracking of rocks and concrete (potholes in streets and highways).
Fortunately, since winter ice is lighter than water it floats on lakes keeping the water underneath near 4oC which permits the survival of aquatic life. Hydrogen bonds are also responsible for the anomalously "high" (100 Celsius) boiling point of water (H2O) when compared with H2S, H2Se, and H2Te.
Try to imagine what life would be if water boiled at -80oC !...
Water is special in many other respects, but that's a subject for another thread.