Water anomaly: volume change 4

[adavidi]

Hello all,
Can someone give me the exact volume change between water in 4°C and 0°C in percentage.

Thanks, Aharon

 

[jproj]

Look in any thermodynamics textbook with a steam table. Properties of water and its density are very common and can undoubtedly be found online too.

jproj

 

[25362]

Aharon, the tabulated standard densities of liquid water are: @ 0^oC, 999.8426; @ 4^oC, 999.9750 kg/m³. From these you can estimate the volume change:

[(999.975/999.8426)-1]100 = 0.01324%.

By the way, water attains its maximum density at 3.98^oC. The maximum density temperature t_m changes with pressure, p in atmospheres as follows:

t_m= 3.98-0.0225(p-1)

Shalom vehag (Pentecost) sameah.

NB: Above densities were taken from the CRC Handbook based on IUPAC data.

 

[adavidi]

25362,
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

 

[phex]

the volume difference 25362 mentioned is between liquid water of 4 °C and liquid water of 0 °C. when the water solidifies, the solved gases (in part) are set free and form gas bubbles (thats why ice is white) which contributes majorly to volume change. this is what makes the pipes burst.

 

[adavidi]

Phex,
OK, but my first question was: volume difference between water in 4°C and ice in 0°C and below.
Aharon

 

[phex]

i don't think there is an exact number available on how large a change there is. when regarding icecubes at home, they aren't the same size when they are frozen, even if the liquid water was distributed perfectly even. it depends on the amount of gas in solution, what gases, how fast they dissolute, how much gas goes off before being caught in the solid water....
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

 

[ardilesd]

Ice density should be around 0,92 , according to Perry 6th Edition , thats explains a almost 10 % increase in volume.
Regards

 

[25362]

Aharon, if you look again you'll see your original question didn't say a word about ice, only water was mentioned!

Ice at 0^oC 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 4^oC 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 -80^oC !...

Water is special in many other respects, but that's a subject for another thread.