Has there been an improved understanding of water ?

Discussion in 'Chemistry' started by river, Aug 16, 2013.

  1. wellwisher Banned Banned

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    An interesting state of water is water at and above its critical point. The critical point is where the boundary between the gaseous and liquid states gets fuzzy. This occurs at 647 K (374 °C; 705 °F) and 22.064 MPa (3200 PSIA or 218 atm) for water. Water becomes a dense fluid that is neither gas or liquid, but is sort of both at the same time. It acts like a gas, but because of pressure it is as dense as a liquid. Supercritical water becomes a very aggressive solvent for minerals, rocks and organics.
     
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  3. exchemist Valued Senior Member

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    .....Also an increasingly important working fluid in high efficiency powergen:

    http://www.netl.doe.gov/technologies/coalpower/advresearch/Ultrasupercritical.html

    Seems you can get >45% thermal efficiency with Ultra Super Critical steam turbines, nowadays, which is not that far behind the best low-speed diesels (50%).
     
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  5. wellwisher Banned Banned

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    The critical point is where the boundary between gaseous and liquid water gets fuzzy. The water behaves similar to a gas (individual molecules) but exists at densities that approach that of liquid water.

    If we continue to heat and pressurize the supercritical water, eventually a new state of water forms called superionic. This is relatively new understanding fo water. This phase of water becomes a solid. The oxygen of water, as oxide, occupies the positions within the solid crystal lattice (negative ionic lattice) with the hydrogen protons (positive ions) sort of free to move about. This is nasty stuff. If we had a piece of superionic solid water and the pressure was to drop to below the phase boundary, it explodes like TNT. At the conditions of the earth's mantle, due to the extra mass and weight of the minerals in the mantle, superionic water can form.
     
    Last edited: Sep 5, 2013
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  7. wellwisher Banned Banned

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    If we continue to heat and pressurize water, the solid superionic water, above will eventually become an ionic fluid. It goes from fluid at critical conditions to a solid at superionic and then back to a fluid again. In the lab, this ionic fluid can occur at conditions similar to what is found in the outer core of the earth. The fluid around the earth magnetic core contains ionic fluid water.

    If we add even more pressure and temperature, water now becomes a metallic solid, which is now a good conductor of electricity. In the lab this has been demonstrated at conditions similar to the earth's solid metallic core.

    The way they do such experiment is with water switches, into which they apply huge amounts of electric current. One experiment used the equivalent of the world's electricity for a nanosecond. They store it in capacitors and then bleed it. Water is normally a poor conductor of electricity. When you apply this high level of electricity, the water instantly vaporizes to create an extreme pressure shock wave. You will then notice the changes in the electrical conduction as the electricity works it way through the switch. This in conjunction with simulations allows them to plot out the phases and phases boundaries of extreme water.
     
  8. river

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    By the way I did discuss my experiment with a hydrogen researcher

    He was intrigued , and it would cost me $150,000 to do so , damn

    He also suggested I search to find if the experiment had been done already , by doing a boolean search ( never heard of this search ) , it wouldn't have surprised him

    So far my search has turned up zero
     
  9. Forceman May the force be with you Registered Senior Member

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    Water

    The people at the University of Florida are discovering more about water and the properties of water.
     
  10. exchemist Valued Senior Member

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    ????.....and.....???
     
  11. wellwisher Banned Banned

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    An interesting property of water is the unusually high heat capacity of water. Heat capacity, or thermal capacity, is the amount of heat required to change the temperature of an object or body by a given amount, say one degree. To raise the temperature of water one degree takes more heat that most materials.

    Water vapor has more than double the heat capacity of gases like oxygen, nitrogen and carbon dioxide. This heat storage ability of water makes water the major heat sink within the atmosphere. Water has the extra energy capacity that drives weather and climate.

    Here is the scenario. The sun heats the earth's surface and atmosphere. The very high heat capacity of the water causes extra energy to be stored in the oceans, lakes and rivers, as well as in the atmosphere because the water can store extra heat per one degree rise. This heat capacity moderates the temperature fluctuations on the earth, since there is a lot of extra heat storage to act as a buffer. The ocean will freeze much later than the land due to heat capacity.

    The evaporation of water into the atmosphere, increases the amount of energy within the atmosphere. The water becomes the engine of weather which is powered by the sun.
     
  12. wellwisher Banned Banned

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    Water is the second most abundant molecule in the universe behind only hydrogen gas, which is H2. Because of the abundance and unique properties of water, water is one of the main starting materials used to make stars. Space water, as ice, collects due to gravity. The pressure due to gravitational work heats the ice until it melts within the core of the forming star. When water melts, it contracts by 10%. This sudden drop in volume, causes a collapse hammer effect as more and more ice changes into water. If water behaved normal there would be no collapse hammer effect.
     
  13. benzoic Registered Member

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    What do you mean?
    What do you have a better understanding of the water?
    You should express yourself clearly.
     
  14. arauca Banned Banned

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    Abstract
    We demonstrate that the Mpemba paradox arises intrinsically from the release rate of energy initially stored in the covalent H-O part of the O:H-O bond in water albeit experimental conditions. Generally, heating raises the energy of a substance by lengthening and softening all bonds involved. However, the O:H nonbond in water follows actively the general rule of thermal expansion and drives the H-O covalent bond to relax oppositely in length and energy because of the inter-electron-electron pair coupling [J Phys Chem Lett 4, 2565 (2013); ibid 4, 3238 (2013)]. Heating stores energy into the H-O bond by shortening and stiffening it. Cooling the water as the source in a refrigerator as a drain, the H-O bond releases its energy at a rate that depends exponentially on the initially storage of energy, and therefore, Mpemba effect happens. This effect is formulated in terms of the relaxation time tau to represent all possible processes of energy loss. Consistency between predictions and measurements revealed that the tau drops exponentially intrinsically with the initial temperature of the water being cooled.

    Read more at: http://phys.org/news/2013-11-faster-cooler.html#jCp
     
  15. exchemist Valued Senior Member

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    Thanks for this. I've read it and it seemed to be nonsense, being full of elementary errors in understanding about the kinetic theory of heat and chemical bonding. Furthermore the "Mpemba" effect or paradox appears to have been NEVER reliably reproduced. It remains controversial and may not exist at all, except as an occasional artifact of the experimental conditions.

    (This Singapore paper has not been peer-reviewed. That's the nature of this "arxiv" web publishing service. If it ever IS reviewed and published in a reputable journal, I'll bet it will have been rewritten substantially.)
     
  16. wellwisher Banned Banned

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    Cold water forms clustering which makes it hard for the water molecules to rearrange to form the expanded hexagonal network of ice; supercooling. With hot water, these clusters are less common, and if we cool the water in a certain way, we can bypassed the cold water clustering, allowing ice to form easier.
     
  17. wellwisher Banned Banned

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    Deeply supercooled liquid water can be produced from glassy amorphous ice between -123 °C and - 149 °C. This behavior is particularly anomalous as the liquid (deeply supercooled water) is a 'strong' liquid that changes to crystalline solid (cubic ice) on increasing the temperature whilst keeping the pressure constant. Such a 'strong' to 'fragile' (Arrhenius to non-Arrhenius) change in a liquid is not normal.

    Deeply supercooled water exists in the liquid state where it appears to be too cold to diffuse sufficiently quickly to crystallize. You need to add heat to speed up the molecules so they can move better and form ice.

    Water has 69 known anomalies.
     
  18. river

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    9,791
    Watch this video on water by Gerald Pollack , very interesting

    http://www.youtube.com/watch?v=_VcLel9w11g

    By the way , when going to part 2 , and click on it you may get a snowy screen , just refresh , then the video will play , there a few videos to watch

    Enjoy

    river
     
  19. exchemist Valued Senior Member

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    It's unreasonable to expect readers to watch a 30 minute video clip. If you can provide a summary of the main points, then maybe we can discuss.
     
  20. river

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    An hour perhaps would be unreasonable , but a half an hour , I don't think is

    And quite frankly if you have a true interest upon the subject you will view the video

    river
     
  21. exchemist Valued Senior Member

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    The problem is you can't be bothered to explain, even in summary, what the "subject" in question is.

    Without that, you cannot expect to pique my interest, or that of most others.

    That's all.
     
  22. river

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    9,791
    Then you will be ignorant of whats going on in the study of water up to now

    And as I said , if you have a true interest , you will watch the video , if not , you won't

    Therefore your voice on the thread means nothing
     
  23. arauca Banned Banned

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    From what I got , Wather is composed of Hydronium ion and the counterpart , this can be seen and measure by observing with a dye so called an acidic layer , and this part is quiet different from the bulk water .
    I can understand that the liquid which is in contact with any surface is going to show different property then the bulk , because the surface will atract the polarity to interact and so there will be establushed a so called doublelayer.
    The presentation is quiet interesting , but the extrapolation can be vied with some challenge .
     

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