Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: puppypower on 01/06/2016 23:23:25
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Does anyone know why the behavior of water is different from what is found in other materials. For example, no other material is commonly found as solid, liquid and gas.
As a gas, water is one of lightest known, as a liquid it is much denser than expected, and as a solid it is much lighter than expected when compared to its liquid form. Water can be extremely slippery and extremely sticky at the same time; and this 'stick/slip' behavior is how we recognize the feel of water.
There are currently 73 known anomalies, with other anomalies of water still remaining to be discovered, such as the possible link of water to room temperature superconductivity.
T. Scheike, W. Böhlmann, P. Esquinazi, J. Barzola-Quiquia, A. Ballestar and A. Setzer, Can doping graphite trigger room temperature superconductivity? Evidence for granular high-temperature superconductivity in water-treated graphite powder, Adv. M ater. 24 (2012) 5826-5831.
Another interesting example is, individual water molecules, in the liquid state, will expand when you cool the water, and will contract when you heat the water.
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Please change the subject of your post to a question and ask a science question in the main text
Thanks
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Please change the subject of your post to a question and ask a science question in the main text
Thanks
ditto
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How about; Why is water the most anomalous substance known, in the universe?
The term, known in the universe, is based on what science knows with hard fact, and not what might be postulated. Water is so simple, yet it is the most complex material known to man. There has been more research done with water, than any other material in the science literature. Yet few people are aware of just how unique water is. This uniqueness makes water a copartner with the organics of life. Organics have to conform to the water; water is the majority phase, leading to life.
I am not sure how to change the title, after the title has already been posted. Maybe someone can help.
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Ok, I've changed subject and opening line.
I'm not a chemist, but perhaps ChiralSPO can help.
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I would say that water's properties are 'extraordinary' or 'extreme' or 'exceptional' rather than 'anomalous.' In my mind, anomalous implies that the cause is unknown. Certainly water is exceptional in many ways.
I think most of them can be attributed to the unique hydrogen-bonding capability of water. Water molecules are unique in that they are good hydrogen bond donors and hydrogen bond acceptors, and each molecule has two hydrogens and two lone pairs, which allows the molecules to arrange in large networks. Ammonia is a better hydrogen bond acceptor than water is, but it is a poorer donor, and has an imbalance (each molecule has one lone pair, and three hydrogens); similarly, hydrofluoric acid is a better hydrogen bond donor and poorer acceptor than water, and is imbalanced the other way (three lone pairs and one hydrogen.) Therefore neither NH3 nor HF can reproduce the hydrogen-bonding networks that water can form. Hydrogen sulfide (H2S) is balanced like H2O in that it has two hydrogens and two lone pairs, but it forms much weaker hydrogen bonds than water does.
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Water is so simple, yet it is the most complex material known to man.
I would not say that water is the most complex material known to man. It is definitely more complex than one would think based on the simple molecular formula, due to intermolecular interactions and higher order organization and processes.
But as a diamagnetic, topologically simple material with localized molecular orbitals, and few degrees of conformational and vibrational freedom, I would say it still rates as 'not particularly complex' compared to the incredible variety of electronically complex materials.
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As ChiralSPO pointed out, hydrogen bonding is what give water it many properties. However, water although seemingly simple, has more anomalies than other known material. Water is not as straight forward as its simple formula indicates. Anomalies are odd behavior, based on the trends found in other materials.
For example, in liquid water, water molecules shrink as the temperature rises and expand as the pressure increases. This is considered anomalous or odd, since molecules typically expand when you heat them, and contract when you pressurize them.
It is expected that molecular bond lengths will increase and bonds will bend more as the temperature increases, giving rise to slight increases in the volume of individual molecules. However, as the temperature rises (> 4°C) the water molecules move away from each other and the hydrogen bonds weaken. This causes the O-H covalent bonds to shrink, strengthen and stiffen, so reducing the volume of individual water molecules [2044]. Thus, the water molecules shrink as the temperature rises.
As covalent bonds generally shorten under high pressure, a further anomalous change is that the O-H covalent bond length of water, in the liquid and solid phases, increases and weakens as the pressure increases. This is due to the hydrogen bond shortening under pressure. Thus the water molecules expand as the pressure rises.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fh_bond_temperature.gif&hash=3565fd16e9ba2d7f4667bf45a42524bc)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fh_bond_pressure.gif&hash=81b10ff47f441937390fc24d28c896ba)
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Here are a few more anomalies of water;
Water at 4C, will expand upon heating or cooling.
Liquid water can exist at very low temperatures, where it will freeze upon heating.
Water expands when it freezes and contracts when it melts.
The surface of water is denser than the bulk
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Here are a few more anomalies of water;
Water at 4C, will expand upon heating or cooling.
Liquid water can exist at very low temperatures, where it will freeze upon heating.
Water expands when it freezes and contracts when it melts.
The surface of water is denser than the bulk
Water is far from unique as far as materials that expand when they freeze: elemental bismuth, elemental silicon, acetic acid, and others all expand on crystallizing.
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Yes, the bonds in the molecules expand as the pressure increases, but overall the material is contracting significantly as the pressure increases, which is expected! The temperature dependence is also not surprising. In both cases, the intramolecular bonds and the intermolecular bonds are fighting for electron density--so the bond lengths will be inversely related. And the intermolecular bonds are weaker than the intramolecular bonds, so these lengths will be most sensitive to changes in temperature, and therefore will compensate more, leading to the opposite trend in the less sensitive intramolecular bonds.
As ChiralSPO pointed out, hydrogen bonding is what give water it many properties. However, water although seemingly simple, has more anomalies than other known material. Water is not as straight forward as its simple formula indicates. Anomalies are odd behavior, based on the trends found in other materials.
For example, in liquid water, water molecules shrink as the temperature rises and expand as the pressure increases. This is considered anomalous or odd, since molecules typically expand when you heat them, and contract when you pressurize them.
It is expected that molecular bond lengths will increase and bonds will bend more as the temperature increases, giving rise to slight increases in the volume of individual molecules. However, as the temperature rises (> 4°C) the water molecules move away from each other and the hydrogen bonds weaken. This causes the O-H covalent bonds to shrink, strengthen and stiffen, so reducing the volume of individual water molecules [2044]. Thus, the water molecules shrink as the temperature rises.
As covalent bonds generally shorten under high pressure, a further anomalous change is that the O-H covalent bond length of water, in the liquid and solid phases, increases and weakens as the pressure increases. This is due to the hydrogen bond shortening under pressure. Thus the water molecules expand as the pressure rises.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fh_bond_temperature.gif&hash=3565fd16e9ba2d7f4667bf45a42524bc)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fh_bond_pressure.gif&hash=81b10ff47f441937390fc24d28c896ba)
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The anomalies of water are connected to hydrogen bonding, which is unique among bonds.
Hydrogen Bond Definition: A hydrogen bond is a type of attractive (dipole-dipole) interaction between an electronegative atom and a hydrogen atom bonded to another electronegative atom. This bond always involves a hydrogen atom. Hydrogen bonds can occur between molecules or within parts of a single molecule. A hydrogen bond tends to be stronger than van der Waals forces, but weaker than covalent bonds or ionic bonds.
Hydrogen bonding also has some features of covalent bonding: it is directional and strong, produces interatomic distances shorter than the sum of the van der Waals radii, and usually involves a limited number of interaction partners, which can be interpreted as a type of valence. These covalent features are more substantial when acceptors bind hydrogens from more electronegative donors.
The self ionization in liquid water, that we call pH, may begin as hydrogen bonding between two water molecules based on dipole-dipole interactions. Iff the hydrogen bond becomes more directional, it begins to assume partial covalent character. Finally, it can become fully covalent, with the hydrogen now connected to a new water molecule. H2O + H2O ----> H3O+ + OH-.
The anomalies of water are usually connected to shifts between the dipole-dipole and the covalent natures of the hydrogen bond, with each having slightly different characteristics. Although both the dipole and covalent aspects of hydrogen bonding use electro-magnetic attraction; EM, the dipole-dipole is a little more slanted toward the electro-static side, while the covalent is a little more slanted toward the magnetic side.
As a way to visualize this, two electrons will repel each other based on electro-static considerations, since two negative charges will repel. The opposite spin electrons in atomic orbitals will attract, in spite of charge repulsion, because of magnetic considerations. A charge in motion, will produce a magnetic field, with opposite spin electrons allowing their magnetic fields to attract via the right hand rule.
The directional nature of the covalent aspect of hydrogen bonding reflects a shift in the hydrogen bond more toward the magnetic side of the EM force. The magnetic fields of the shared electrons, will need to align with the hydrogen, in ways that minimize the magnetic potential; very directional.
The magnetic and covalent aspect of hydrogen bonding allows hydrogen to mess with covalent bonds of molecules by impacting their magnetic order. In the case of pH, without the proper magnetic order for the bonding orbitals, covalent bonds can break quite easily. In fact, in liquid water, the average H2O molecule only lasts about 1 millisecond, before it swaps hydrogen.
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The ubiquity of water makes life possible on Earth. Water activity is anomalous and peculiar because its coherent oscillations connects two electronic configuration per molecule: The ground and excited configurations, where the molecular dipole moment (electromagnetic field) is trapped into a Coherence Domain (CD). Thus, water is considered the solvent of life by regulating osmosis and transporting thermal energy into cells.
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Water is also important to life for other reasons. For example, if you burn any organic material found in life, in the presence of oxygen gas, water will be one of the terminal products. Water is a very stable energy floor for life, since it is a stable final terminal product of organic combustion .
If you tried to start life with alcohols, methane or ammonia, or any organic solvent, these are not very stable energy floors, since these are all energy rich, compared to water. If life did evolve in other solvents, it would run the risk of burning its own solvent for energy. If this cellular state was stable, for all the various solvents, all roads will lead to water; only stable floor.
Although water is a very stable energy floor, it contains a powerful layer of secondary bonding activity connected to hydrogen bonding. Ammonia has this secondary hydrogen bonding layer too, but it is not a good long term energy floor. SO2 is a good energy floor but it lacks the secondary hydrogen bonding layer. Water can do both, better, than any two chemicals.
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Below are a few graphs, first of the melting point of water and other hydrides. In this first graph, notice water's melting point is about 100C higher than the extrapolated line, even though the water is the lightest of this top series and all but CH4 in the bottom series. In the second graph, all the hydrogen containing molecules and Ne, have the same molecular weight. These are compared in terms of freezing, boiling and critical points, with water once again, top in its class.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fmelting_points.gif&hash=21abed3548e1c325018c5e059fbc1ed4)
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww1.lsbu.ac.uk%2Fwater%2Fimages%2Fwater_isoelectronic.gif&hash=b1e06d0beb93f4ea4ee387cb95fb8ce4)
The reason for this is not just because of hydrogen bonding, but the fact that water can form four hydrogen bonds with itself. This creates a lot of stability, as reflected by the unusually high boiling, melting and critical points.
The ability of water to form four hydrogen bond is a critical part of life. Because water is so stable, due to four hydrogen bonds to other water, liquid water will form structuring not easily disrupted by thermal vibrations. As such, the organics of life, within water, have to accommodate this structural stability of water. The result is Water will segregate many organic things, if these cause its energy to increase. For example, lipids in water will be displaced by water into a bi-layer membrane. This is an example of what happens due to water's self bonding. The result is water will segregate the perfect shell for life.
Hydrophobic (water fearing) is a misnomer when it comes to organics and water, because water can form weak hydrogen bonds with any organic. The organics don't fear water, because these bonds are as strong as many organic interactions. The real push for hydrophobic (misnomer) separation is water is sort of narcissus, being self attracting, via its very four strong hydrogen bonds. The result is there is no room for the organics. The lipid bilayer is excluded from the bulk water; induced into the membrane, yet water can freely pass through the excluded membrane, since water can form weak hydrogen bonds with the lipids, if it has to.
Water can pass through carbon nanotubes, even though these are called hydrophobic interactions. The carbon sort of welcomes the water, but water prefers to stay with own, but will mingle if the conditions are right. The movement of water through carbon nanotubes is start and stop. The water tries to form hydrogen bonds with the carbon matrix, but it is not very good for water, so the hops to find a new place.
In terms of protein folding, the narcissus nature of water is so strong that even protein are induced into exact folds unaffected by statistics. These folds have a probability of 1.0. Water is useful to life because its need to self hydrogen bond into internal structuring, eliminates the randomness from protein structures.
I am not even sure why random is still taught for water based life, since this not been a realistic assumption since protein folding evidence was discovered over 50 years ago. Science sometimes prefers to crawl instead of walk.
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In terms of protein folding, the narcissus nature of water is so strong that even protein are induced into exact folds unaffected by statistics. These folds have a probability of 1.0. Water is useful to life because its need to self hydrogen bond into internal structuring, eliminates the randomness from protein structures.
no. no. no. no. no!
I agree with almost everything else you are saying (and excellent graphs by the way!), but this probability = 1.0 claim for protein folding is demonstrably wrong. If, as you say, the driving force behind protein folding is hydrogen bonding between water molecules, then why are proteins any different than any other organic molecules in water? I can tell that you are smart and knowledgeable, so why this particular hangup? Proteins mis-fold all the time, and this is a major problem both in biological systems and for scientists trying to study proteins. Why wouldn't proteins follow the laws of thermodynamics?