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Water

Water.

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Water

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  1. Water

  2. Water is a common chemical subtance that is essential for the survival of all known forms of life.In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice , and a gaseous state, water vapour or steam . Water covers 71% of the earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapour, clouds (formed of solid and liquid water particles suspended in air), and precipitation.

  3. WATER ,ICE & VAPOUR Water has the second highest specific heat capacity of any known chemical compound, after ammonia, as well as a high heat of vaporization (40.65 kJ mol−1), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties allow water to moderate Earth's climate by buffering large fluctuations in temperature. The specific enthalphy of fusion of water is 333.55 kJ kg−1 at 0 °C. Of common substances, only that of ammonia is higher. This property confers resistance to melting upon the ice of glaciers and drift ice. Before the advent of mechanical refrigeration, ice was in common use to retard food spoilage.

  4. ELECTROLYSIS Water can be split into its constituent elements, hydrogen and oxygen, by passing an electric current through it. This process is called electrolysis. Water molecules naturally dissociate into H+ and OH− ions, which are pulled toward the cathode and anode, respectively. At the cathode, two H+ ions pick up electrons and form H2 gas. At the anode, four OH− ions combine and release O2 gas, molecular water, and four electrons. The gases produced bubble to the surface, where they can be collected. The standard potential of the water electrolysis cell is 1.23 V at 25 °C.

  5. WATER AS A SOLVENT Water is also a good solvent due to its polarity. Substances that will mix well and dissolve in water (e.g. salts) are known as “hydrophilic" (water-loving) substances, while those that do not mix well with water (e.g. fats and oils), are known as “hydrophobic" (water-fearing) substances. The ability of a substance to dissolve in water is determined by whether or not the substance can match or better the strong attractive forces that water molecules generate between other water molecules. If a substance has properties that do not allow it to overcome these strong intermolecular forces, the molecules are “pushed out" from the water, and do not dissolve.

  6. Types of water Water can appear in three states; it is one of the very few substances to be found naturally in all three states on earth. Water takes many different forms on earth: water vapour and clouds in the sky; sea water and rarely ice bergs in the ocean; glaciers and rivers in the mountains; and the liquid in aquifers in the ground.

  7. Water can dissolve many different substances, giving it different tastes and odors. In fact, humans and other animals have developed senses which are, to a degree, able to evaluate the probability of water, avoiding water that is too salty or putrid. Humans also tend to prefer cold water to lukewarm; cold water is likely to contain fewer microbes. The taste advertised in spring water or mineral water derives from the minerals dissolved in it, as pure H2O is tasteless

  8. H2O Water (H20, HOH) is the most abundant molecule on Earth's surface, composing of about 70% of the Earth's surface as liquid and solid state in addition to being found in the atmosphere as a vapor. It is in dynamic equilibrium between the liquid and gas states at standard temperature and pressure. At room temperature, it is a nearly colourless (with a hint of blue),tasteless, and odorless liquid.

  9. WATER IS PRECIOUS! Water is life ! It is a precondition for human, animal and plant life as well as an indispensable resource for the economy. Water also plays a fundamental role in the climate regulation cycle. Protection of water resources, of fresh and salt water ecosystems and of the water we drink and bathe in is therefore one of the cornerstones of environmental protection in Europe. The stakes are high and the issues transcend national boundaries and concerted action at the level of the EU is necessary to ensure an effective protection.

  10. PHYSICS & CHEMISTRY OF WATER Water is the chemical substance with chemical formulaH2O: one molecule of water has two hydrogenatomscovalentlybonded to a single oxygen atom. [4] Water is a tasteless, odorless liquid at ambient temperature and pressure, and appears colorless in small quantities, although it has its own intrinsic very light blue hue. Ice also appears colorless, and water vapor is essentially invisible as a gas.[5] Water is primarily a liquid under standard conditions, which is not predicted from its relationship to other analogous hydrides of the oxygen family in the periodic table, which are gases such as hydrogen sulfide.

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