Реферат на тему Properties Of Water Essay Research Paper What
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Properties Of Water Essay, Research Paper
What properties of water make it a unique material and an essential component of living matter?
Water is so common that it is easy to overlook the fact that it is an exceptional substance with many amazing qualities. With its properties, we can trace water s unique behavior to the structure and interactions of its molecules. Water is constructed of two hydrogen (H) and one oxygen (O). The hydrogen become + charged and the oxygen maintains a charge when they combine to form water. This is a single covalent bond. A covalent bond is the sharing of a pair of valence electrons by two atoms. The attraction is electrical; a slightly positive hydrogen of one molecule is attracted to the slightly negative oxygen of a nearby molecule. The two molecules are then held together by a hydrogen bonds. The hydrogen bonds hold the substance together, and this is called cohesion. Cohesion due to hydrogen bonding contributes to the transport of water against gravity in plants. Water reaches the leaves through vessels in the roots. Adhesion, the clinging of one substance to another, also helps. The water in the walls of the vessels helps counter the downward pull of gravity. This makes other substances extremely soluble in it, allowing important chemical reactions of metabolism and digestion to occur. Almost every chemical reaction that occurs in the body depends on water.
Water stabilizes air temperatures by absorbing heat from air that is warmer and releases stored heat to air that is cooler. An example of this would be an ice cube that is cooling a drink-it is adding coldness to the drink, but by absorbing heat as the ice melts. Hydrogen bonding gives water a high specific heat. Evaporative cooling is based on water s high heat of vaporization. Ice is less dense than liquid water because its more organized hydrogen bonding causes expansion into a crystal formation. Floating ice allows life to exist under the frozen surfaces of lakes and polar seas. Water is also a solvent because its polarity attracts it to charged and polar substances. When water molecules surround ions or polar substances, they dissolve and are called solutes. Hydrophilic substances have an affinity for water. Hydrophobic substances do not. One of its most important properties is its ability to dissolve many other substances. The versatility of water as a solvent is essential to living organisms. Water has many properties that make it a unique material and an essential component of living matter.