Water properties

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Water properties

  1. 1. WATER PROPERTIES<br />Water has a number of important properties below are due to the hydrogen bonds in water :<br />Water as Universal Solvent<br />High Specific Heat Capacity of Water<br />High Latent Heat of Vaporisation of Water<br />Low Viscosity<br />High Cohesion and Adhesion of Water<br />Lower Density in Solid State<br />The Ionisation of Water<br />
  2. 2. NOOR ASYIKIN BT KAMARAZAMAN D20091034860SITI SARAH BT MOHD SAIFUDDIND20091034843NURUL HUSNA BT ALIASD20091034858SYARIFAH ROQAIYAH BT MUD PUADD20091034851ZAINAB FASIHAH BT MUHAMAD SUKARDID20091034842SITI SHAHIDA BT MOHD AZIRID20091034836<br />
  3. 3. 1) Water as Universal Solvent<br /> good solvent due to its polarity.<br />Polar water molecules attract each other as well as ions and other polar molecules.<br />Because of this attraction, water can dissolve many ionic compounds.<br />Polar molecules such as salt,sugars and amino acids are hydrophilic while non-polar molecules such as lipids are hydrophobic.<br />This property allow only a certain molecules to dissolve in water while preventing others from entering the cell.<br />
  4. 4. 2) High Specific Heat Capacity of Water<br />Specific heat of a substance is the amount of heat that must be absorbed or lost by 1 gram of that substance in order to change its temperature by 1°C.<br />The high specific heat of water is due to the high energy required to break the hydrogen bonds that hold the liquid together.<br />As such, a large input of thermal energy is required to break these bonds before the individual molecules can move freely.<br />
  5. 5. This property allows water to absorb or lose large amounts of heat without undergoing correspondingly large changes in temperatures. Thus:<br />It enables organisms with a high content of water to maintain a relatively constant internal temperatures.<br /> It allows lakes and oceans to maintain a relatively constant temperatures.<br />
  6. 6. 3) High Latent Heat of Vaporisation of Water<br />Latent heat of vapourisation is the energy required to break its hydrogen bonds to changes its state from liquid to water.<br />Water has a relatively high latent heat of vaporisation ( 586 calories/ g) when compared with other substances.<br />Evaporation of water from a surface causes cooling of that surface as heat is removed.<br />This is used as a cooling mechanism in animals<br /> ( sweating and panting ) and plants ( transpiration).<br />As water evaporates it extracts heat from around it, thus cooling the organism.<br />
  7. 7. 4) Low Viscocity<br />This property enable water to act as a lubricant.<br />Water is the major component of plasma, mucus and other lubricating fluids.<br />Lubrication is necessary when the internal organs come in contact and slide over one another.<br />It enables blood to function well as an efficient medium of transport for gases and nutrients throughout the body.<br />
  8. 8. 5) High Cohesion and Adhesion of Water<br />The polar nature of water and the formation hydrogen bonds contribute to cohesion in water.<br />Cohesion is the force that attracts water molecules together.<br />The surface tension on the surface of water is the product of the cohesive forces generated by hydrogen bonding between adjacent water molecules and to the molecules below them.<br />Adhesion is referred to as the force of attraction between unlike molecules.<br />
  9. 9. Water is adhesive to any substance with which it can form hydrogen bonds.<br />Both cohesion and adhesive forces are responsible for capillary action. It enable water molecules to rise in fine capillary tubes.<br />With capillary action, minerals dissolved in water are taken up by the roots and are transported up the stem to the leaves.<br />
  10. 10. 6) Lower density in solid state<br />The movement of the molecules slows down and they crowd closer to one another as the temperature of water decreases. <br />As the temperature of water approaches 0°C, the molecules form more hydrogen bonds with each other. They lose kinetic energy.<br />At 0°C or below, water freezes and changes into a solid state. In this state, each molecule is hydrogen bonded firmly to four other water molecules.<br />
  11. 11. PROPERTIES OF WATER AND ITS ROLE<br />
  12. 12. THANK<br />YOU<br />

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