Science Form 2 Water And Solution.Ppt New


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Science Form 2 Water And Solution.Ppt New

  2. 2. <ul><li>Water is a ubiquitous chemical substance , composed of hydrogen and oxygen , that is essential for the survival of all known forms of life . </li></ul><ul><li>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 vapor or steam . </li></ul>
  3. 4. The five most commonly considered physical characteristics are temperature, taste, colour, odour and turbidity. <ul><li>Water is a tasteless, odorless liquid at standard temperature and pressure . </li></ul><ul><li>The color of water and ice is, intrinsically, a very light blue hue, although water appears colorless in small quantities. </li></ul><ul><li>Ice also appears colorless, and water vapor is essentially invisible as a gas. </li></ul>
  4. 5. The freezing point of water is 0° Celsius or 32° Fahrenheit.
  5. 6. Water boils at 100 degrees Celsius or 212 degrees Fahrenheit under standard conditions at sea level (at one atmosphere of pressure). The boiling point of water and any other substance depends on the atmospheric pressure, which changes with elevation. At higher altitudes, the pressure is lower, and so water boils at a lower temperature. If the barometric pressure is not at the standard value, the boiling point will be different.
  6. 7. <ul><li>Contaminants in raw water </li></ul><ul><li>The unique ability of water to dissolve, to some extent, virtually every chemical compound and support practically every form of life means that raw water supplies contain many contaminants. The major categories of impurities found in raw water include: </li></ul><ul><li>Suspended particles, including colloids </li></ul><ul><li>Dissolved inorganic salts </li></ul><ul><li>Dissolved organic compounds </li></ul><ul><li>Micro-organisms </li></ul><ul><li>Pyrogens </li></ul><ul><li>Dissolved gases </li></ul>
  7. 8. Electrolysis of water is the decomposition of water (H 2 O) into oxygen (O 2 ) and hydrogen gas (H 2 ) due to an electric current being passed through the water.
  8. 10. solution is a homogeneous mixture composed of two or more substances solute is dissolved in another substance, known as a solvent . solvent is a liquid or gas that dissolves a solid, liquid, or gaseous solute , resulting in a solution .
  9. 11. <ul><li>Concentrated solution </li></ul><ul><li>It refers to a solution in which much of the water has been removed. </li></ul><ul><li>Dilute solution </li></ul><ul><li>to make (a liquid) thinner or weaker by the addition of water or the like. </li></ul>
  10. 12. <ul><li>Saturated solution </li></ul><ul><li>solution in which the maximum amount of solvent has been dissolved. Any more solute added will sit as crystals on the bottom of the container. </li></ul>
  11. 13. ACIDS Taste: Sour. Touch: Like water. Tested with litmus paper: Turn blue litmus red. pH value: From 0 to less than 7. Reaction with metals: Form hydrogen and a salt. Reaction with carbonates: Form a salt, water and carbon dioxide. Reaction with ammonium compounds: No reaction. ALKALIS Taste: Bitter. Touch: Soapy. Tested with litmus paper: Turn red litmus blue. pH value: From above 7 to 14. Reaction with metals: No reaction. Reaction with carbonates: No reaction. Reaction with ammonium compounds: Give off ammonia gas NEUTRAL
  12. 14. <ul><li>a chemical reaction </li></ul><ul><li>(also called a water forming reaction since a water </li></ul><ul><li>molecule is formed during the process) </li></ul><ul><li>in which an acid and a base or alkali (soluble base) </li></ul><ul><li>react to produce salt and water (H 2 O) . </li></ul>NEUTRALISATION
  13. 15. <ul><li>WATER PURIFICATION </li></ul><ul><li>is the process of removing undesirable chemicals, materials, and biological contaminants from raw water. </li></ul><ul><li>The goal is to produce water fit for a specific purpose. Most water is purified for human consumption ( drinking water ) but water purification may also be designed for a variety of other purposes, including to meet the requirements of medical, pharmacology, chemical and industrial applications. </li></ul><ul><li>In general the methods used include </li></ul><ul><li>physical process such as filtration and sedimentation </li></ul><ul><li>biological processes such as slow sand filters or activated sludge </li></ul><ul><li>chemical process such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light . </li></ul>
  14. 17. <ul><li>WATER SUPPLY </li></ul><ul><li>Is the process of self-provision or provision by third parties in the water industry , commonly a public utility , of water resources of various qualities to different users. Irrigation is covered separately. </li></ul>
  15. 18. <ul><li>Here are some ways to save water. </li></ul><ul><li>Install a water meter </li></ul><ul><li>Check your plumbing for leaks, especially leaking toilets and faucets . </li></ul><ul><li>Take shorter showers. </li></ul><ul><li>Catch the cold water that comes out of the faucet, tap, or shower while you are waiting for the hot water. </li></ul><ul><li>turn the faucet/tap off while you are brushing your teeth, shaving, washing your hands, doing dishes, and so on. </li></ul><ul><li>Catch the rain . Use it for watering your plants, lawn or garden. </li></ul>.