Acids and bases


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Acids and Bases Form 4

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Acids and bases

  1. 1. Chapter 7ACIDS AND BASES<br />
  2. 2. What is acid?<br /><ul><li>a substance that ionizes in water to produce hydrogen ions, H+</li></ul>What is base?<br /><ul><li>a substance that reacts with an acid to </li></ul> form only salt and water<br />What is alkali?<br /><ul><li>Soluble bases that produce OH¯ ions in water</li></li></ul><li>Chemical properties of acid<br /><ul><li> Sour taste
  3. 3. pH less than 7
  4. 4. Corrosive
  5. 5. Conduct electricity
  6. 6. Acid can react with</li></ul> a) bases to produce salts and water<br /> b) metals to produce salts and hydrogen gas<br /> c) carbonates to produce salts , carbon dioxide gas and water<br />
  7. 7. Chemical properties of base<br /><ul><li> Bitter/smooth/soapy
  8. 8. pH more than 7
  9. 9. Corrosive
  10. 10. Conduct electricity
  11. 11. Base can react with</li></ul> a)Acid to produce a salt and water<br /> b)Heated with ammonium salt to produce ammonia gas<br />video <br />
  12. 12. Uses of acids in daily life<br /><ul><li>Sulphuric acid – paints, detegents, polymers, fertilisers
  13. 13. Carbonic acid- make carbonated drinks
  14. 14. Ethanoic acid- vinegar</li></ul>Uses of base in daily life<br /><ul><li>Sodium hydroxide – soaps, detergents, bleaching agents
  15. 15. Magnesium hydroxide – toothpaste
  16. 16. Ammonia- fertilisers</li></li></ul><li>Role of water in the formation of hydrogen ions<br /><ul><li>In the presence of water, an acid will ionize to form the hydrogen ions, H+
  17. 17. So, water is essential for the formation of hydrogen ions that cause acidity</li></li></ul><li>Role of water in the formation of hydroxide ions<br /><ul><li>In the presence of water, alkali will dissociate to form hydroxide ions, OH¯
  18. 18. Hence, water is essential for the formation of hydroxide ions that cause alkalinity</li></li></ul><li>pH scale<br />
  19. 19. <ul><li>A set of numbers used to show the degree of acidity and alkalinity of a solution
  20. 20. pH values of less than 7 indicates an acidic solution
  21. 21. pH values of more than 7 indicates an alkaline solution
  22. 22. pH values of 7 indicates a neutral solution</li></li></ul><li>pH values<br />Higher pH value <br /><ul><li>more alkaline
  23. 23. higher concentration of hydroxide ion</li></ul>Lower pH value <br /><ul><li>more acidic
  24. 24. higher concentration of hydrogen ion</li></ul>When acids meets base<br />
  25. 25. pH is actually a measurement of the concentration of hydrogen, H+ in a solution<br />The higher the concentration of the H+<br /> ions, the lower the pH value, and more acidic the solution is<br />The higher the concentration of the OH¯ ions, the higher the pH value and the more alkaline solution the solution is.<br />
  26. 26. Acid<br /><ul><li>Strong acidis an acid that dissociate (ionize ) completely in water to form hydrogen ion,H+ of high concentration
  27. 27. Weak acidis an acid that dissociate (ionize ) partially in water to produce hydrogen ions,H+ of low concentration.</li></li></ul><li>Mineral acids such as hydrochloric acid, nitric acid, and sulphuric acid are strong acids<br />Weak acids-ethanoic acid, methanoic acid, citric acid, tartaric acid<br />
  28. 28. Alkali<br /><ul><li>Strong alkaliis produce when a base dissociates completely in water to produce hydroxide ions, OH- of high concentration
  29. 29. Weak alkaliis produced when a base dissociates partially to produce hydroxide ions, OH- of low concentration.</li></li></ul><li>Strong alkali- sodium hydroxide, potassium hydroxide<br />Weak alkali- ammonia solution<br />
  30. 30. EDITED BY :<br />NoorLailibintiMohamad Elias<br />D20091034948<br />ISMP KIMIA 2009/2010<br />Thank you<br />