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Acids and bases: Properties and definition

Learn about the properties and definitions of acids and bases encountered in daily life, their chemical reactions, uses, and effects like acid rain. Explore pH scale, reactions, indicators, and key concepts in a simplistic approach.

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Acids and bases: Properties and definition

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  1. Acids and bases:Properties and definition

  2. We encounter acids in our daily lives hydrochloric acid (HCl) citric acid (C6H8O7) acetic acid (CH3CO2H) http://www.sunnysidecorp.com/images/Muriatic%20Acid.gif http://www.thekitchn.com/thekitchn/good-questions/what-can-i-do-with-datu-puti-filipino-coconut-vinegargoodquestions119557 http://www.filipinoheritage.com/images/food/aug/kalamansi.jpg

  3. We encounter bases in our daily lives sodium hydroxide (NaOH) ammonia (NH3) http://www.ultramega.com.ph/products-search.php?sub_cat_id=34 http://www.pinegloproducts.com/catalog06/productscatalog/864oz/glass_ammoniacleaners/ammonia_lemon.gif

  4. H2O HX H+(aq) + X-(aq) H2O HCl H+(aq) + Cl-(aq) An acid is a substance that produces H+ when dissolved in water H2O CH3CO2H H+(aq) + CH3CO2-(aq) Aqueous (or aq) is a solution wherein water is the solvent The double-headed arrow signifies that the reaction goes forward and reverse Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  5. H2O MOH M+(aq) + OH-(aq) H2O NaOH Na+(aq) + OH-(aq) A base is a substance that produces OH- when dissolved in water H2O NH3 NH4+(aq) + OH-(aq) The double-headed arrow signifies that the reaction goes forward and reverse Brown, T., E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. 8th ed. Phils: Pearson Education Asia Pte. Ltd. Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  6. Acids taste sour aqueous acid conducts electricity Bases taste bitter feel slippery aqueous base conducts electricity Acids and bases have the following properties Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.

  7. copper wire Ions cause aqueous solutions to be good conductors • to light the bulb, electric current must flow between the two wires • ions carry electrical charge from one wire to another, thereby completing the circuit

  8. Acid-base reaction(aka neutralization reaction)

  9. An acid-base reaction is a reaction between an acidand a base to form salt and water acid + base salt + water HCl + NaOH NaCl + H2O CH3CO2H + KOH KCH3CO2 + H2O salt is an ionic compound made of a cation other than H+ and an anion other than OH- or O2- Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.

  10. When vinegar reacts with baking soda, water and carbon dioxide are produced CH3CO2H + NaHCO3 NaCH3CO2 + H2CO3 H2CO3  H2O + CO2

  11. Acid-base indicators

  12. An indicator is a substance that is added to a solution. It turns one color in an acidic medium and turns another color in a basic medium • litmus paper • phenolphthalein Brown, T., E. LeMay, and B. Bursten. 2000. Chemistry: The Central Science. 8th ed. Phils: Pearson Education Asia Pte. Ltd.

  13. Litmus paper contains various organic compounds. It changes color depending on the acidity/basicity of a solution red to blue: base blue to red: acid http://www.britannica.com/EBchecked/topic/343896/litmus http://oldwww.mtlsd.org/senior/science/JPtachcinski/Lab_Proc/Basic%20Science%20Lab%20Techniques_files/litmus.jpe

  14. Phenolphthalein is colorless in acidic and neutral solutions but reddish pink in basic solutions colorless reddish pink Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill. Skoog, D., D. West, and F.J. Holler. 1996. Fundamentals of Analytical Chemistry 7th ed. USA: Saunders College Publishing.

  15. pH

  16. pH is a logarithmic scale that indicates the amount of H+ in solution pH = - log [H+] where [H+] = concentration of H+ in units of molarity = moles H+ / L of solution

  17. An HCl solution has [H+] = 1.00 x 10-6 M. Calculate for the pH of the solution pH = - log [H+] pH = - log [1.00 x 10-6] = 6.00

  18. pH values indicate if a solution is acidic, neutral, or basic • If pH < 7.00, solution is acidic • If pH = 7.00, solution is neutral • If pH > 7.00, solution is basic

  19. Schedule • Feb 29 • deadline for the submission of outline • Mar 7 (4:30-6:00 pm) • LT # 3 • Mar 9-16 • group reports • Mar 21 (11:30-1:30, C-109) • finals

  20. pH of some familiar aqueous solutions Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  21. Acid rain

  22. The effect of industrial society on the environment is especially apparent in the problem of acid rain major substances involved in acid rain Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  23. SO2 is converted to H2SO4 oxidation SO2 SO3 from power plant emissions SO3 + H2O  H2SO4 Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  24. SO2 is converted to H2SO4 SO2 + H2O  H2SO3 from coal H2SO3 + H2O2  H2SO4 + H2O air pollutant Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  25. Nitrogen oxides (NOx) are converted to HNO3 N2 + O2 NOx at night, NOx  N2O5 N2O5 + H2O  HNO3 Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  26. NO is converted to NO2 and HNO3 NO  NO2 + HNO3 from combustion in car engines and electric power plants Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  27. The pH of rain and snow has adversely declined in many parts of the world • Much of the United States • as early as 1984, average rainfall pH = 4.2 • Sweden • rain with pH = 2.7 (about the same as vinegar) has been observed • West Virginia • rain with pH = 1.8 (between lemon juice and stomach acid) has been observed Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill.

  28. Acid rain is harmful to marble buildings and sculptures 1908 1969 Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.

  29. Acid rain is harmful to the ecosystem http://abacus.bates.edu/~ganderso/biology/bio270/clover_leaf_burns_pH2_30d.gif http://www.elmhurst.edu/~chm/vchembook/images2/195trout.gif

  30. Honey, I told you not to leave your bike out in the rain!

  31. stressed desserts it's just a piece of cake!

  32. Antacids

  33. CO2 + H2O H2CO3 H2CO3 H+ + HCO3- It is natural to have HCl in the stomach, but the problem occurs when the amount of HClis too high in the blood plasma, by-product of metabolism Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill.

  34. To temporarily reduce the amount of HCl in the stomach, an antacid may be taken. The HCl and the antacid undergo an acid-base reaction Kremil-S and Maalox contain Al(OH)3 and Mg(OH)2 3HCl +Al(OH)3 AlCl3 + 3H2O 2HCl +Mg(OH)2 MgCl2 + 2H2O Chang, R. 2002. Chemistry 7th ed. Singapore: McGraw-Hill. Silberberg, M. 2010. Principles of General Chemistry. 2nd ed. New York: McGraw-Hill. http://www.unilab.com.ph/hcp/CMS_Files/kremilStablet_productshot1.jpg http://www.maaloxus.com/assets/productImages/regularLiquid.jpg

  35. Acid inhibitors prevent the production of gastric acids by acting on acid-producing cells in the lining of the stomach http://ecx.images-amazon.com/images/I/51pRnsQMWsL._SL160_.jpg

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