Lecture 19.5- Buffers PREP

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Lecture 19.5 for PREP Chemistry

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Lecture 19.5- Buffers PREP

  1. 1. A buffer is a solution that resists changes in pH when moderate amounts of acids or bases are added.
  2. 2. Buffer solutions are prepared by mixing a weak acid with its conjugate base or a weak base with its conjugate acid
  3. 3. Buffer solutions are prepared by mixing a weak acid with its conjugate base or a weak base with its conjugate acid Buffers can neutralize both OH– and H+ when one of these ions is added to the buffered solution.
  4. 4. A buffer solution can be prepared by using the weak base ammonia, NH3, and an ammonium salt, such as NH4Cl.
  5. 5. A buffer solution can be prepared by using the weak base ammonia, NH3, and an ammonium salt, such as NH4Cl. • When acid is added, NH3 reacts with H+. NH3 + H+  NH4+
  6. 6. A buffer solution can be prepared by using the weak base ammonia, NH3, and an ammonium salt, such as NH4Cl. • When acid is added, NH3 reacts with H+. NH3 + H+  NH4+ • If a base is added, the NH4+ ion from the – salt reacts with the OH . NH4+ + OH-  NH3 + H2O
  7. 7. Another buffer system contains the weak acid acetic acid, HC2H3O2, and the salt sodium acetate, NaC2H3O2.
  8. 8. Another buffer system contains the weak acid acetic acid, HC2H3O2, and the salt sodium acetate, NaC2H3O2. • If base is added, the weak acid reacts to neutralize the addition. HC2H3O2 + OH-  C2H3O2- + H2O
  9. 9. Another buffer system contains the weak acid acetic acid, HC2H3O2, and the salt sodium acetate, NaC2H3O2. • If base is added, the weak acid reacts to neutralize the addition. HC2H3O2 + OH-  C2H3O2- + H2O • If acid is added, the acetate ion from the NaC2H3O2 will neutralize the added H+. C2H3O2- + H+  HC2H3O2

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