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Titration and Buffers. Buffers Buffers are substances that are able to absorb and release H+ ions keeping the pH in a solution constant. EX: H 3 O + + HCO 3 - g H 2 CO 3 + OH - g H 2 O + HCO 3 -
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Titration and Buffers Buffers • Buffers are substances that are able to absorb and release H+ ions keeping the pH in a solution constant. • EX: H3O+ + HCO3-g H2CO3 + OH-gH2O + HCO3- • The amount of acid/base can be absorbed without changing the pH of a solution is called the buffer capacity.
Chemical indicator • Is a weak acid or base that changes colors at a certain pH • Each indicator has a specific pH range in which it dissociates to yield [H+] or [OH-] ions and change colors
Acid Base Titration • The acid/base titration is a controlled neutralization reaction. The equivalence point (point of neutralization) is the point where the pH is = 7 and is the mid point in the titration curve. • at the equivalence point the amount of [H3O+] = [OH-]
Categories of Acids - Binary Acids • Contains hydrogen and one other ion • Are strong acids • example - HCl, HBr, HI
Oxy Acids • Contains hydrogen, oxygen, and one other element • Can be both strong or weak acids • example - HNO3, H2SO4,H3PO4
Carboxylic Acids • Contain carbon and a carboxyl group (-COOH) • Are organic acids • most are classified as weak • example - HC2H3O2
Categories of Bases • Anions • Contain negatively charged monatomic or polyatomic ions • Can be either strong or weak • example -CaO, Na2CO3 • Amines • Contain an amine group (NH2) • example - NH3(ammonia), CH3NH2(Methylamine)