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Chemistry 19.5. Salts in Solution. 19.5. The chemical processes inside a living cell are very sensitive to pH. Human blood is normally maintained at a pH very close to 7.4. You will learn about chemical processes that ensure that the pH of blood is kept near 7.4. 19.5. Salt Hydrolysis.
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Salts in Solution 19.5 • The chemical processes inside a living cell are very sensitive to pH. Human blood is normally maintained at a pH very close to 7.4. You will learn about chemical processes that ensure that the pH of blood is kept near 7.4.
19.5 Salt Hydrolysis • Salt Hydrolysis • When is the solution of a salt acidic or basic?
19.5 Salt Hydrolysis • In general, salts that produce acidic solutions contain positive ions that release protons to water. Salts that produce basic solutions contain negative ions that attract protons from water.
19.5 Salt Hydrolysis • In salt hydrolysis, the cations or anions of a dissociated salt remove hydrogen ions from or donate hydrogen ions to water.
19.5 Salt Hydrolysis
19.5 Salt Hydrolysis
19.5 Salt Hydrolysis • To determine whether a salt solution is acidic or basic, remember the following rules:
19.5 Salt Hydrolysis • Vapors of the strong acid HCl(aq) and the weak base NH3(aq) combine to form the acidic white salt ammonium chloride (NH4Cl).
19.5 Salt Hydrolysis
19.5 Salt Hydrolysis • Universal indicator solution has been added to each of these 0.10M aqueous salt solutions. CH3COONa pH 5.3 NH4Cl pH 5.3 NaCl pH 7
19.5 Buffers • Buffers • What are the components of a buffer?
19.5 Buffers • A buffer is a solution of a weak acid and one of its salts, or a solution of a weak base and one of its salts. • The pH of a buffer remains relatively constant when small amounts of acid or base are added. • The buffer capacity is the amount of acid or base that can be added to a buffer solution before a significant change in pH occurs.
19.5 Buffers • Buffer of Ethanoic Acid and Sodium Ethanoate • Adding H+ produces additional ethanoic acid. • Adding OH- produces additional ethanoate ions. • The pH changes very little.
19.5 Buffers
Buffers • Animation 26 • Discover the chemistry behind buffer action.
19.5 Buffers
for Conceptual Problem 19.2 • Problem Solving 19.39 • Solve Problem 39 with the help of an interactive guided tutorial.
19.5 Section Quiz. • 19.5
19.5 Section Quiz. • 1. Which of the following reactions would most likely yield a basic salt solution? • strong acid + weak base • weak acid + weak base • strong acid + strong base • weak acid + strong base
19.5 Section Quiz. • 2. Choose the correct words for the spaces. A buffer can be a solution of a _________ and its _________. • weak acid, salt • strong acid, salt • weak acid, conjugate base • weak base, conjugate acid
19.5 Section Quiz. • 3. Which of the following equations represents the reaction when a high pH substance is added to a dihydrogen phosphate ion-hydrogen phosphate ion buffer system? • H2PO4¯+ OH¯ HPO42¯ + H2O • HPO42¯+ OH¯ PO43¯ + H2O • H2PO4¯+ H+ H3PO4 • HPO42¯+ H+ H2PO4¯
Concept Map • Concept Map 19 • Create your Concept Map using the computer.
