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Explore the chemical processes within cells and the importance of maintaining blood pH at 7.4. Learn about salt hydrolysis and buffer systems in maintaining pH balance. Discover how salts produce acidic or basic solutions.
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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.
