Acid/Base Chemistry Part I

1. Acid/Base Chemistry Part I CHEM 2124 – General Chemistry II Alfred State College Professor Bensley

2. Learning Objectives • Define acid and base according to the Arrhenius concept. • Define acid and base according to the Brønsted–Lowry concept. • Define the term conjugate acid-base pair. • Identify acid and base species. • Define amphiprotic species. • Understand the relationship between the strength of an acid and that of its conjugate base.

3. Learning Objectives • Decide whether reactants or products are favored in an acid-base reaction. • Define the ion-product constant for water. • Calculate the concentrations of H3O+ and OH- in solutions of strong acids or bases. • Define pH and calculate the pH from hydronium-ion concentrations. • Calculate the hydronium-ion concentration from pH.

5. Opener

6. Introduction to Acids and Bases A. Arrhenius Definition B. The Brønsted–Lowry Definition

9. A− B Acid/Base Chemistry C. Proton Transfer Reactions gain of H+ H A + + H B+ conjugate acid acid base conjugate base loss of H+

10. Acid/Base Chemistry D. Relating Acid and Base Strength When a covalent acid dissolves in water, the proton transfer that forms H3O+ is called dissociation. A weak acid contains mostly undissociated acid, CH3COOH. A strong acid, HCl, is completely dissociated into H3O+(aq) and Cl−(aq).

11. Acid and Base StrengthRelating Acid and Base Strength A strong base, NaOH, is completely dissociated into Na+(aq) and −OH(aq). A weak base contains mostly undissociated base, NH3.

13. A− A− B B Acid/Base Chemistry E. Acid/Base Equilibrium A Brønsted–Lowry acid–base reaction represents an equilibrium. + H A + H B+ conjugate acid acid base conjugate base H A + + H B+ stronger acid stronger base weaker base weaker acid

14. − H O Acid/Base Chemistry F. Dissocciation of Water loss of H+ + H H O H H O H H O H + + acid base conjugate acid conjugate base gain of H+ Kw =

15. Acid/Base Chemistry F. Calculating pH pH = −log [H3O+]

17. Focus on the Human BodyThe pH of Body Fluids 17