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Chem220 - Organic Chemistry

Chapter 3: Acids and Bases: Curved Arrow Notations

Solution Set

Due: Monday, September 26, 2011

Josiah Willard Gibbs

(1839-1903)

J. W. Gibbs - b. New Haven, CT. Awarded 1st US PhD in the sciences (Yale, SSS, 1863). Developed the concept of free energy and the chemical potential. Gibbs spent his entire career at Yale.

G. N. Lewis - b. Weymouth, MA., Professor UCBerkeley. Developed concept of the covalent bond, dot structures and "Lewis" acids and bases.

Gilbert Newton Lewis

(1875-1946)

1. With the aid of the pK_a table, determine the K_eq for each of the following reactions. Place an equilibrium arrow between the second and third structures that reflects the value of K_eq, i.e., Explain your results.

2. Determine the Gibbs free energy at 25 ^oC of the reaction NH₂^- + H⁺ -------> NH₃. Recall -ΔG^o = RT ln K_eq (-ΔG^o = 2.3RT log K_eq), where R = 1.98 cal/mole-^oK. The pK_a table will be of help.