BCH 119S Lecture Notes - Lecture 3: Tris, Buffering Agent, Sodium Lactate
30 Jan 2016
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Because it is such a small concentration it doesn"t change the ph of water. Q: a solution contains 0. 01 mol of lactic acid (pka=3. 86) and 0. 05 mol of sodium lactate per liter. Change in ph when 5 ml of 0. 5 m hcl is added to 1 l of the solution (may neglect small change in volume of the solution) [a-]f = [a-]o [hcl] = 0. 0475m ph=4. 44. Because hcl strong acid is reacting with the base to make ha. Q: tris is a common buffering agent used in biochemistry labs; has a pka of 8. 1. A: tris is deprotonated form [a-], so will accept more protons. Have to add hcl to make basic go down or tris hydrochloride. Buffers yay: what is the ph when tris base is dissolved to a concentration of. [ha]o=0: what concentration of hcl should be added to 1m tris create a buffer w/ph of 7. 5? ph=-log[h+]
