Chem_208_15_07_web - K a = 1.8 x 10-5 ; pK a = 4.74 [ ] [ ]...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Today: Finishing Ch 17.2 (Buffer Solutions) Continuing 16.6-16.7; Skipping 16.8-16.9 PS6 due Fri. March 16
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 17.2: Buffer Solutions • Resists large pH changes upon addition of an acid or base. • Contains: – Weak acid + conjugate base or – Weak base + conjugate acid • One component neutralizes acids; the other neutralizes bases. Unbuffered: 1.00 L of Pure Water: Add 10.0 ml of 2.0M HCl Buffer: 1.00 L of 1.50M Acetic Acid/ 1.20M Sodium Acetate: Add 10.0 ml of 2.0M HCl pH = 1.69 pH = 4.65 pH = 7.00 pH = 4.63
Background image of page 2
3 Henderson-Hasselbalch Equation For a buffer solution containing a weak acid and its conjugate base: Notes: Equation was derived by assuming M - x M. [conjugage base]/[acid] should lie between 0.10 and 10.0 Molarity of each component should exceed K a by factor of 100. 1.50M Acetic Acid / 1.20 M Sodium Acetate:
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: K a = 1.8 x 10-5 ; pK a = 4.74 [ ] [ ] 65 . 4 09 . 74 . 4 5 . 1 1.2 log 4.74 pH 10 = = + = [ ] [ ] HA A log pK pH-10 a + = 4 Preparing Buffers [ ] [ ] HA A log pK pH-10 a + = 5 Buffer solutions consume added acid or base 6 Buffer solutions consume added acid or base 1.50M Acetic Acid/ 1.20 M Sodium Acetate Add 10.0 ml of 2.0M HCl to 1.00 L of buffer What is the final pH? pH =4.63 7 6 Ways to make a buffer 8 Acid-Base Reactions When mixing acid with base, the reaction proceeds in the direction from the stronger to weaker member of a conjugate acid/base pair. What is favored for each of the following? 1. HCl + OH- Cl-+ H 2 O 2. NH 4 + + OH- H 2 O + NH 3 3. HClO 2 + NH 3 ClO 2-+ NH 4 +...
View Full Document

Page1 / 8

Chem_208_15_07_web - K a = 1.8 x 10-5 ; pK a = 4.74 [ ] [ ]...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online