acids/bases lesson 14 buffers. buffer solutions buffer solutions are equilibrium systems, which...

16

Acids/Bases Lesson 14 Buffers

Upload: lisa-mccarthy

Post on 18-Jan-2016

219 views

Category:

Documents

0 download

Report

Download

Tags:

Embed Size (px):

TRANSCRIPT

Page 1: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Acids/BasesLesson 14

Buffers

Page 2: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Buffer Solutions

Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of acids or bases are added.

How can you prepare a buffer?

You need a high concentration of weak acid or a weak base, and add to it its conjugate acid or its conjugate base also in high concentrations. This combination is known as a BUFFER.

Page 3: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Buffer Solutions

Acid Buffer Recipe

Weak Acid + Salt (conjugate base) HF NaF

*Na+ is a spectator

Buffer Equation Same as weak acid

HF ⇋ H+ + F-

Page 4: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

HF ⇋ H+ + F-

[High] [low] [High]

[HF] is high and [H+] is low because HF is a weak acid.

[F-] is high due to adding the salt NaF.

This buffer solution can shift left or right and the [H+] and the pH remains fairly constant.

Page 5: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Note on buffersA solution of CH3COOH by itself cannot act as a buffer because the concentration of CH3COO- would be too small and will not satisfy the conditions of a buffer system.

A buffer requires large amounts of both the acid and its conjugate.

This is why we mix the weak acid or base with its conjugate salt.

Page 6: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Acidic buffer Mix 1.0 mol of acetic acid (CH3COOH ) and 1.0 mol of sodium acetate (NaCH3COO) and dilute to 1.0 L of solution

Page 7: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Base Buffer Recipe

Weak Base + Salt (conjugate acid)

NH3 NH4Cl *Cl- spectator

Buffer Equation Same as weak base

NH3 + H2O ⇋ NH4+ + OH-

[High] [High] [Low]

Page 8: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Fill in the blanks to get buffer solutions.Acid conjugate Base from a salt

HCN NaCN

H2CO3 NaHCO3

H3PO4 NaH2PO4

CH3COOH KCH3COO

NaHCO3Na2CO3

NaH2PO4Na2HPO4

Page 9: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

How buffers work…

The ‘buffering effect’ works due to the fact that the value of the ratio:[conjugate acid] remains fairly constant.

[conjugate base]

* This ratio does not change much when a small amount of either an acid or a base is added to the buffer system. Why ???

The conjugate acid present can react with the added OH to neutralize it, and the conjugate base present can react with the added H3O to neutralize it.

Page 10: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Buffer Animation 1

http://www.chembio.uoguelph.ca/educmat/chm19104/chemtoons/chemtoons5.htm

Page 11: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Buffer Application

1. Pick the two buffer solutions

A. NH4Cl and HCl

B. NaCl and NaOH

C. HCN and NaCN

D. NH4Cl and NH3

Page 12: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

2. Write the equations for the above two buffer solutions. Label the concentrations as high or low.

Page 13: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

3. A few drops of 0.10 M NaOH is added to a buffer solution at pH = 5.00. The new pH could be:

A 4.98

B. 5.02

C. 8.05

D. 2.11

Page 14: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Buffers in biological systems

Page 15: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

Page 16: Acids/Bases Lesson 14 Buffers. Buffer Solutions Buffer solutions are equilibrium systems, which maintain a relatively constant pH when small amounts of

HomeworkRead page 182 and 183 for “Buffers in biological systems”, must know these systems and how they work.

Page 181: #132,133,138,139

Page 183: #143 on buffers…interesting story/question.

PHARMA S A P I E N C E · ... Calculation of standard potential. ... Buffer-Buffer equations and buffer capacity in general. Buffers in pharmaceutical systems, ... buffered isotonic

Buffers, textures, compositing, shaders - sm.luth.se · • Buffers and images •Textures • Compositing and blending • Vertex and buffer shaders

Titrations and Buffers Supplemental Worksheet KEYch302.cm.utexas.edu/worksheets/titrations-buffers-1-KEY...buffer solution and will use the Henderson-Hasselbach equation to calculate

BUFFERS SUROVIEC SPRING 2014 Chapter 16 1. I. Buffer Solutions A. Buffer is a solution that resists a change in pH with the addition of small amounts

UNIT I Some Basic Concepts of Chemistry 9 hrs · Buffer solutions-definition and examples (acetate and ammonia buffers), Henderson – Hesselbalch equation for acidic buffer to be

Buffer solutions

BUFFER SYSTEMS OF BLOOD SERUM. Loaaed and Self-Possessed Serum Buffers. In a previous

The Preparation of Buffers with ZirChrom’s Buffer … Issues in Buffer Preparation for HPLC ... The Preparation of Buffers with ZirChrom’s Buffer Wizard ... Mobile Phase pH Measurement

1 Buffered and Isotonic Solutions. 2 Contents The Buffer Equation Buffer Capacity Buffers in pharmaceutical and Biologic Systems Buffered Isotonic Solutions

BUFFERS AND SOLUTIONS - blossombio.comblossombio.com/pdf/products/CAT_CANDOR.pdf · Washing Buffer “PBS” 10 ... questions. If this is the case for you, ... described in the chapter

Characterizing Wetland Buffers in Washington State · List of Figures and Tables ... • Buffer is a wetland buffer, not a stream buffer • Project was completed 3. Collecting background

Buffers Solutions

Buffer solutions

Biological Buffers - dia-m.ru · PDF fileand have lasting effects on the system under ... buffers meet most of the requirements that biological buffers have to fulfil. Buffer systems

Buffers, Solutions, and Chemicals

Buffer Cache Waits. In This Section 1.latch: cache buffers chains 2.latch: cache buffers lru chain 3.Free Buffer Wait 4.Buffer Busy Wait 5.Write Complete

1 Packet Switches with Output and Shared Buffer. 2 Packet Switches with Output Buffers and Shared Buffer Packet switches with output buffers, or shared

How deep is your buffer – Demystifying buffers and application performance

Maths and Chemistry for Biologists. Chemistry 4 Buffers This section of the course covers – buffer solutions and how they work the Henderson-Hasselbalch

DURACAL pH BUFFERS - Postnova · values of the calibration buffers are correct. But buffer values can change over time and so can your results. A complete range of patented buffer

Nutrol · Nutrol® is a true tank buffer. can acidify and maintain the pH of tank solutions throughout application. • Nutrol® buffers solutions to the pH recommended for NOTE:

Chemistry 102 EXPERIMENT 8 PURPOSEproffenyes.weebly.com/.../9._experiment_8_-_buffers.pdfChemistry 102 EXPERIMENT 8 BUFFERS Fall 2016/ 2 IV. Calculating the pH of Buffer Solutions

GAM531 DPS931 – Week 12 Textures and Samplers. Actor Composition Actor Mesh Vertex Buffer Index Buffer Vertex Format Material Shaders Uniform Buffers

Acids & Bases (Topics To be covered, Chang 15)chem1aa3/note/acids/1aa3-aci… · Buffer Solutions Chang Chap. 16 Recall use of “Buffer zone”, Buffers contain weak acid + conjugate

8 - 1 Buffers Buffers are solutions that undergo a minimal pH change when small quantities of a strong acid or a strong base is added. A buffer can be

Buffers and Acid-Base Titrations - York University€¦ · Buffers and Acid-Base Titrations ... Applications of Buffer Solutions ... C The pH of a buffer solution is readily calculated

Packet Switches with Output Buffers and Shared Buffer

Lecture #17 Concurrencykoopman/lectures/ece348/17... · 2017-12-02 · • Two buffers Buffer A and Buffer B • Phase 1: – Task 1 owns Buffer A Task 2 owns Buffer B – Task 1

Buffers and Water Quality...Buffers and Water Quality A property owner’s guide to manage riparian buffers and protect water resources If you have questions regarding your buffer

Preparation of buffers. Buffers Buffers are the solutions which resist changes in pH when small amounts of acid or alkali is added to them. A buffer is

Buffer Solutions Final

Buffers and Titrations SSS 3 Class 3. Materials 0.5 M Solutions VinegarNaOH HCl ammonia Sodium Acetate Ammonium Chloride water buffer

Buffer Cache Waits. #.2 In This Section 1.latch: cache buffers chains 2.latch: cache buffers lru chain 3.latch: cache buffer handles 4.Free Buffer Wait

Additional Aqueous Equilibria CHAPTER 16. I. Buffers A. Definitions Buffer- solutions that resist changes in pH when acid or base are added to it. - they

INTERNATIONAL 85p THE BIG ONE!....TMS4164 BUS CONTROL GATE ARRAY 74LS2004 FLOPPY DISC CONTROLLER TMS9909 PHASE LOCKED LOOP BUFFERS BUFFERS BUFFER BUFFER TO …