EXPT 11. pk a of ph Indicators

Size: px
Start display at page:

Download "EXPT 11. pk a of ph Indicators"

Transcription

1 EXPT 11. pk a of ph Indicators [Key Contents] - acid dissociation constant, pk a - buffer, Henderson-Hasselbalch equation - spectrophotometry, Beer's law - ph indicator [References] Principles of Modern Chemistry, 6th Ed. (Oxtoby et al.) Ch 15. Acid-Base Equilibria Chemistry for Life, Chemistry for Better Life (Kim et al.) Ch 9. Equilibrium Reactions [Goal] - to understand basic principles of acid dissociation equilibrium - to learn to use Henderson-Hasselbalch equation in acid dissociation equilibrium - to learn basic principles of spectrophotometry [Background] A typical ph indicator (HInd) is a weak acid that undergoes acid dissociation in solution with an accompanying color change. HInd Ind - + H + The color of the solution is determined by the concentration ratio between HInd and Ind -. The concentration of HInd and Ind - can be measured using Beer's law. A = εbc ε: molar extinction coefficient, b: path length, A: absorbance

2 You will first obtain absorption spectrum of the indicator at acidic and basic ph and select a wavelength where HInd absorbs strongly and Ind - absorbs little. Then you will measure the decreased absorbtion at this wavelength as the ph of the indicator solution is increased gradually using buffers of different ph. The decrease in absorbance corresponds to the concentration of Ind -. The pk a of HInd is the ph at which [HInd] and [Ind-] are the same. You can determine pk a of the indicator by plotting log([ind-]/[hind]) against ph. [Apparatus and Chemicals] spectrophotometer, cuvette, test tubes, 10 ml pipet, Pasteur pipet 0.01 mm bromophnol blue (BPB) solution, 0.02 mm phenolphthalein solution 0.1 N HCl solution, 0.1 N NaOH solution, 10 mm buffer solutions (ph 3.4, 3.7, 4.0, 4.3, 4.6, 7.0, 8.5, 9.0, 9.5, 9.8)

3 [Procedure] Expt 1. pka of Bromophenol Blue 1) In separate test tubes, prepare following mixtures. mixture 1 : 2.0 ml 0.05 mm BPB soln ml 0.1 N HCl soln mixture 2 : 2.0 ml 0.05 mm BPB soln ml ph 3.4 buffer mixture 3 : 2.0 ml 0.05 mm BPB soln ml ph 3.7 buffer mixture 4 : 2.0 ml 0.05 mm BPB soln ml ph 4.0 buffer mixture 5 : 2.0 ml 0.05 mm BPB soln ml ph 4.3 buffer mixture 6 : 2.0 ml 0.05 mm BPB soln ml ph 4.6 buffer mixture 7 : 2.0 ml 0.05 mm BPB soln ml ph 7.0 buffer 2) Using a spectrophotometer, obtain absorption spectrum from mixture 1 and 7. Read absorbance between nm at 25 nm intervals. Read absorbance at 5 nm intervals at the absorption peak. Put the solution back to the test tube. Determine wavelength for maximum absorption (λ max) for HInd from mixture 1. Determine λ max for Ind - from mixture 7. 3) From mixture 2~6, read absorbance at both λ max. 4) Visually, estimate the ph where the color of the solution is the mixed color of mixture 1 and 7 in equal volume. 5) Test of Beer's Law : In a test tube, mix 2 ml of mixture 1 with 2 ml of 0.1 N HCl solution to make mm BPB solution and read absorption at both λ max. Next, mix 2 ml of the mm BPB solution with 2 ml of 0.1 N HCl solution to make mm BPB solution and read absorption at both λ max. Finally, mix 2 ml of the mm BPB solution with 2 ml of the mm BPB solution to make mm BPB solution and read absorption at both λ max.

4 HO Expt 2. pka of Phenolphthalein OH 1) In separate test tubes, prepare following mixtures. O O phenolphthalein mixture 1 : 2.0 ml 0.02 mm phenolphthalein ml ph 7.0 buffer mixture 2 : 2.0 ml 0.02 mm phenolphthalein ml ph 8.5 buffer mixture 3 : 2.0 ml 0.02 mm phenolphthalein ml ph 9.0 buffer mixture 4 : 2.0 ml 0.02 mm phenolphthalein ml ph 9.5 buffer mixture 5 : 2.0 ml 0.02 mm phenolphthalein ml ph 9.8 buffer mixture 6 : 2.0 ml 0.02 mm phenolphthalein ml 0.1 N NaOH 2) Using a spectrophotometer, obtain absorption spectrum from mixture 1 and 6. Read absorbance between nm at 25 nm intervals. Read absorbance at 5 nm intervals at the absorption peak. Put the solution back to the test tube. Determine λ max for Ind - from mixture 6. 3) From mixture 1~5, read absorbance at λ max. 4) Visually, estimate the ph where the color of the solution is the mixed color of mixture 1 and 6 in equal volume. 5) Test of Beer's Law : In a test tube, mix 1.5 ml of mixture 6 with 1.5 ml of 0.1 N NaOH solution to make 0.01 mm phenolphthalein solution

5 and read absorption at λ max. Next, mix 1.5 ml of the 0.01 mm phenolphthalein solution with 1.5 ml of ph 7.0 buffer solution to make mm phenolphthalein solution and read absorption at both λ max. Finally, mix 1.5 ml of the 0.01 mm phenolphthalein solution with 1.5 ml of the 0.02 mm phenolphthalein solution to make mm phenolphthalein solution and read absorption at both λ max. [Data Analysis] Expt 1. pka of Bromophenol Blue 1) Draw an absorption spectrum for mixture 1 and determine λ max and ε at λ max. Calculate [HInd] from absorbance at λ max. 2) Plot [HInd] and [Ind - ] againt the molar concentration of BPB. Is the Beer's law valid? 3) For mixture 2~6, calculate [HInd] at different ph's from absorbance at λ max. 4) Calculate [Ind - ] as difference between [HInd] for mixture 1 and [HInd] at different ph's. 5) Plot log[ind - ]/[HInd] againt ph and determine pk a of BPB as the ph where log[ind - ]/[HInd] is zero. 6) Draw an absorption spectrum for mixture 7 and determine λ max and ε at λ max. Calculate [Ind - ] from absorbance at λ max. 7) For mixture 2~6, calculate [Ind - ] at different ph's from absorbance at λ max. 8) Calculate [HInd] as difference between [Ind - ] for mixture 7 and

6 [Ind - ] at different ph's. 9) Plot log[ind - ]/[HInd] againt ph and determine pk a of BPB as the ph where log[ind - ]/[HInd] is zero. 10) Compare pk a values obtained by both methods. How good is the agreement? Compare the average of the two pk a values with the literature value of K a, 1.5 x Expt 2. pka of Phenolphthalein 1) Draw an absorption spectrum for mixture 6 and determine λ max and ε at λ max. Calculate [Ind - ] from absorbance at λ max. 2) Plot [Ind - ] againt the molar concentration of BPB. Is the Beer's law valid? 3) Plot log[ind - ]/[HInd] againt ph and determine pk a of phenolphthalein as the ph where log[ind - ]/[HInd] is zero. 4) Compare pk a values obtained with the literature value of 9.3. Discuss why phenolphthalein is a good indicator for titrating strong acid with strong base.

7 [Additional Material] Phenol Red and Phenolphthalein ph 5.5 phenol red phenolphthalein 12

AIM To verify Beer - Lambert s law and to determine the dissociation constant (Ka) of methyl red, Spectrophotometrically.

AIM To verify Beer - Lambert s law and to determine the dissociation constant (Ka) of methyl red, Spectrophotometrically. C 141(Expt. No. ) NAME : ROLL No. : SIGNATURE : BATCH : DATE : VERIFICATION OF BEER - LAMBERT S LAW & DETERMINATION OF DISSOCIATION CONSTANT (Ka) OF METHYLRED, SPECTROPHOTOMETRICALLY AIM To verify Beer

More information

Chapter 17 Answers. Practice Examples [H3O ] 0.018M, 1a. HF = M. 1b. 30 drops. 2a.

Chapter 17 Answers. Practice Examples [H3O ] 0.018M, 1a. HF = M. 1b. 30 drops. 2a. Chapter 17 Answers Practice Examples 1a. + [HO ] 0.018M, 1b. 0 drops [HF] = 0.8 M. [H O + ] = 0.10 M, HF = 0.97 M. a. + HO 1.10 M, CHO = 0.150 M. b. 15g NaCHO a. The hydronium ion and the acetate ion react

More information

Titration of a Weak Acid with a Strong Base

Titration of a Weak Acid with a Strong Base Titration of a Weak Acid with a Strong Base Weak Acid w/ Strong Base Overall: INITIAL ph: Weak acids do not fully dissociate we need to do an ICE table to determine initial ph. We expect it to be weakly

More information

CHAPTER 7 Acid Base Equilibria

CHAPTER 7 Acid Base Equilibria 1 CHAPTER 7 Acid Base Equilibria Learning Objectives Acid base theories Acid base equilibria in water Weak acids and bases Salts of weak acids and bases Buffers Logarithmic concentration diagrams 2 ACID

More information

CHEM 254 EXPERIMENT 9. Chemical Equilibrium-Colorimetric determination of equilibrium constant of a weak acid

CHEM 254 EXPERIMENT 9. Chemical Equilibrium-Colorimetric determination of equilibrium constant of a weak acid CHEM 254 EXPERIMENT 9 Chemical Equilibrium-Colorimetric determination of equilibrium constant of a weak acid For a weak acid that can only partly dissociate the equilibrium constant is related to activities

More information

16.3 Weak Acids Weak Bases Titration

16.3 Weak Acids Weak Bases Titration 16.3 Weak Acids Weak Bases Titration Titration of Weak Acid with Strong Base Titration of Base Acid with Strong Acid Dr. Fred Omega Garces Chemistry 201 Miramar College 1 Weak Acids Weak Bases Titration

More information

Lecture 12. Acid/base reactions. Equilibria in aqueous solutions.

Lecture 12. Acid/base reactions. Equilibria in aqueous solutions. Lecture 12 Acid/base reactions. Equilibria in aqueous solutions. Titrations Kotz 7 th ed. Section 18.3, pp.821-832. In a titration a solution of accurately known concentration is added gradually added

More information

We need to find the new concentrations of the species in this buffer system. Remember that we also DILUTED the solution by adding 5.0 ml of the HCl.

We need to find the new concentrations of the species in this buffer system. Remember that we also DILUTED the solution by adding 5.0 ml of the HCl. 164 Take 100. ml of the previous buffer (0.05 M tris / 0.075 M tris-hcl), and add 5.0 ml of.10 M HCl. What is the ph of the mixture? The HCl reacts with the tris base, converting it to tris-hcl We need

More information

Kotz 7 th ed. Section 18.3, pp

Kotz 7 th ed. Section 18.3, pp Lecture 15 Acid/base reactions. Equilibria in aqueous solutions. Titrations Kotz 7 th ed. Section 18.3, pp.821-832. In a titration a solution of accurately known concentration is added gradually added

More information

Chapter 15. Acid-Base Equilibria

Chapter 15. Acid-Base Equilibria Chapter 15 Acid-Base Equilibria The Common Ion Effect The common-ion effect is the shift in an ionic equilibrium caused by the addition of a solute that provides an ion already involved in the equilibrium

More information

Chemistry 132 NT. Acid-Base Equilibria

Chemistry 132 NT. Acid-Base Equilibria Chemistry 132 NT Instead of having answers on a math test, they should just call them impressions, and if you got a different impression, so what, can t we all be brothers? Jack Handey 1 2 Chem 132 NT

More information

ACID-BASE EQUILIBRIA. Chapter 14 Big Idea Six

ACID-BASE EQUILIBRIA. Chapter 14 Big Idea Six ACID-BASE EQUILIBRIA Chapter 14 Big Idea Six Acid-Base Equilibria Common Ion Effect in Acids and Bases Buffer SoluDons for Controlling ph Buffer Capacity ph-titradon Curves Acid-Base TitraDon Indicators

More information

Acid Base Equilibria

Acid Base Equilibria Acid Base Equilibria Acid Ionization, also known as acid dissociation, is the process in where an acid reacts with water to produce a hydrogen ion and the conjugate base ion. HC 2 H 3 O 2(aq) H + (aq)

More information

Chapter 15. Acid-Base Equilibria

Chapter 15. Acid-Base Equilibria Chapter 15 Acid-Base Equilibria Section 15.1 Solutions of Acids or Bases Containing a Common Ion Common Ion Effect Shift in equilibrium position that occurs because of the addition of an ion already involved

More information

Experiment 32C APPLICATIONS OF ACID-BASE EQUILIBRIA

Experiment 32C APPLICATIONS OF ACID-BASE EQUILIBRIA Experiment 32C APPLICATIONS OF ACID-BASE EQUILIBRIA FV 23Feb18 MATERIALS: 50 ml buret (2), 25 ml graduated cylinder (2), 50 ml beaker (2), 150 ml beaker (2), small plastic vials (6), stirring rods (2),

More information

Buffer Effectiveness, Titrations & ph curves. Section

Buffer Effectiveness, Titrations & ph curves. Section Buffer Effectiveness, Titrations & ph curves Section 16.3-16.4 Buffer effectiveness Buffer effectiveness refers to the ability of a buffer to resist ph change Effective buffers only neutralize small to

More information

Chapter 17: Additional Aspects of Aqueous equilibria. Common-ion effect

Chapter 17: Additional Aspects of Aqueous equilibria. Common-ion effect Chapter 17: Additional Aspects of Aqueous equilibria Learning goals and key skills: Describe the common ion effect. Explain how a buffer functions. Calculate the ph of a buffer solution. Calculate the

More information

Equilibri acido-base ed equilibri di solubilità. Capitolo 16

Equilibri acido-base ed equilibri di solubilità. Capitolo 16 Equilibri acido-base ed equilibri di solubilità Capitolo 16 The common ion effect is the shift in equilibrium caused by the addition of a compound having an ion in common with the dissolved substance.

More information

CHEMISTRY 31 FINAL EXAM - SOLUTIONS Dec. 10, points total

CHEMISTRY 31 FINAL EXAM - SOLUTIONS Dec. 10, points total CHEMISTRY 31 FINAL EXAM - SOLUTIONS Dec. 10, 2012 150 points total A. Multiple Choice and Short answer Section. Multiple Choice Answers in bold 1. A student calculates their unknown soda ash % NaCO 3 as

More information

Spectrometric Determination of the Acid Dissociation Constant of an Acid-base Indicator

Spectrometric Determination of the Acid Dissociation Constant of an Acid-base Indicator Spectrometric Determination of the Acid Dissociation Constant of an Acid-base Indicator Learning Goals 1. Gain appreciation of the dynamics of perturbing a chemical equilibrium 2. Gain an understanding

More information

Acid-Base Equilibria and Solubility Equilibria Chapter 17

Acid-Base Equilibria and Solubility Equilibria Chapter 17 PowerPoint Lecture Presentation by J. David Robertson University of Missouri Acid-Base Equilibria and Solubility Equilibria Chapter 17 The common ion effect is the shift in equilibrium caused by the addition

More information

Analyte: The substance whose concentration is not known in a titration. Usually the analyte is in the flask or beaker beneath the burette.

Analyte: The substance whose concentration is not known in a titration. Usually the analyte is in the flask or beaker beneath the burette. Key Worksheet 15 Acids & Base Equilibria: Acid Base Titrations Objectives To be able to calculate the ph, poh, and concentrations of all species present at any point of an acid base titration. Vocabulary

More information

Spectrophotometric Determination of pka of Phenol Red

Spectrophotometric Determination of pka of Phenol Red Spectrophotometric Determination of pka of Phenol Red This experiment uses instrumentation to accomplish quantitative analysis. You will get far more experience in this during CH427 if you are a Chemistry

More information

Lecture #11-Buffers and Titrations The Common Ion Effect

Lecture #11-Buffers and Titrations The Common Ion Effect Lecture #11-Buffers and Titrations The Common Ion Effect The Common Ion Effect Shift in position of an equilibrium caused by the addition of an ion taking part in the reaction HA(aq) + H2O(l) A - (aq)

More information

Preparation of different buffer solutions

Preparation of different buffer solutions Preparation of different buffer solutions 1 - Buffers: - All biochemical reactions occur under strict conditions of the concentration of hydrogen ion. - Biological life cannot withstand large changes in

More information

EXPERIMENT 14. ACID DISSOCIATION CONSTANT OF METHYL RED 1

EXPERIMENT 14. ACID DISSOCIATION CONSTANT OF METHYL RED 1 EXPERIMET 14. ACID DISSOCIATIO COSTAT OF METHYL RED 1 The acid dissociation constant, Ka, of a dye is determined using spectrophotometry. Introduction In aqueous solution, methyl red is a zwitterion and

More information

A 95 g/mol B 102 /mol C 117 g/mol D 126 g/mol E 152 g/mol

A 95 g/mol B 102 /mol C 117 g/mol D 126 g/mol E 152 g/mol Titrations In a titration a solution of accurately known concentration is added gradually added to another solution of unknown concentration until the chemical reaction between the two solutions is complete.

More information

Chapter 17 Additional Aspects of Aqueous Equilibria (Part A)

Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) What is a dominant equilibrium? How do we define major species? Reactions between acids and bases 1. Strong Acids + Strong Base The reaction

More information

Introduction to biochemical practicals. Vladimíra Kvasnicová

Introduction to biochemical practicals. Vladimíra Kvasnicová Introduction to biochemical practicals Vladimíra Kvasnicová arrangement of practicals laboratory safety regulations laboratory equipment dealing with automatic pipette instructions: http://vyuka.lf3.cuni.cz/

More information

First week Experiment No.1 / /2013. Spectrophotometry. 1. Determination of copper via ammine complex formation using standard series method

First week Experiment No.1 / /2013. Spectrophotometry. 1. Determination of copper via ammine complex formation using standard series method First week Experiment No.1 / /2013 Spectrophotometry 1. Determination of copper via ammine complex formation using standard series method Principal In the standard series method the teat and standard solution

More information

Acid-Base Titration Solution Key

Acid-Base Titration Solution Key Key CH3NH2(aq) H2O(l) CH3NH3 (aq) OH - (aq) Kb = 4.38 x 10-4 In aqueous solution of methylamine at 25 C, the hydroxide ion concentration is 1.50 x 10-3 M. In answering the following, assume that temperature

More information

CHEM 1471 Kinetics of Phenolphthalein Decolorization Fall 2010 (Buckley) Lab Under Development

CHEM 1471 Kinetics of Phenolphthalein Decolorization Fall 2010 (Buckley) Lab Under Development CHEM 1471 Kinetics of Phenolphthalein Decolorization Fall 2010 (Buckley) Lab Under Development Objective: Use spectrophotometry to determine the order of the kinetics of decolorization of phenolphthalein

More information

Pharmaceutical Analytical Chemistry (PHCM223-SS16) Lecture 5 ACID- BASE EQUILIBRIUM-V ph indicators

Pharmaceutical Analytical Chemistry (PHCM223-SS16) Lecture 5 ACID- BASE EQUILIBRIUM-V ph indicators Pharmaceutical Analytical Chemistry (PHCM223-SS16) Lecture 5 ACID- BASE EQUILIBRIUM-V ph indicators Dr. Rasha Hanafi PHCM223,SS16 Lecture 5, Dr. Rasha Hanafi 1 LEARNING OUTCOMES By the end of this session

More information

Chapter 17. Additional Aspects of Aqueous Equilibria. Lecture Presentation. John D. Bookstaver St. Charles Community College Cottleville, MO

Chapter 17. Additional Aspects of Aqueous Equilibria. Lecture Presentation. John D. Bookstaver St. Charles Community College Cottleville, MO Lecture Presentation Chapter 17 Additional Aspects of John D. Bookstaver St. Charles Community College Cottleville, MO The Common-Ion Effect Consider a solution of acetic acid: CH 3 COOH(aq) + H 2 O(l)

More information

Lab #12: Determination of a Chemical Equilibrium Constant

Lab #12: Determination of a Chemical Equilibrium Constant Lab #12: Determination of a Chemical Equilibrium Constant Objectives: 1. Determine the equilibrium constant of the formation of the thiocyanatoiron (III) ions. 2. Understand the application of using a

More information

Table of Contents. Purpose... 2 Background... 2 Prelab Questions... 3 Procedure:... 3 Calculations:... 4

Table of Contents. Purpose... 2 Background... 2 Prelab Questions... 3 Procedure:... 3 Calculations:... 4 Table of Contents Purpose... 2 Background... 2 Prelab Questions... 3 Procedure:... 3 Calculations:... 4 CHM 212 Experiment 4 Determination of the Ka of Potassium Hydrogen Phthalate (KHP) Using a Gran Plot

More information

Practical Note BIOCHEMICAL CALCULATIONS (BCH 312)

Practical Note BIOCHEMICAL CALCULATIONS (BCH 312) I II 2011 King Saud University College of Science kingdom of Saudi Arabia Ministry of Higher Education king Saud University College of Science Practical Note BIOCHEMICAL CALCULATIONS (BCH 312) Prepared

More information

Acid-Base Equilibria. And the beat goes on Buffer solutions Titrations

Acid-Base Equilibria. And the beat goes on Buffer solutions Titrations Acid-Base Equilibria And the beat goes on Buffer solutions Titrations 1 Common Ion Effect The shift in equilibrium due to addition of a compound having an ion in common with the dissolved substance. 2

More information

Consider a normal weak acid equilibrium: Which direction will the reaction shift if more A is added? What happens to the % ionization of HA?

Consider a normal weak acid equilibrium: Which direction will the reaction shift if more A is added? What happens to the % ionization of HA? ch16blank Page 1 Chapter 16: Aqueous ionic equilibrium Topics in this chapter: 1. Buffers 2. Titrations and ph curves 3. Solubility equilibria Buffersresist changes to the ph of a solution. Consider a

More information

EXAM 2 CHEMISTRY 224 March 1, Use a #2 pencil to code all information on the answer sheet.

EXAM 2 CHEMISTRY 224 March 1, Use a #2 pencil to code all information on the answer sheet. 1. Read the following instructions carefully EXAM CHEMISTRY March 1, 01. Write your name and Purdue ID number on the answer sheet 3. Write your Graduate Instructor s name on the line for Instructor on

More information

Page 1 of 7 Chem 201 Lecture11 Summer 07. Admin: recall all Test #1 s Please turn in Test 1 for regrading. Last time:

Page 1 of 7 Chem 201 Lecture11 Summer 07. Admin: recall all Test #1 s Please turn in Test 1 for regrading. Last time: Page 1 of 7 Chem 201 Lecture11 Summer 07 Admin: recall all Test #1 s Please turn in Test 1 for regrading Last time: 1. calibration methods 2. mixtures 3. Acid Base reactions AcidBase Calculations: ACIDS

More information

I. Acids & Bases. A. General ideas:

I. Acids & Bases. A. General ideas: Acid-Base Equilibria 1. Application of equilibrium concepts. 2. Not much else new in the way of theory is presented. 3. Specific focus on aqueous (H O is 2 solvent) systems. 4. Assume we are at equilibrium

More information

So, What Does it Indicate?

So, What Does it Indicate? So, What Does it Indicate? Introduction Phenolphthalein is a common indicator you may have used in a previous science course, such as Chemistry 184. In solutions with a ph of less then 8.3, this compound

More information

Example 15.1 Identifying Brønsted Lowry Acids and Bases and Their Conjugates

Example 15.1 Identifying Brønsted Lowry Acids and Bases and Their Conjugates Example 15.1 Identifying Brønsted Lowry Acids and Bases and Their Conjugates For Practice 15.1 In each reaction, identify the Brønsted Lowry acid, the Brønsted Lowry base, the conjugate acid, and the conjugate

More information

Department of Chemistry University of Texas at Austin

Department of Chemistry University of Texas at Austin Polyprotic and Special Cases Calculations Supplemental Worksheet KEY For the following polyprotic acid questions: Citric acid (H3C6H5O6) Ka1 = 8.4 x 10 4 Ka2 = 1.8 x 10 5 Ka3 = 4.0 x 10 6 Oxalic acid (H2C2O4)

More information

Chapter 17 Additional Aspects of Aqueous Equilibria (Part A)

Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) Chapter 17 Additional Aspects of Aqueous Equilibria (Part A) Often, there are many equilibria going on in an aqueous solution. So, we must determine the dominant equilibrium (i.e. the equilibrium reaction

More information

KEY. Practice Problems: Applications of Aqueous Equilibria

KEY. Practice Problems: Applications of Aqueous Equilibria Practice Problems: Applications of Aqueous Equilibria KEY CHEM 1B 1. Ammonia (NH3) is a weak base with a Kb = 1.8 x 1 5. a) Write the balanced chemical equation for the reaction of ammonia with water.

More information

Acid-Base Equilibria and Solubility Equilibria

Acid-Base Equilibria and Solubility Equilibria ACIDS-BASES COMMON ION EFFECT SOLUBILITY OF SALTS Acid-Base Equilibria and Solubility Equilibria Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 2 The common

More information

Applications of Aqueous Equilibria. Chapter 18

Applications of Aqueous Equilibria. Chapter 18 Applications of Aqueous Equilibria Chapter 18 What we learn from Chap 18 This chapter is the third in the three-chapter sequence about equilibrium, this one building upon the core principles raised in

More information

Operational Skills. Operational Skills. The Common Ion Effect. A Problem To Consider. A Problem To Consider APPLICATIONS OF AQUEOUS EQUILIBRIA

Operational Skills. Operational Skills. The Common Ion Effect. A Problem To Consider. A Problem To Consider APPLICATIONS OF AQUEOUS EQUILIBRIA APPLICATIONS OF AQUEOUS EQUILIBRIA Operational Skills Calculating the common-ion effect on acid ionization Calculating the ph of a buffer from given volumes of solution Calculating the ph of a solution

More information

Chem Chapter 18: Sect 1-3 Common Ion Effect; Buffers ; Acid-Base Titrations Sect 4-5 Ionic solubility Sect 6-7 Complex Formation

Chem Chapter 18: Sect 1-3 Common Ion Effect; Buffers ; Acid-Base Titrations Sect 4-5 Ionic solubility Sect 6-7 Complex Formation Chem 106 3--011 Chapter 18: Sect 1-3 Common Ion Effect; Buffers ; Acid-Base Titrations Sect 4-5 Ionic solubility Sect 6-7 Complex Formation 3//011 1 The net ionic equation for the reaction of KOH(aq) and

More information

Acid-Base Equilibria (Chapter 10.) Problems: 2,3,6,13,16,18,21,30,31,33

Acid-Base Equilibria (Chapter 10.) Problems: 2,3,6,13,16,18,21,30,31,33 Acid-Base Equilibria (Chapter 10.) Problems: 2,3,6,13,16,18,21,30,31,33 Review acid-base theory and titrations. For all titrations, at the equivalence point, the two reactants have completely reacted with

More information

Acids, Bases and the Common Ion Effect. More quantitative. Continued [F - ] = M. Consider the following acid equilibrium of a weak acid:

Acids, Bases and the Common Ion Effect. More quantitative. Continued [F - ] = M. Consider the following acid equilibrium of a weak acid: Acids, Bases and the Common Ion Effect Consider the following acid equilibrium of a weak acid: HF + H O H 3 O + + F - K a = [H 3 O + ][F - ] [HF] By LeChatelier s principle, we predict the HF dissociation

More information

mol of added base 36. Equal moles of which of the following chemicals could be used to make a basic (1 mark)

mol of added base 36. Equal moles of which of the following chemicals could be used to make a basic (1 mark) 59. 34. Consider the following titration curve: 14 13 Consider the following titration curve: 14 1 13 11 14 1 1 13 119 1 18 ph 119 7 18 6 ph 97 5 86 4 ph 75 3 64 53 1 4 31 mol of added base Select a suitable

More information

Ch. 17 Applications of Aqueous Equilibria: Buffers and Titrations

Ch. 17 Applications of Aqueous Equilibria: Buffers and Titrations Ch. 17 Applications of Aqueous Equilibria: Buffers and Titrations Sec 1 The Common-Ion Effect: The dissociation of a weak electrolyte decreases when a strong electrolyte that has an ion in common with

More information

Chemistry 265 December Exam 2011 Smith-Palmer

Chemistry 265 December Exam 2011 Smith-Palmer 1 Chemistry 265 December Exam 2011 Smith-Palmer NAME: [1] 1. Define an anode [1] Define a cathode [2] What is the E o for the following reaction: Ag + + Cu Ag (s) + Cu 2+ Ag + + e - Ag (s) E o = 0.799

More information

Grade A buffer: is a solution that resists changes in its ph upon small additions of acid or base.sq1

Grade A buffer: is a solution that resists changes in its ph upon small additions of acid or base.sq1 Chapter 15 Lesson Plan Grade 12 402. The presence of a common ion decreases the dissociation. BQ1 Calculate the ph of 0.10M CH 3 COOH. Ka = 1.8 10-5. [H + ] = = ( )( ) = 1.34 10-3 M ph = 2.87 Calculate

More information

Chapter 17 Additional Aspects of

Chapter 17 Additional Aspects of Chemistry, The Central Science, 11th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 17 Additional Aspects of AP Chemistry 2014-15 North Nova Education Centre Mr. Gauthier

More information

Thinking Like a Chemist About Acids and Bases Part V. What are we going to learn today?

Thinking Like a Chemist About Acids and Bases Part V. What are we going to learn today? UNIT6-DAY7-LaB1230pm Wednesday, February 27, 2013 5:34 PM Thinking Like a Chemist About Acids and Bases Part V UNIT6 DAY7 What are we going to learn today? Review Buffers Explore Acid Base Titrations Explore

More information

Chapter 17 Additional Aspects of

Chapter 17 Additional Aspects of Chemistry, The Central Science, 11th edition Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten Chapter 17 Additional Aspects of John D. Bookstaver St. Charles Community College Cottleville,

More information

Applications of Aqueous Equilibria Chapter 15. Titration Curves & Indicators Sections 4-5

Applications of Aqueous Equilibria Chapter 15. Titration Curves & Indicators Sections 4-5 Applications of Aqueous Equilibria Chapter 15 Titration Curves & Indicators Sections 45 Strong Acid vs. Strong Base Titration Titrate 50.0 ml of 0.200 M HNO 3 with 0.100 M NaOH What is the ph when no NaOH

More information

Chapter 15 Acid-Base Equilibria

Chapter 15 Acid-Base Equilibria Chapter 15 Acid-Base Equilibria Acid-Base Equilibria 15.1 Solutions of Acids or Bases Containing a Common Ion A. Common Ion 1. Ion provided in solution by an aqueous acid (or base) as well as a salt a.

More information

Titration of a weak acid with strong base

Titration of a weak acid with strong base Titration of a weak acid with strong base - Objectives: - To study titration curves. - Determine the pka value of a weak acid. - Reinforce the understanding of buffers. - Titration Curves: - Titration

More information

The Common Ion Effect

The Common Ion Effect Chapter 17 ACID BASE EQUILIBRIA (Part I) Dr. Al Saadi 1 17.1 The Common Ion Effect A phenomenon known as the common ion effect states that: When a compound containing an ion in common with an already dissolved

More information

REPORT FORM ACID BASE EQUILIBRIA. Name

REPORT FORM ACID BASE EQUILIBRIA. Name REPORT FORM ACID BASE EQUILIBRIA Name Section A Write chemical equations to explain the results of the conductance experiments demonstrated by your instructor. Only write equations for conductive solutions.

More information

Titration a solution of known concentration, called a standard solution

Titration a solution of known concentration, called a standard solution Acid-Base Titrations Titration is a form of analysis in which we measure the volume of material of known concentration sufficient to react with the substance being analyzed. Titration a solution of known

More information

Determination of an Equilibrium Constant

Determination of an Equilibrium Constant Last updated 1/29/2014 - GES Learning Objectives Students will be able to: Determine the numerical value of an equilibrium constant from measured concentrations of all reaction species. Use an absorption

More information

Titration 2: CH 3 COOH Titrated with NaOH

Titration 2: CH 3 COOH Titrated with NaOH Titration 2: CH 3 COOH Titrated with NaOH Titration 1: Acid is CH 3 COOH, phenolphthalein as the indicator 1. Obtain about 60 ml of the standardized ( 0.1 M) NaOH solution. CAUTION: Sodium hydroxide solution

More information

What we learn from Chap 18

What we learn from Chap 18 Applications of Aqueous Equilibria Chapter 18 What we learn from Chap 18 18.2 This chapter is the third in the three-chapter sequence about equilibrium, this one building upon the core principles raised

More information

Chem 116 POGIL Worksheet - Week 11 - Solutions Titration. millimol NaOH added = millimol HCl initially present

Chem 116 POGIL Worksheet - Week 11 - Solutions Titration. millimol NaOH added = millimol HCl initially present Chem 116 POGIL Worksheet - Week 11 - Solutions Titration Key Questions 1. A 25.0-mL sample of 0.100 M HCl(aq) is titrated with 0.125 M NaOH(aq). How many milliliters of the titrant will be need to reach

More information

2] What is the difference between the end point and equivalence point for a monobasicmonoacid

2] What is the difference between the end point and equivalence point for a monobasicmonoacid 4 Titrations modified October 9, 2013 1] A solution of 0.100 M AgNO 3 is used to titrate a 100.00 ml solution of 0.100 M KCl. The K sp of AgCl is 1.8e-11 a) What is pag if 50.00 ml of the titrant is added

More information

Buffer Solutions. Buffer Solutions

Buffer Solutions. Buffer Solutions Buffer Solutions A buffer solution is comprised of a mixture of an acid (base) with its conjugate base (acid) that resists changes in ph when additional acid or base is added The Henderson-Hasselbalch

More information

Edexcel Chemistry A-level Topic 12 - Acid-Base Equilibria

Edexcel Chemistry A-level Topic 12 - Acid-Base Equilibria Edexcel Chemistry A-level Topic 12 - Acid-Base Equilibria Flashcards Define a Bronsted-Lowry acid Define a Bronsted-Lowry acid Proton donor Define a Bronsted-Lowry base Define a Bronsted-Lowry base Proton

More information

Review: Acid-Base Chemistry. Title

Review: Acid-Base Chemistry. Title Review: Acid-Base Chemistry Title Basics General properties of acids & bases Balance neutralization equations SA + SB water + salt Arrhenius vs. Bronsted-Lowry BL plays doubles tennis match with H+) Identify

More information

Applications of Aqueous Equilibrium Chapter 15. Common Ion Effect & Buffers Sections 1-3

Applications of Aqueous Equilibrium Chapter 15. Common Ion Effect & Buffers Sections 1-3 Applications of Aqueous Equilibrium Chapter 15 Common Ion Effect & Buffers Sections 1-3 Solutions of Acids or Bases Containing a Common Ion NaF Na + + F - HF H + + F - What effect does the NaF have on

More information

So, What Does it Indicate?

So, What Does it Indicate? So, What Does it Indicate? Introduction Phenolphthalein is a common indicator you may have used in a previous science course, such as Chemistry 130 or Chemistry 170. In solutions with a ph of less then

More information

AP CHEMISTRY NOTES 10-1 AQUEOUS EQUILIBRIA: BUFFER SYSTEMS

AP CHEMISTRY NOTES 10-1 AQUEOUS EQUILIBRIA: BUFFER SYSTEMS AP CHEMISTRY NOTES 10-1 AQUEOUS EQUILIBRIA: BUFFER SYSTEMS THE COMMON ION EFFECT The common ion effect occurs when the addition of an ion already present in the system causes the equilibrium to shift away

More information

Preparation of Standard Curves. Principle

Preparation of Standard Curves. Principle Preparation of Standard urves Principle Many laboratory tests require the measurement of concentration be evaluated or read in a photometer (colorimeter or spectrophotometer). Since these instruments are

More information

ph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor

ph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor ph calculations MUDr. Jan Pláteník, PhD Brønsted-Lowry concept of acids and bases Acid is a proton donor Base is a proton acceptor HCl(aq) + H 2 O(l) H 3 O + (aq) + Cl - (aq) Acid Base Conjugate acid Conjugate

More information

Chapter 16: Applications of Aqueous Equilibrium Part 2. Acid-Base Titrations

Chapter 16: Applications of Aqueous Equilibrium Part 2. Acid-Base Titrations Chapter 16: Applications of Aqueous Equilibrium Part 2 Acid-Base Titrations When you add an acid and a base together, a neutralization rxn occurs. In the lab, we do neutralization rxns all the time as

More information

Acid-Base Solutions - Applications

Acid-Base Solutions - Applications Acid-Base Solutions - Applications 1 The Common Ion Effect Consider the equilibrium established when acetic acid, HC 2 H 3 O 2, is added to water. CH 3 COOH(aq) + H 2 O(l) CH 3 COO - (aq) + H 3 O + (aq)

More information

ACID-BASE REACTIONS. Titrations Acid-Base Titrations

ACID-BASE REACTIONS. Titrations Acid-Base Titrations Page III-b-1 / Chapter Fourteen Part II Lecture Notes ACID-BASE REACTIONS Chapter (Part II A Weak Acid + Strong Base Titration Titrations In this technique a known concentration of base (or acid is slowly

More information

Copyright 2018 Dan Dill 1

Copyright 2018 Dan Dill 1 TP The expression for the equilibrium constant for the solubility equilibrium M 2 X 2 M X 2 is 1. sp 2 M X 2 / M 2 X 2. sp 2 M 2 X 2 / M 2 X 3. sp 2 M 2 X 2 4. sp M 2 X 2 Lecture 21 CH102 A1 (MWF 9:05

More information

APPLICATIONS OF AQUEOUS EQUILIBRIA. Chapter 15

APPLICATIONS OF AQUEOUS EQUILIBRIA. Chapter 15 APPLICATIONS OF AQUEOUS EQUILIBRIA Chapter 15 Acid-Base Equilibria Common Ion Effect in Acids and Bases Buffer SoluFons for Controlling ph Buffer Capacity ph-titrafon Curves Acid-Base TitraFon Indicators

More information

Make a mixture of a weak acid and its conjugate base (as the SALT) Make a mixture of a weak base and its conjugate acid (as the SALT)

Make a mixture of a weak acid and its conjugate base (as the SALT) Make a mixture of a weak base and its conjugate acid (as the SALT) 175 BUFFERS - resist ph change caused by either the addition of strong acid/base OR by dilution Made in one of two ways: Make a mixture of a weak acid and its conjugate base (as the SALT) Make a mixture

More information

Acid-Base Equilibria. 1.NH 4 Cl 2.NaCl 3.KC 2 H 3 O 2 4.NaNO 2. Acid-Ionization Equilibria. Acid-Ionization Equilibria

Acid-Base Equilibria. 1.NH 4 Cl 2.NaCl 3.KC 2 H 3 O 2 4.NaNO 2. Acid-Ionization Equilibria. Acid-Ionization Equilibria Acid-Ionization Equilibria Acid-Base Equilibria Acid ionization (or acid dissociation) is the reaction of an acid with water to produce hydronium ion (hydrogen ion) and the conjugate base anion. (See Animation:

More information

Chapter 16 Aqueous Ionic Equilibrium

Chapter 16 Aqueous Ionic Equilibrium Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Chapter 16 Aqueous Ionic Equilibrium Roy Kennedy Massachusetts Bay Community College Wellesley Hills, MA 2008, Prentice Hall The Danger of Antifreeze

More information

Chapter 17. Additional Aspects of Equilibrium

Chapter 17. Additional Aspects of Equilibrium Chapter 17. Additional Aspects of Equilibrium 17.1 The Common Ion Effect The dissociation of a weak electrolyte is decreased by the addition of a strong electrolyte that has an ion in common with the weak

More information

DATA SHEETS AND CALCULATIONS FOR ACIDS & BASES

DATA SHEETS AND CALCULATIONS FOR ACIDS & BASES Chemistry 112 Laboratory: Chemistry of Acids & Bases Page 73 DATA SHEETS AND CALCULATIONS FOR ACIDS & BASES Name Partner s Name Grade and Instructor Comments Part 1: Experimental Measurement Determining

More information

Preparation Of Different Buffer Solutions. BCH 312 [Practical]

Preparation Of Different Buffer Solutions. BCH 312 [Practical] Preparation Of Different Buffer Solutions BCH 312 [Practical] Introduction: All biochemical reactions occur under strict conditions of the concentration of hydrogen ion. Biological life cannot withstand

More information

Page 1 of 9 Chem 201 Lecture 6a Summer 09. Announcement: Fluoride experiment will replace the Cu-ASV experiment for those who have not yet done Cu-ASV

Page 1 of 9 Chem 201 Lecture 6a Summer 09. Announcement: Fluoride experiment will replace the Cu-ASV experiment for those who have not yet done Cu-ASV Page 1 of 9 Chem 201 Lecture 6a Summer 09 Announcement: Fluoride experiment will replace the Cu-ASV experiment for those who have not yet done Cu-ASV The protocol will be posted soon as all the typos are

More information

Mixtures of Acids and Bases

Mixtures of Acids and Bases Mixtures of Acids and Bases CH202, lab 6 Goals : To calculate and measure the ph of pure acid and base solutions. To calculate and measure the ph of mixtures of acid and base solutions. Safety : Hydrochloric

More information

Questions #4-5 The following two questions refer to the following system: A 1.0L solution contains 0.25M HF and 0.60M NaF (Ka for HF = 7.2 x 10-4 ).

Questions #4-5 The following two questions refer to the following system: A 1.0L solution contains 0.25M HF and 0.60M NaF (Ka for HF = 7.2 x 10-4 ). Multiple Choice 1) A solution contains 0.250 M HA (K a = 1.0 x 10-6 ) and 0.45 M NaA. What is the ph after 0.10 mole of HCl is added to 1.00L of this solution? a. 3.17 b. 3.23 c. 6.00 d. 10.77 e. 10.83

More information

Problem 1 C 6 H 5 [ COOH C 6 H[H 5 COO + ] - + H [ I C - x + x + x E x x x

Problem 1 C 6 H 5 [ COOH C 6 H[H 5 COO + ] - + H [ I C - x + x + x E x x x Problem 1 What is the ph of a 291mL sample of 2.993M benzoic acid (C 6 H 5 COOH) (K a =6.4x10 5 )? Write out acid dissociation reaction: C 6 H 5 COOH C 6 H 5 COO H Make an ICE chart since this is a weak

More information

Problem Set on Tracking Reaction Progress

Problem Set on Tracking Reaction Progress CHM 103 Problem Set on Tracking Reaction Progress Sinex 1. Consider the titration of a weak acid, HX, as given below. A weak acid sample of 216.1 mg was dissolved to make 15.00 ml solution. This was titrated

More information

Lecture Presentation. Chapter 16. Aqueous Ionic Equilibrium. Sherril Soman Grand Valley State University Pearson Education, Inc.

Lecture Presentation. Chapter 16. Aqueous Ionic Equilibrium. Sherril Soman Grand Valley State University Pearson Education, Inc. Lecture Presentation Chapter 16 Aqueous Ionic Equilibrium Sherril Soman Grand Valley State University The Danger of Antifreeze Each year, thousands of pets and wildlife species die from consuming antifreeze.

More information

Expt 4: Determination of Iron by Absorption Spectrophotometry Calibration solutions: Iron(II)ammonium sulfate = ferrous ammonium sulfate

Expt 4: Determination of Iron by Absorption Spectrophotometry Calibration solutions: Iron(II)ammonium sulfate = ferrous ammonium sulfate Expt 4: Determination of Iron by Absorption Spectrophotometry Calibration solutions: Iron(II)ammonium sulfate = ferrous ammonium sulfate FeSO 4 (NH 4 ) 2 SO 4 6H 2 O, M.W. = 392.14 g Stock 1 0.210 g in

More information

K w. Acids and bases 8/24/2009. Acids and Bases 9 / 03 / Ionization of water. Proton Jumping Large proton and hydroxide mobility

K w. Acids and bases 8/24/2009. Acids and Bases 9 / 03 / Ionization of water. Proton Jumping Large proton and hydroxide mobility Chapter 2 Water Acids and Bases 9 / 03 / 2009 1. How is the molecular structure of water related to physical and chemical behavior? 2. What is a Hydrogen Bond? 3Wh 3. What are Acids Aid and db Bases? 4.

More information

OCR (A) Chemistry A-level Topic Acids, Bases and Buffers

OCR (A) Chemistry A-level Topic Acids, Bases and Buffers OCR (A) Chemistry A-level Topic 5.1.3 - Acids, Bases and Buffers Flashcards Define a Bronsted-Lowry acid Define a Bronsted-Lowry acid Proton donor Define a Bronsted-Lowry base Define a Bronsted-Lowry base

More information

1. What is the poh of a 0.1 M HClO 4 solution? What kind of acid base problem was this?.

1. What is the poh of a 0.1 M HClO 4 solution? What kind of acid base problem was this?. Spring 009 CH0 Worksheet How to Systematically Work Harder and Harder Acid Base Calculations Exactly the Same Way: Proof that the Seven Steps to Solving Acid Base Problems Work Remove the spectator ions

More information