Acid-Base Titration Solution Key

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Acid-Base Titration Solution Key"

Transcription

1 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 is constant and that volumes are additive. (a) Write the equilibrium constant expression for the reaction above. K b = CH 3NH 3 [OH ] [CH 3 NH 2 ] (b) Determine the initial concentration of methylamine. Since the solution is a weak base, construct an ICE table [CH 3 NH 2 ] CH 3 NH 3 [OH ] Initial [CH 3 NH 2 ] i 0 0 Change x x x Equilibrium [CH 3 NH 2 ] i x x x Substitute the expression of the equilibrium concentrations for each chemical species into the equilibrium constant expression for K b. K b = CH 3NH 3 OH CH 3 NH 2 = x (x) = [CH 3 NH 2 ] i x Since we are looking for the initial concentration of methylamine, [CH 3 NH 2 ] i, the value of x must be known. In the problem, the [OH ] is given as M. This is equal to x. Hence, we can now calculate [CH 3 NH 2 ] i from the equation. Solving the equation, = [CH 3 NH 2 ] i [CH 3 NH 2 ] i = M

2 (c) Determine the percent ionization of methylamine in the above solution. Percent ionization is the percentage of the initial concentration of the base that dissociates to form CH 3 NH 3 and OH given by the following formula: % ionization = amount dissociated initial amount 100% = x [CH 3 NH 2 ] i 100% = % % ionization = 22. 7% (d) What is the number of moles of HCl that should be added to 100. ml of M CH3NH2 to produce a solution buffered at ph = A base buffer solution must contain both the weak base (CH3NH2) and its conjugate acid (CH3NH3 ). Adding HCl into the weak base solution will produce the conjugate acid as shown by the following net ionic equation. CH 3 NH 2 H CH 3 NH 3 The amount of HCl added must not exceed the initial concentration of the CH3NH2, otherwise, no buffer will be formed. The ratio of the weak base and its conjugate acid will determine the ph. In other words, the problem basically asks for the amount of HCl that must be added so that the ratio is just right to give a ph= Calculating ph of buffer solutions is easier with the use of the Henderson-Hasselbach equation: ph = pk a log [base] [acid] = pk a log [CH 3NH 2 ] [CH 3 NH 3 ] pk a = log K a. Since K a is not given, the value can be calculated using the following equation: K a = Kw where Kw = while K K b = Therefore b pk a =

3 If we let x = moles HCl added, the stoichiometry of the reaction is shown by the table below: Initial moles CH 3 NH 2 moles HCl moles CH 3 NH 3 (0.100 L)(0.100 M) = moles x 0 Change x x -x Final x 0 completely used up (Limiting Reactant) x Remember that in the log ratio, the moles of the species can be used instead of a concentration because the volume units will cancel out anyway. ph = pk a log [CH 3NH 2 ] [CH 3 NH 3 ] x = log x x = moles HCl

4 (e) ml of M CH3NH3Cl is titrated with M NaOH to the equivalence point and beyond the equivalence point. We have to identify the acid-base reaction involved in this particular titration. Notice that the acid in the problem is a salt. CH 3 NH 3 is the one that will react with theoh, Na and Cl - are weaker conjugates. CH 3 NH 3 OH CH 3 NH 2 H 2 O (i) Find the ph of a M CH3NH3Cl solution. Initially the flask only contains the acid salt solution (CH 3 NH 3 ). Hence, the ph can be solved from the dissociation of the acid salt in H2O using the ICE table below. CH 3 NH 3 H 2 O CH 3 NH 2 H 3 O CH 3 NH 3 [CH 3 NH 2 ] H 3 O Initial M 0 0 Change x x x Equilibrium x x x K a = K w K b = x x = x = M ph = log[ H 3 O ] = log = 5. 67

5 (ii) Find the volume of NaOH needed to reach the equivalence point. CH 3 NH 3 OH CH 3 NH 2 H 2 O At the equivalence point, there is no limiting or excess reactant, both the CH 3 NH 3 and OH completely used up in the reaction. Hence, to calculate the volume needed to reach equivalent point, the following equation can be used because the ratio of acid to base is 1:1 moles CH 3 NH 3 = moles OH (C V) CH3 NH 3 = (C V) OH M ml = M V OH V OH = ml (iii) Find the ph at the equivalence point. At equivalence point, the major species that would affect the ph is only CH 3 NH 2. Since this is a weak base and can dissociate in water, the ph is expected to be greater than 7. Since the moles of CH 3 NH 3 that reacted is the same number of moles of CH 3 NH 2 produced, moles CH 3 NH 3 = M L = moles moles CH 3 NH 2 = moles CH 3 NH 2 H 2 O CH 3 NH 3 OH The ph can be calculated from the ICE table of the dissociation of the weak base. The initial concentration of CH 3 NH 2 must be calculated based on the number of moles produced and the total volume (original volume of the acid salt volume of the base added) of the solution at this point. [CH 3 NH 2 ] i = moles = M L L

6 [CH 3 NH 2 ] CH 3 NH 3 [OH ] Initial Change x x x Equilibrium x x x K b = x 2 = x x = M poh = log = 2.27 ph = (iv) Sketch a rough curve for the above titration on the graph below and indicate the initial ph, the ph at half-way to the equivalence point and the ph at the equivalence point. A titration curve can be sketched based on four points only. The initial point The volume of NaOH added is zero. The initial ph is calculated from part (e)(i), ph = 5.67 The equivalence point The volume of NaOH added is ml based on calculation in part (e)(ii) The ph at equivalence point is calculated from part (e)(iii), ph=11.73 The half-equivalence point The volume is half of the volume at equivalence point, ml Since the ratio of the base and acid is equal to 1 at this point, the Henderson- Hasselbach equation reduces to ph = pka Hence, the ph at half-equivalence point is Beyond equivalence Assume a volume greater than the equivalence volume. The difference between the assumed volume and the equivalence volume is the excess NaOH unreacted in the solution. This will determine the ph of the solution. Let s say, we have added ml. The excess NaOH would then be ml. Hence the excess base would be ml.

7 The concentration of the base must then be recalculated considering the total volume of the solution at this point. OH = moles excess NaOH total volume of solution = L (0.100 M) = M (0.125 L L) poh = log = 1.54 ph = =

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

AS Demonstrate understanding of equilibrium principles in aqueous systems. Collated Buffer Questions

AS Demonstrate understanding of equilibrium principles in aqueous systems. Collated Buffer Questions 2016: AS 91392 Demonstrate understanding of equilibrium principles in aqueous systems No separate buffer question asked. 2015: 3 Collated Buffer Questions 20.0 ml of 0.258 mol L 1 hydrofluoric acid, HF,

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

Department of Chemistry University of Texas at Austin

Department of Chemistry University of Texas at Austin Titrations and Buffers Supplemental Worksheet KEY HINT: When calculating the ph of a solution use the following 3 steps Titrations The next six problems represent many points along a titration curve of

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

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

Acids and Bases Written Response

Acids and Bases Written Response Acids and Bases Written Response January 1999 4. Consider the salt sodium oxalate, Na2C2O4. a) Write the dissociation equation for sodium oxalate. (1 mark) b) A 1.0M solution of sodium oxalate turns pink

More information

CHEMISTRY 1AA3 Tutorial 2 Answers - WEEK E WEEK OF JANUARY 22, (i) What is the conjugate base of each of the following species?

CHEMISTRY 1AA3 Tutorial 2 Answers - WEEK E WEEK OF JANUARY 22, (i) What is the conjugate base of each of the following species? CHEMISTRY 1AA3 Tutorial 2 Answers - WEEK E WEEK OF JANUARY 22, 2001 M.A. Brook B.E. McCarry A. Perrott 1. (i) What is the conjugate base of each of the following species? (a) H 3 O + (b) NH 4 + (c) HCl

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

Secondary Topics in Equilibrium

Secondary Topics in Equilibrium Secondary Topics in Equilibrium Outline 1. Common Ions 2. Buffers 3. Titrations Review 1. Common Ions Include the common ion into the equilibrium expression Calculate the molar solubility in mol L -1 when

More information

2011 AP CHEMISTRY FREE-RESPONSE QUESTIONS (Form B)

2011 AP CHEMISTRY FREE-RESPONSE QUESTIONS (Form B) 2011 AP CHEMISTRY FREE-RESPONSE QUESTIONS (Form B) 5. A student is instructed to prepare 100.0 ml of 1.250 M NaOH from a stock solution of 5.000 M NaOH. The student follows the proper safety guidelines.

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 17 Homework Problem Solutions

Chapter 17 Homework Problem Solutions Chapter 17 Homework Problem Solutions 17.40 D 2 O D + + OD, K w = [D + ] [OD ] = 8.9 10 16 Since [D + ] = [OD ], we can rewrite the above expression to give: 8.9 10 16 = ([D + ]) 2, [D + ] = 3.0 10 8 M

More information

Chemical Equilibrium. Many reactions are, i.e. they can occur in either direction. A + B AB or AB A + B

Chemical Equilibrium. Many reactions are, i.e. they can occur in either direction. A + B AB or AB A + B Chemical Equilibrium Many reactions are, i.e. they can occur in either direction. A + B AB or AB A + B The point reached in a reversible reaction where the rate of the forward reaction (product formation,

More information

Homework #7 Chapter 8 Applications of Aqueous Equilibrium

Homework #7 Chapter 8 Applications of Aqueous Equilibrium Homework #7 Chapter 8 Applications of Aqueous Equilibrium 15. solution: A solution that resists change in ph when a small amount of acid or base is added. solutions contain a weak acid and its conjugate

More information

Chemical Equilibrium

Chemical Equilibrium Chemical Equilibrium Many reactions are reversible, i.e. they can occur in either direction. A + B AB or AB A + B The point reached in a reversible reaction where the rate of the forward reaction (product

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

Acids, Bases and Buffers

Acids, Bases and Buffers 1 Acids, Bases and Buffers Strong vs weak acids and bases Equilibrium as it relates to acids and bases ph scale: [H+(aq)] to ph, poh, etc ph of weak acids ph of strong acids Conceptual about oxides (for

More information

Unit The mw of Na 2 CO 3 is : Na=23, O=16, C=12 A) 140 B) 106 C) 96 D) 100 E) 60

Unit The mw of Na 2 CO 3 is : Na=23, O=16, C=12 A) 140 B) 106 C) 96 D) 100 E) 60 Unit 2 1- The mw of Na 2 CO 3 is : Na=23, O=16, C=12 A) 140 B) 106 C) 96 D) 100 E) 60 2- How many grams of Na 2 CO 3 (mw = 106 ) A) 318 B) 0.028 C) 134 D) 201 E) 67 in 3 moles, 3- Calculate the normal

More information

Acid and Base Titrations - Equation Guide

Acid and Base Titrations - Equation Guide Acid and Base Titrations - Equation Guide Strong Acid + Strong Base: Initial Region: ph = - log (n sa / V sa ) or ph = - log (C sa ) Pre-Equivalence Region: ph = - log sa # or ph = - log Equivalence: ph

More information

Grace King High School Chemistry Test Review

Grace King High School Chemistry Test Review CHAPTER 19 Acids, Bases & Salts 1. ACIDS Grace King High School Chemistry Test Review UNITS 7 SOLUTIONS &ACIDS & BASES Arrhenius definition of Acid: Contain Hydrogen and produce Hydrogen ion (aka proton),

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

Acid-Base Equilibria and Solubility Equilibria

Acid-Base Equilibria and Solubility Equilibria Acid-Base Equilibria and Solubility Equilibria Acid-Base Equilibria and Solubility Equilibria Homogeneous versus Heterogeneous Solution Equilibria (17.1) Buffer Solutions (17.2) A Closer Look at Acid-Base

More information

School of Chemistry, University of KwaZulu-Natal, Howard College Campus, Durban. CHEM191 Tutorial 1: Buffers

School of Chemistry, University of KwaZulu-Natal, Howard College Campus, Durban. CHEM191 Tutorial 1: Buffers School of Chemistry, University of KwaZulu-Natal, Howard College Campus, Durban CHEM191 Tutorial 1: Buffers Preparing a Buffer 1. How many moles of NH 4 Cl must be added to 1.0 L of 0.05 M NH 3 to form

More information

Arrhenius, Bronstead-Lowry, Intro to ph scale

Arrhenius, Bronstead-Lowry, Intro to ph scale Unit 9 Acid/Base Equilibrium In Class Problems and Notes Arrhenius, Bronstead-Lowry, Intro to ph scale Arrhenius acid and Arrhenius base. An acid is a substance which, when dissolved in water, increases

More information

Chemistry 12 UNIT 4 ACIDS AND BASES

Chemistry 12 UNIT 4 ACIDS AND BASES Chemistry 12 UNIT 4 ACIDS AND BASES PACKAGE #6 TITRATION -allows you to react measured amounts of a solution with a known volume of another solution until an equivalence point is reached. Recall from Indicators

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

EXAM 2 Free Response. K c. C. Calculate Q and indicate which direction the reaction will proceed as it moves towards equilibrium (2 points)

EXAM 2 Free Response. K c. C. Calculate Q and indicate which direction the reaction will proceed as it moves towards equilibrium (2 points) Put the first three letters of your LASTNAME in the boxes EXAM 2 Free Response Name: Sparks EID: CH302 Spring 2014 Version Number: Answers must appear on this paper in the space provided. You should show

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

Ch 16 and 17 Practice Problems

Ch 16 and 17 Practice Problems Ch 16 and 17 Practice Problems The following problems are intended to provide you with additional practice in preparing for the exam. Questions come from the textbook, previous quizzes, previous exams,

More information

1.12 Acid Base Equilibria

1.12 Acid Base Equilibria .2 Acid Base Equilibria BronstedLowry Definition of acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that can

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

Chapter 4: Chemical Quantities and Aqueous Reactions

Chapter 4: Chemical Quantities and Aqueous Reactions Chapter 4: Chemical Quantities and Aqueous Reactions C (s) + O 2 (g) CO 2 (g) CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 0 (g) 2 C 8 H 18 (g) + 25 O 2 (g) 16 CO 2 (g) + 18 H 2 0 (g) Stoichiometry Calculations

More information

A buffer is a an aqueous solution formed from a weak conjugate acid-base pair that resists ph change upon the addition of another acid or base.

A buffer is a an aqueous solution formed from a weak conjugate acid-base pair that resists ph change upon the addition of another acid or base. 1 A buffer is a an aqueous solution formed from a weak conjugate acid-base pair that resists ph change upon the addition of another acid or base. after addition of H 3 O + equal concentrations of weak

More information

Acids And Bases. H + (aq) + Cl (aq) ARRHENIUS THEORY

Acids And Bases. H + (aq) + Cl (aq) ARRHENIUS THEORY Acids And Bases A. Characteristics of Acids and Bases 1. Acids and bases are both ionic compounds that are dissolved in water. Since acids and bases both form ionic solutions, their solutions conduct electricity

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

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

Follow- up Wkst Acid and Base ph Calculations

Follow- up Wkst Acid and Base ph Calculations CH302 LaBrake and Vanden Bout 2-23- 12 Follow- up Wkst Acid and Base ph Calculations For each of the following solutions: Write a chemical equation, identify the limiting reactant (if there is one), and

More information

Review of Chemistry 11

Review of Chemistry 11 Review of Chemistry 11 HCl C 3 H 8 SO 2 NH 4 Cl KOH H 2 SO 4 H 2 O AgNO 3 PbSO 4 H 3 PO 4 Ca(OH) 2 Al(OH) 3 P 2 O 5 Ba(OH) 2 CH 3 COOH 1. Classify the above as ionic or covalent by making two lists. Describe

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

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

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

AP Chapter 15 & 16: Acid-Base Equilibria Name

AP Chapter 15 & 16: Acid-Base Equilibria Name AP Chapter 15 & 16: Acid-Base Equilibria Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. AP Chapter 15 & 16: Acid-Base Equilibria 2 Warm-Ups (Show

More information

ph + poh = 14 G = G (products) G (reactants) G = H T S (T in Kelvin)

ph + poh = 14 G = G (products) G (reactants) G = H T S (T in Kelvin) JASPERSE CHEM 210 PRACTICE TEST 3 VERSION 2 Ch. 17: Additional Aqueous Equilibria Ch. 18: Thermodynamics: Directionality of Chemical Reactions Key Equations: For weak acids alone in water: [H + ] = K a

More information

Chemistry 12 April 2000 Provincial Examination

Chemistry 12 April 2000 Provincial Examination Chemistry 12 April 2000 Provincial Examination ANSWER KEY / SCORING GUIDE CURRICULUM: Organizers 1. Reaction Kinetics 2. Dynamic Equilibrium 3. Solubility Equilibria 4. Acids, Bases, and Salts 5. Oxidation

More information

STOICHIOMETRY OF ACID-BASE NEUTRALIZATION REACTIONS. Ms. Grobsky

STOICHIOMETRY OF ACID-BASE NEUTRALIZATION REACTIONS. Ms. Grobsky STOICHIOMETRY OF ACID-BASE NEUTRALIZATION REACTIONS Ms. Grobsky ACID-BASE NEUTRALIZATION REACTIONS Remember, an acid-base neutralization reaction is a special type of double replacement reaction in which

More information

1. Know and be capable of applying the Bronsted-Lowery model of acids and bases (inculdig the concepts related to conjugate acid-base pairs.

1. Know and be capable of applying the Bronsted-Lowery model of acids and bases (inculdig the concepts related to conjugate acid-base pairs. Acid-Base Equilibria You have just completed a chapter on equilibrium. That chapter focused primarily on gas phase reactions (with a few exceptions). This section on Acid-Base equilibria (along with the

More information

Enduring Understanding

Enduring Understanding Big Idea #6 Big Idea 6: Any bond or intermolecular attraction that can be formed can be broken. These two processes are in a dynamic competition, sensitive to initial conditions and external disturbances.

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which one of the following is the weakest acid? 1) A) HF (Ka = 6.8 10-4) B) HNO2 (Ka

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

Stoichiometry of Acid-Base Neutralization Reactions. Ms. Grobsky

Stoichiometry of Acid-Base Neutralization Reactions. Ms. Grobsky Stoichiometry of Acid-Base Neutralization Reactions Ms. Grobsky Revisit of Acid-Base Neutralization Reactions Remember, an acid-base neutralization reaction is a special type of double replacement reaction

More information

capable of neutralizing both acids and bases

capable of neutralizing both acids and bases Buffers Buffer n any substance or mixture of compounds that, added to a solution, is capable of neutralizing both acids and bases without appreciably changing the original acidity or alkalinity of the

More information

CALCULATING THE ph OF WEAK ACID SOLUTIONS

CALCULATING THE ph OF WEAK ACID SOLUTIONS TUTORIAL 10 Calculating ph of Weak Acid Solutions Percent Ionization Solutions of Bases Acid-Base Properties of Ions and Salts CALCULATING THE ph OF WEAK ACID SOLUTIONS Tro - Sections 15.6 to 15.8 FORMAL

More information

Chemistry 12 Provincial Exam Workbook Unit 04: Acid Base Equilibria. Multiple Choice Questions

Chemistry 12 Provincial Exam Workbook Unit 04: Acid Base Equilibria. Multiple Choice Questions R. Janssen, MSEC Chemistry 1 Provincial Workbook (Unit 0), P. 1 / 69 Chemistry 1 Provincial Exam Workbook Unit 0: Acid Base Equilibria Multiple Choice Questions 1. Calculate the volume of 0.00 M HNO needed

More information

Chapter 15, Applications of Aqueous Equilibria

Chapter 15, Applications of Aqueous Equilibria Chapter 15, Applications of Aqueous Equilibria We will focus on 3 areas: 1) titrations 2) buffers (incl. the Henderson- Hasselbalch Transformation), 3) solubility equilibria. 1 I. Neutralization Reactions

More information

ACIDS AND BASES CONTINUED

ACIDS AND BASES CONTINUED ACIDS AND BASES CONTINUED WHAT HAPPENS WHEN AN ACID DISSOLVED IN WATER? Water acts as a Brønsted Lowry base and abstracts a proton (H+) from the acid. As a result, the conjugate base of the acid and a

More information

Acids and Bases. Reviewing Vocabulary CHAPTER ASSESSMENT CHAPTER 19. Compare and contrast each of the following terms.

Acids and Bases. Reviewing Vocabulary CHAPTER ASSESSMENT CHAPTER 19. Compare and contrast each of the following terms. Acids and Bases Reviewing Vocabulary Compare and contrast each of the following terms. 1. Arrhenius model, Brønsted-Lowry model 2. acid ionization constant, base ionization constant 3. conjugate acid,

More information

Unit 4-1 Provincial Practice Questions Page 1

Unit 4-1 Provincial Practice Questions Page 1 Page 1 Page 2 Page 3 Page 4 Page 5 1.00 Page 6 Page 7 Page 8 55. The conjugate base of HAsO 4 2 is A. H 3 O + B. 3 AsO 4 C. H 3 AsO 4 D. H 2 AsO 4 56. Consider the following acidbase equilibrium: HC 6

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

The ph of aqueous salt solutions

The ph of aqueous salt solutions The ph of aqueous salt solutions Sometimes (most times), the salt of an acid-base neutralization reaction can influence the acid/base properties of water. NaCl dissolved in water: ph = 7 NaC 2 H 3 O 2

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

chemrevise.org 20/08/2013 Titration curves N Goalby Chemrevise.org 25 cm 3 of base

chemrevise.org 20/08/2013 Titration curves N Goalby Chemrevise.org 25 cm 3 of base chemrevise.org 20/08/203 Titration curves N Goalby Chemrevise.org Titration curves 3 Titration curves are made by measuring the of the solution in the conical flask each time a small amount of acid or

More information

AP Chemistry. CHAPTER 17- Buffers and Ksp 17.1 The Common Ion Effect Buffered Solutions. Composition and Action of Buffered Solutions

AP Chemistry. CHAPTER 17- Buffers and Ksp 17.1 The Common Ion Effect Buffered Solutions. Composition and Action of Buffered Solutions AP Chemistry CHAPTER 17- Buffers and Ksp 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 electrolyte.

More information

ph + poh = 14 G = G (products) G (reactants) G = H T S (T in Kelvin) 1. Which of the following combinations would provide buffer solutions?

ph + poh = 14 G = G (products) G (reactants) G = H T S (T in Kelvin) 1. Which of the following combinations would provide buffer solutions? JASPERSE CHEM 210 PRACTICE TEST 3 VERSION 3 Ch. 17: Additional Aqueous Equilibria Ch. 18: Thermodynamics: Directionality of Chemical Reactions Key Equations: For weak acids alone in water: [H + ] = K a

More information

19.3 Strengths of Acids and Bases > Chapter 19 Acids, Bases, and Salts Strengths of Acids and Bases

19.3 Strengths of Acids and Bases > Chapter 19 Acids, Bases, and Salts Strengths of Acids and Bases Chapter 19 Acids, Bases, and Salts 19.1 Acid-Base Theories 19.2 Hydrogen Ions and Acidity 19.3 Strengths of Acids and Bases 19.4 Neutralization Reactions 19.5 Salts in Solution 1 Copyright Pearson Education,

More information

Chemistry 102 Summary July 24 th. Question: Sketch a generic curve for a diprotic acid titration with a strong base. Answer:

Chemistry 102 Summary July 24 th. Question: Sketch a generic curve for a diprotic acid titration with a strong base. Answer: Polyprotic Acid Titrations * Chemistry 102 Summary July 24 th Question: Sketch a generic curve for a diprotic acid titration with a strong base. Answer: Question: Consider the titration curve of 50.0 ml

More information

IB Chemistry ABS Introduction An acid was initially considered a substance that would produce H + ions in water.

IB Chemistry ABS Introduction An acid was initially considered a substance that would produce H + ions in water. IB Chemistry ABS Introduction An acid was initially considered a substance that would produce H + ions in water. The Brønsted-Lowry definition of an acid is a species that can donate an H + ion to any

More information

1 Chapter 19 Acids, Bases, and Salts

1 Chapter 19 Acids, Bases, and Salts 1 Chapter 19 Acids, Bases, and Salts ACID-BASE THEORIES Acids and bases are all around us and part of our everyday life (ex. bodily functions, vinegar, carbonated drinks, citrus fruits, car batteries,

More information

2/4/2016. Chapter 15. Chemistry: Atoms First Julia Burdge & Jason Overby. Acid-Base Equilibria and Solubility Equilibria The Common Ion Effect

2/4/2016. Chapter 15. Chemistry: Atoms First Julia Burdge & Jason Overby. Acid-Base Equilibria and Solubility Equilibria The Common Ion Effect Chemistry: Atoms First Julia Burdge & Jason Overby 17 Acid-Base Equilibria and Solubility Equilibria Chapter 15 Acid-Base Equilibria and Solubility Equilibria Kent L. McCorkle Cosumnes River College Sacramento,

More information

(aq)], does not contain sufficient base [C 2 H 3 O 2. (aq)] to be a buffer. If acid is added, there is too little conjugate base [C 2 H 3 O 2

(aq)], does not contain sufficient base [C 2 H 3 O 2. (aq)] to be a buffer. If acid is added, there is too little conjugate base [C 2 H 3 O 2 PURPOSE: 1. To understand the properties of buffer solutions. 2. To calculate the ph of buffer solutions and compare the calculated values with the experimentally determined ph values. PRINCIPLES: I. Definition,

More information

General Chemistry II CHM 1046 E Exam 2

General Chemistry II CHM 1046 E Exam 2 General Chemistry II CHM 1046 E Exam 2 Dr. Shanbhag Name: 1. The formation of ammonia from elemental nitrogen and hydrogen is an exothermic process. N 2 (g) + 3 H 2 (g) 2 NH 3 (g) H= -92.2 kj Which of

More information

CHEMISTRY 115 EXAM 2(A)

CHEMISTRY 115 EXAM 2(A) Summer 2003 CHEMISTRY 115 EXAM 2(A) 1. The reaction 2A B+C was found to second order in the concentration of A. What is the change in the reaction rate, Rate(t)/Rate(0), in the time interval from 0 to

More information

4. Acid Base Equilibria

4. Acid Base Equilibria 4. Acid Base Equilibria BronstedLowry Definition of acid Base behaviour A BronstedLowry acid is defined as a substance that can donate a proton. A BronstedLowry base is defined as a substance that can

More information

5.1 Module 1: Rates, Equilibrium and ph

5.1 Module 1: Rates, Equilibrium and ph 5.1 Module 1: Rates, Equilibrium and ph 5.1.1 How Fast? The rate of reaction is defined as the change in concentration of a substance in unit time Its usual unit is mol dm 3 s 1 When a graph of concentration

More information

Institute for Competitive Examinations

Institute for Competitive Examinations INSTITUTE FOR COMETITIVE EXAMINATIONS DELHI CENTRES: E-6, Defence Colony New Delhi - 11004. h.: 4614, 46144. B-1/6, Main Nazafgarh Road, Janakpuri, New Delhi - 110058. h.: 011-557111/1/1/14. NOIDA CENTRE:

More information

Calorimetry, Heat and ΔH Problems

Calorimetry, Heat and ΔH Problems Calorimetry, Heat and ΔH Problems 1. Calculate the quantity of heat involved when a 70.0g sample of calcium is heated from 22.98 C to 86.72 C. c Ca= 0.653 J/g C q = 2.91 kj 2. Determine the temperature

More information

Water. Water participates in H-bonding with biomolecules.

Water. Water participates in H-bonding with biomolecules. Water Most biochemical reactions occur in an aqueous environment. Water is highly polar because of its bent geometry. Water is highly cohesive because of intermolecular hydrogen bonding. Water participates

More information

Acid Base Titrations

Acid Base Titrations ChemActivity CA47b Acid Base Titrations Model 1 Titration of a strong acid with a strong base. 20.00 ml of HNO 3 is titrated with 0.10 M NaOH. The acid-base reaction is The net ionic reaction is HNO 3

More information

Titration Curves. What is in the beaker at each stage of a titration? Beaker A Beaker B Beaker C Beaker D. 20 ml NaOH Added

Titration Curves. What is in the beaker at each stage of a titration? Beaker A Beaker B Beaker C Beaker D. 20 ml NaOH Added Why? Titration Curves What is in the beaker at each stage of a titration? Titration is a very useful technique for determining the properties of an unknown solution. The unknown is reacted with a known

More information

Volume NaOH Delivered (ml)

Volume NaOH Delivered (ml) Chemistry Spring 011 Exam 3: Chapters 8-10 Name 80 Points Complete five (5) of the following problems. Each problem is worth 16 points. CLEARLY mark the problems you do not want graded. You must show your

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

AP Chemistry - Packet #1 - Equilibrium. 1) a) 5 points K p = (P NH3 ) (P H2S )

AP Chemistry - Packet #1 - Equilibrium. 1) a) 5 points K p = (P NH3 ) (P H2S ) 1) a) 5 points K p = (P NH3 ) (P H2S ) P NH3 = P H2S = (0.659 atm / 2) = 0.330 atm K p = (0.330 atm) (0.330 atm) = 0.109 atm 2 b) 5 points P NH3 = 2 P H2S (2x) (x) = 0.109 x = 0.233 atm = P H2S 2x = 0.466

More information

Solutions 4a (Chapter 4 problems)

Solutions 4a (Chapter 4 problems) Solutions 4a (Chapter 4 problems) Chem151 [Kua] 4.10 A balanced chemical equation must have equal numbers of atoms of each element on each side of the arrow. Balance each element in turn, beginning with

More information

K A K B = K W pk A + pk B = 14

K A K B = K W pk A + pk B = 14 Relationship between the ionization constants of an acid and its conjugate base HCN (aq) H 2 O(l) CN (aq) H O (aq) Conjugate couple The product between of an acid and of its conjugate base is : p p 14

More information

Buffers. How can a solution neutralize both acids and bases? Beaker B: 100 ml of 1.00 M HCl. HCl (aq) + H 2 O H 3 O 1+ (aq) + Cl 1 (aq)

Buffers. How can a solution neutralize both acids and bases? Beaker B: 100 ml of 1.00 M HCl. HCl (aq) + H 2 O H 3 O 1+ (aq) + Cl 1 (aq) Buffers How can a solution neutralize both acids and bases? Why? Buffer solutions are a mixture of substances that have a fairly constant ph regardless of addition of acid or base. They are used in medicine,

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

AP Chemistry: Acid-Base Chemistry Practice Problems

AP Chemistry: Acid-Base Chemistry Practice Problems Name AP Chemistry: Acid-Base Chemistry Practice Problems Date Due Directions: Write your answers to the following questions in the space provided. For problem solving, show all of your work. Make sure

More information

Ch 15, Applications of Aq Equilibria

Ch 15, Applications of Aq Equilibria Ch 15, Applications of Aq Equilibria We will focus on 3 areas: 1) buffers (incl. Henderson-Hasselbalch Transformation) 2) titrations 3) solubility equilibria 1 I. Neutralization Reactions A. Strong acid-strong

More information

CHM 1046 FINAL REVIEW

CHM 1046 FINAL REVIEW CHM 1046 FINAL REVIEW Prepared & Presented By: Marian Ayoub PART II Chapter Description 14 Chemical Equilibrium 15 Acids and Bases 16 Acid-Base Equilibrium 17 Solubility and Complex-Ion Equilibrium 19

More information

Practice Test - Chapter 13, 14, 15

Practice Test - Chapter 13, 14, 15 Practice Test - Chapter 13, 14, 15 1. For which of the following values of the equilibrium constant does the reaction go the farthest to completion? a. 10 5 b. 10 3 c. 10 0 d. 10-3 e. 10-5 2. Carbon disulfide

More information

(Label the Conjugate Pairs) Water in the last example acted as a Bronsted-Lowry base, and here it is acting as an acid. or

(Label the Conjugate Pairs) Water in the last example acted as a Bronsted-Lowry base, and here it is acting as an acid. or Chapter 16 - Acid-Base Equilibria Arrhenius Definition produce hydrogen ions in aqueous solution. produce hydroxide ions when dissolved in water. Limits to aqueous solutions. Only one kind of base. NH

More information

ANSWERS Unit 14: Review Acids and Bases

ANSWERS Unit 14: Review Acids and Bases ANSWERS Unit 14: Review Acids and Bases 1) CH 3 COOH(aq) + H 2 0(l) H 3 0 + (aq) + CH 3 COO - (aq) In the equilibrium above, what are the two conjugate bases? A. CH 3 COOH and H 2 0 B. CH 3 COO - and H

More information

Chapter 15 - Applications of Aqueous Equilibria

Chapter 15 - Applications of Aqueous Equilibria Neutralization: Strong Acid-Strong Base Chapter 15 - Applications of Aqueous Equilibria Molecular: HCl(aq) + NaOH(aq) NaCl(aq) + H 2 O(l) SA-SB rxn goes to completion (one-way ) Write ionic and net ionic

More information

Problem Solving. ] Substitute this value into the equation for poh.

Problem Solving. ] Substitute this value into the equation for poh. Skills Worksheet Problem Solving In 1909, Danish biochemist S. P. L Sørensen introduced a system in which acidity was expressed as the negative logarithm of the H concentration. In this way, the acidity

More information

2017 SUMMER ASSIGNMENT AP CHEMISTRY

2017 SUMMER ASSIGNMENT AP CHEMISTRY 2017 SUMMER ASSIGNMENT AP CHEMISTRY - This summer work packet is essentially a review of all material covered during Honor Chemistry. It must be completed prior to the first day of class. The problems

More information

What is the correct name and bonding of BF 3? What is the correct name and bonding of BF 3?

What is the correct name and bonding of BF 3? What is the correct name and bonding of BF 3? What is the correct name and bonding of BF 3? 1. boron trifluoride, covalent compound 2. boron trifluoride, ionic compound 3. boron fluoride, covalent compound 4. boron fluoride, ionic compound What is

More information

Chapter 17. Additional Aspects of Aqueous Equilibria. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT

Chapter 17. Additional Aspects of Aqueous Equilibria. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT Lecture Presentation Chapter 17 Additional Aspects of James F. Kirby Quinnipiac University Hamden, CT Effect of Acetate on the Acetic Acid Equilibrium Acetic acid is a weak acid: CH 3 COOH(aq) H + (aq)

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 8: Applications of Aqueous Equilibria

Chapter 8: Applications of Aqueous Equilibria Chapter 8: Applications of Aqueous Equilibria 8.1 Solutions of Acids or Bases Containing a Common Ion 8.2 Buffered Solutions 8.3 Exact Treatment of Buffered Solutions 8.4 Buffer Capacity 8.5 Titrations

More information

Acids, Bases, and Salts Review for Sections

Acids, Bases, and Salts Review for Sections 1. Consider the following: Review for Sections 4.1 4.9 I H 2 CO 3 + F HCO 3 + HF 2 II HCO 3 + HC 2 O 4 H 2 CO 3 + C 2 O 4 2 III HCO 3 + H 2 C 6 H 6 O 7 H 2 CO 3 + HC 6 H 5 O 7 The HCO 3 is a base in A.

More information