# Solubility Equilibria

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Chapter 17: Acid-Base Equilibria and Solubility Equilibria Key topics: Common ion effect Buffers Acid-base equilibria Solubility equilibria; complex ion formation The Common Ion Effect If we have two solutes each containing the same ion, the equilibrium is affected. This is called the common ion effect. Consider adding acetic acid (CH 3 COOH) and sodium acetate (NaCH 3 COO) to water. The acetate anion from sodium acetate will inhibit acetic acid from dissociating (Le Chatelier). First consider the situation with only acetic acid, at 0.10 M CH 3 COOH H + + CH3COO Initial Change -x +x +x Equilibrium x x x K a = = x x x ) x = which means the ph = 2.87 and the % ionization = 1.34% Next, consider adding moles of sodium acetate to 1.00 L of our acetic acid solution (assume volume does not change).

2 CH 3 COOH H + + CH3COO Initial x x 10 2 Change +x -x -x Equilibrium x 1.34 x x x x (note: the equilibrium must shift to the left from Le Chatelier) K a = ( x)( x) = ) x = x This gives [H + ] = 3.5 x 10 5 (using the quadratic equation) which means the ph = 4.46 and the % ionization = 0.035% The common ion effect is significant! Comment: The last calculation was hard because we had to use the quadratic equation. We can redo the last calculation by adding both of our solutes at the same time. This simplifies the math but does not affect the final equilibrium. CH 3 COOH H + + CH3COO Initial Change -x +x +x Equilibrium x x x K a = = (x)( x) 0.10 x (x)(0.050) 0.10 ) x = Buffer Solutions A buffer is a solution that contains comparable amounts of a weak acid and its conjugate base, or a weak base and its conjugate acid. Buffers resist changes in ph upon addition of acid or base.

3 Consider a buffer consisting of HA and A (weak acid/base) If we add a strong acid: H + + A HA The strong acid is converted to a weak acid: minimal ph shift If we add a strong base: OH + HA A + H 2 O The strong base is converted to a weak base: minimal ph shift We will use the acetate buffer to illustrate: Suppose we have 1 L of a solution that is 1 M acetic acid and 1 M sodium acetate. CH 3 COOH H + + CH3COO Initial Change -x +x +x Equilibrium 1.0 x x x K a = = (x)(1.0+x) 1.0 x x ) x = so the ph = 4.74 Now add 0.10 mol of HCl (neglect the volume change) Note: Adding 0.10 mol of HCl to pure water gives ph = 1.00 Strategy: assume all the H+ is consumed, and then allow H+ to be regenerated by the buffer. H + added: 0.1 mol 1.0 mol 1.0 mol H + + CH 3 COO CH 3 COOH H+ consumed: 0 mol 0.9 mol 1.1 mol CH 3 COOH H + + CH3COO Initial Change -x +x +x Equilibrium 1.1 x x x

4 K a = = (x)(0.9+x) (x)(0.9) 1.1 x 1.1 so the ph is 4.66 (a change of 0.08 ph units) ) x = We can derive a simple equation for buffer calculations: For HA H + + A we have K a = [H+ ][A ] [HA] ) log[h + ] = log K a + log [HA] [A ] ) ph = pk a + log [A ] [HA] =pk a + log ) [H + ]= K a[ha] [A ] [conjugate base] [weak acid] This is called the Henderson Hasselbalch equation. Important points: 1. x is small, so we can use the initial [ ] for HA and A 2. since you have a ratio, you can use M or moles 3. dilution won t change [A ] / [HA], so ph won t change For a weak base / conjugate acid buffer it reads: [conjugate acid] poh = pk b + log [weak base] e.g., How much HCl must be added to a liter of buffer that is 1.5 M in acetic acid and 0.75 M in sodium acetate to give a buffer ph of 4.10? (pk a = 1.8 x 10 5 ) Solution: Adding x moles of HCl gives ( x) moles sodium acetate and (1.5 + x) moles acetic acid. Thus

5 ph = pk a + log = (0.75 x) (1.5+x) (0.75 x) (1.5+x) ) x = = log (0.75 x) (1.5+x) Buffer Capacity: how much acid or base can be adsorbed before the buffer is spent. Buffer Range: Buffers are most effective (maximum buffering capacity) when [HA] = [A ]. When [HA] and [A ] differ by more than a factor of 10, the buffer has lost its ability to absorb acid / base. conjugate base ) ph = pk a ± 1 weak acid Preparing a buffer solution with a specific ph: e.g., Prepare a ph = 9.50 buffer using phenol. Solution: We have 9.50 = log [C 6H 5 O ] [C 6 H 5 OH] ) [C 6H 5 O ] [C 6 H 5 OH] = =0.41 We could therefore dissolve 0.41 moles of NaC 6 H 5 O and 1.00 mol of C 6 H 5 OH in 1 L of water.

6 Acid-Base Titrations Titration: reaction of an acid with a base (neutralization) Specifically, the addition of a solution of accurately known concentration (e.g. acid) to a solution of unknown concentration (e.g. base) until the reaction is complete. From the known concentration, the concentration of the other species can be calculated from the stoichiometry. Definitions: o Standard solution: one of known concentration. o Equivalence point: point when stochiometrically equivalent amounts of acid and base are present. o Endpoint: the point in the laboratory when the titration is stopped (often around the equivalence point); typically signaled by the color change of an indicator. o Titrant = the solution that is placed in the buret (typically the one of known concentration) o Titration Curve: ph vs. volume (or moles) of titrant added Types of titration systems that will be considered: o strong acid strong base o weak acid strong base o strong acid weak base Items to keep track of during a titration: o reaction taking place (what is in the beaker) o moles of acid or base in the beaker o moles of base or acid added from the buret o total volume

7 Different places to do a ph calculation in a titration: 1. beginning 2. between the beginning and the equivalence point 3. equivalence point 4. after the equivalence point 5. ½ equivalence point

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22 Acid-base indicator: is a weak organic acid or base for which the ionized and unionized forms (i.e. weak acid and conjugate base, or weak base and conjugate acid) are different colors The ph range over which the indicator changes color depends on the value of its Ka or Kb The color change is used to signal endpoints during a titration. Therefore want this to occur at the steepest part of the titration (need pkindicator to be within ± 1 ph units of equiv. point) The ph at the equivalence point of the titration must be within the ph range where the indicator changes color. Phenolphthalein can be used for both strong acid strong base (blue curve) and for weak acid strong base (red curve). But methyl red is not appropriate for the weak acid strong base case because its color change is not on the steepest part of the curve.

23 Solubility Equilibria

24 Solubility product = K sp Consider the equilibrium between undissolved silver chloride and a saturated silver chloride solution: AgCl(s) Ag + (aq)+cl (aq) Since this is a heterogeneous equilibrium, the equilibrium constant is K sp = [Ag + ][Cl ] o always write the K sp expression with the solid on the left o Molar solubility: moles of solute in 1L of saturated solution o Solubility: grams of solute in 1 L of saturated solution e.g., Calculate the molar solubility and the solubility of PbF 2, given that K sp = 4.0 x 10 8 Solution: PbF 2 (s) Pb F Initial lots 0 0 Change -x +x +2x Equilibrium x 2x This gives K sp = (x)(2x) 2 = 4x 3 x = 2.15 x 10 3 M This is the molar solubility. For the solubility we multiply by the molar mass of (19.00) = to give g/l.

25 e.g., Given that the solubility of Ag 2 SO 3 is 4.6 x 10 3 g/l, what is the solubility product constant K sp? Solution: We first convert to molar solubility: (4.6 x 10 3 g/l) / ( g/mol) = 1.55 x 10 5 M Ag 2 SO 3 2Ag SO 3 Initial lots 0 0 Change -x +2x +x Equilibrium 2x x We know that x = 1.55 x 10 5 M. Thus K sp = 4x 3 = 1.5 x e.g., What is the maximum mass (in grams) of (NH 4 ) 2 SO 4 that can be added to 150 ml of M BaCl 2 without causing a precipitate to form? Solution: First, we have to examine a K sp table (e.g., Table 17.4 in the textbook). We can find that the K sp for BaSO 4 is 1.1 x This means that if [Ba 2+ ][SO 4 2 ] > K sp, we get a precipitate. Since [Ba 2+ ] = M, we can have at most [SO 4 2 ] = K sp /0.050 = 2.2 x 10 9 M. Then we multiply by the volume and the molar mass: (2.2 x 10 9 mol/l) x (0.150 L) x ( g/mol) = 4.4 x 10 8 g

26 Factors Affecting Solubility The common ion effect Consider the solubility of AgCl: AgCl(s) Ag + (aq)+cl (aq) in a solution that already has dissolved AgNO 3 in it. From Le Chatelier s Principle we know that AgCl will be significantly less soluble in 0.10 M AgNO 3 than in pure water. Work out the numbers: Since K sp for AgCl is 1.6 x 10 10, the molar solubility is just the square root of this: 1.3 x Now consider the solubility of AgCl in 0.10 M AgNO 3 AgCl Ag + + Cl Initial lots Change -x +x +x Equilibrium x x K sp = =(x)( x) (x)(0.10) ) x = ph The solubility of a substance can depend on ph. For example, consider Mg(OH) 2 (s) Mg 2+ (aq) + 2OH (aq) At equilibrium, if we add OH ions (increase the ph) the equilibrium will shift to the left, decreasing the solubility of Mg(OH) 2.

27 If we add H + ions (decrease the ph), Mg(OH) 2 will become more soluble. This is why insoluble bases tend to dissolve in acidic solutions. Adding H + results in the reaction 2H OH 2H 2 O(l) which gives the net reaction Mg(OH) 2 (s) + 2H + (aq) Mg 2+ (aq) + 2H 2 O(l) Another example: consider BaF 2 (s) Ba F Since F has acid/base properties, this equilibrium is also affected by ph. Specifically, at low ph, we can write 2H + + 2F 2HF which gives the net reaction BaF 2 (s) + 2H + (aq) Ba 2+ (aq) + 2HF(aq) Separation of Ions using Differences in Solubility Fractional precipitation If we have two or more ions in solution we can separate them by using a compound that can form a precipitate with each of them (with different K sp values). e.g., we can separate Cl (aq) and Br (aq) by using AgNO 3.

28 Silver nitrate is added to a solution containing M Cl and M Br. Calculate the concentration of Ag + ions needed to initiate precipitation of AgBr without precipitating AgCl. Also, when the more soluble species begins to precipitate, what is [Br ]? Solution: AgBr will precipitate first because its K sp is smaller than AgCl. From the expression [Ag + ][Br ] = K sp = 7.7 x We get [Ag + ] = 7.7 x / = 3.9 x M. Any higher value for [Ag + ] will cause AgBr to precipitate. From the expression [Ag + ][Cl ] = K sp = 1.6 x We get [Ag + ] = 1.6 x / = 8.0 x 10 9 M. Any higher value for [Ag + ] will cause AgCl to precipitate. Therefore we can precipitate the maximum amount of AgBr without causing any AgCl to precipitate if we use [Ag + ] = 8.0 x 10 9 M At this point, what is [Br ]? It is 7.7 x / 8.0 x 10 9 = 9.6 x 10 5 M. This is less than 0.5 % of the original [Br ] so we are able to effectively separate Cl and Br (by filtration to remove AgBr).

### CHEM 102: Sample Test 5

CHEM 102: Sample Test 5 CHAPTER 17 1. When H 2 SO 4 is dissolved in water, which species would be found in the water at equilibrium in measurable amounts? a. H 2 SO 4 b. H 3 SO + 4 c. HSO 4 d. SO 2 4 e.

Sample Exercise 17.1 Calculating the ph When a Common Ion is Involved What is the ph of a solution made by adding 0.30 mol of acetic acid and 0.30 mol of sodium acetate to enough water to make 1.0 L of

### Equilibrium Constants The following equilibrium constants will be useful for some of the problems.

1 CH302 Exam 4 Practice Problems (buffers, titrations, Ksp) Equilibrium Constants The following equilibrium constants will be useful for some of the problems. Substance Constant Substance Constant HCO

### AP Chemistry- Acids and Bases General Properties of Acids and Bases. Bases- originally defined as any substance that neutralized an acid

AP Chemistry Acids and Bases General Properties of Acids and Bases Acids Electrolyte Taste Litmus Phenolphthalein React with metals to give off H 2 gas H 2 SO 4 (aq) + Mg (s) MgSO 4 (aq) + H 2 (g) Ionize

### ph: Measurement and Uses

ph: Measurement and Uses One of the most important properties of aqueous solutions is the concentration of hydrogen ion. The concentration of H + (or H 3 O + ) affects the solubility of inorganic and organic

### V. POLYPROTIC ACID IONIZATION. NOTICE: K a1 > K a2 > K a3 EQUILIBRIUM PART 2. A. Polyprotic acids are acids with two or more acidic hydrogens.

EQUILIBRIUM PART 2 V. POLYPROTIC ACID IONIZATION A. Polyprotic acids are acids with two or more acidic hydrogens. monoprotic: HC 2 H 3 O 2, HCN, HNO 2, HNO 3 diprotic: H 2 SO 4, H 2 SO 3, H 2 S triprotic:

### CH302 Exam 4 Practice Problems (buffers, titrations, Ksp)

CH302 Exam 4 Practice Problems (buffers, titrations, Ksp) 1 Equilibrium Constants The following equilibrium constants will be useful for some of the problems. Substance Constant Substance Constant HCO

### Chapter 21 Buffers and the titration of Acids and Bases Shuffle order make 21-3 last!

Chapter 21 Buffers and the titration of Acids and Bases Shuffle order make 213 last! 211 The HendersonHasselbalch Equation What happens when you mix an acid and its own conjugate base? Using an acetic

### Lecture 6. Classes of Chemical Reactions

Lecture 6 Classes of Chemical Reactions Lecture 6 Outline 6.1 The Role of Water as a Solvent 6.2 Precipitation Reactions 6.3 Acid-Base Reactions 1 Electron distribution in molecules of H 2 and H 2 O The

### Name period Unit 9: acid/base equilibrium

Name period Unit 9: acid/base equilibrium 1. What is the difference between the Arrhenius and the BronstedLowry definition of an acid? Arrhenious acids give H + in water BronstedLowry acids are proton

### Acid/Base Definition. Acid/Base Reactions. Major vs. Minor Species. Terms/Items you Need to Know. you need to memorize these!!

Acid/Base Reactions some covalent compounds have weakly bound H atoms and can lose them to water (acids) some compounds produce OH in water solutions when they dissolve (bases) acid/base reaction are very

### General Chemistry II Chapter 20

1 General Chemistry II Chapter 0 Ionic Equilibria: Principle There are many compounds that appear to be insoluble in aqueous solution (nonelectrolytes). That is, when we add a certain compound to water

### Q.1 Classify the following according to Lewis theory and Brønsted-Lowry theory.

Acid-base A4 1 Acid-base theories ACIDS & BASES - IONIC EQUILIBRIA 1. LEWIS acid electron pair acceptor H, AlCl 3 base electron pair donor NH 3, H 2 O, C 2 H 5 OH, OH e.g. H 3 N: -> BF 3 > H 3 N BF 3 see

### Chapter 17. The best buffer choice for ph 7 is NaH 2 PO 4 /Na 2 HPO 4. 19)

Chapter 17 2) a) HCl and CH 3 COOH are both acids. A buffer must have an acid/base conjugate pair. b) NaH 2 PO 4 and Na 2 HPO 4 are an acid/base conjugate pair. They will make an excellent buffer. c) H

### WEAK ACIDS AND BASES

WEAK ACIDS AND BASES [MH5; Chapter 13] Recall that a strong acid or base is one which completely ionizes in water... In contrast a weak acid or base is only partially ionized in aqueous solution... The

### Chemistry 212 EXAM 2 February 17, 2004 KEY

1 Chemistry 212 EXAM 2 February 17, 2004 100_ (of 100) KEY Name Part 1: Multiple Choice. (1 point 4. The equilibrium constant for the each, circle only one answer, reaction 1. For the equilibrium that

### Review for Solving ph Problems:

Review for Solving ph Problems: Acid Ionization: HA H 2 O A - H 3 O CH 3 COOH H 2 O CH 3 COO - H 3 O Base Ionization: B H 2 O BH OH - 1) Strong Acid complete dissociation [H ] is equal to original [HA]

### Common Ion Effects. CH 3 CO 2 (aq) + Na + (aq)

Common Ion Effects If two reactions both involve the same ion, then one reaction can effect the equilibrium position of the other reaction. The ion that appears in both reactions is the common ion. Buffers

### Tutorial 4 SOLUTION STOICHIOMETRY. Solution stoichiometry calculations involve chemical reactions taking place in solution.

T-27 Tutorial 4 SOLUTION STOICHIOMETRY Solution stoichiometry calculations involve chemical reactions taking place in solution. Of the various methods of expressing solution concentration the most convenient

### Titrations. Acid-Base Indicators and Titration Curves. Shapes of Titration Curves. A titration curve is a graphical history of a titration

Acid-Base Indicators and Titration Curves Titrations In a titration a solution of accurately known concentration is added gradually added to another solution of unknown concentration until the chemical

### Solubility Product Constant

Solubility Product Constant Page 1 In general, when ionic compounds dissolve in water, they go into solution as ions. When the solution becomes saturated with ions, that is, unable to hold any more, the

### Experiment # 6 Determining the percent composition of a mixture by acid-base

Experiment # 6 Determining the percent composition of a mixture by acid-base Objective Determine the percent composition of a mixture of sodium carbonate (Na 2 CO 3 ), sodium bicarbonate (NaHCO 3 ) and

### Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry

AP Chemistry A. Allan Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry 4.1 Water, the Common Solvent A. Structure of water 1. Oxygen's electronegativity is high (3.5) and hydrogen's

### A strong acid and the salt of its conjugate base don't make a good buffer. Why? (aq) + OH - (aq)

5.111 Lecture Summary #23 cid/base Equilibrium Continued From Friday s handout Topic: Titrations 23.1 cid buffer action: The weak acid,, transfers protons to O ions supplied by strong base. The conjugate

### Titration curves. Strong Acid-Strong Base Titrations

Titration curves A titration is a procedure for carrying out a chemical reaction between two solutions by the controlled addition from a buret of one solution (the titrant) to the other, allowing measurements

### Problems you need to KNOW to be successful in the upcoming AP Chemistry exam.

Problems you need to KNOW to be successful in the upcoming AP Chemistry exam. Problem 1 The formula and the molecular weight of an unknown hydrocarbon compound are to be determined by elemental analysis

### 2. Write a balanced chemical equation which corresponds to the following equilibrium constant expression. 1/2 3/ 2

Practice Problems for Chem. 1B Exam 1 F2011 These represent the concepts covered for exam 1. There may be some additional net ionic equations from chem. 1A. This is not the exact exam! Sections 16.1-16.3

### Q.1 Classify the following according to Lewis theory and Brønsted-Lowry theory.

Acid-base 2816 1 Acid-base theories ACIDS & BASES - IONIC EQUILIBRIA LEWIS acid electron pair acceptor H +, AlCl 3 base electron pair donor NH 3, H 2 O, C 2 H 5 OH, OH e.g. H 3 N: -> BF 3 > H 3 N + BF

### Practical Lesson No 4 TITRATIONS

Practical Lesson No 4 TITRATIONS Reagents: 1. NaOH standard solution 0.1 mol/l 2. H 2 SO 4 solution of unknown concentration 3. Phenolphthalein 4. Na 2 S 2 O 3 standard solution 0.1 mol/l 5. Starch solution

### Chemical equilibria Buffer solutions

Chemical equilibria Buffer solutions Definition The buffer solutions have the ability to resist changes in ph when smaller amounts of acid or base is added. Importance They are applied in the chemical

### To see how this data can be used, follow the titration of hydrofluoric acid against sodium hydroxide below. HF (aq) + NaOH (aq) H2O (l) + NaF (aq)

Weak Acid Titration v120413 You are encouraged to carefully read the following sections in Tro (2 nd ed.) to prepare for this experiment: Sec 4.8, pp 158-159 (Acid/Base Titrations), Sec 16.4, pp 729-43

### 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436 #1, 7, 8, 11

SCH3U- R.H.KING ACADEMY SOLUTION & ACID/BASE WORKSHEET Name: The importance of water - MAKING CONNECTION READING 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436

### Solubility of Salts - Ksp. Ksp Solubility

Solubility of Salts - Ksp We now focus on another aqueous equilibrium system, slightly soluble salts. These salts have a Solubility Product Constant, K sp. (We saw this in 1B with the sodium tetraborate

### Stoichiometry and Aqueous Reactions (Chapter 4)

Stoichiometry and Aqueous Reactions (Chapter 4) Chemical Equations 1. Balancing Chemical Equations (from Chapter 3) Adjust coefficients to get equal numbers of each kind of element on both sides of arrow.

### EXPERIMENT 12 A SOLUBILITY PRODUCT CONSTANT

PURPOSE: 1. To determine experimentally the molar solubility of potassium acid tartrate in water and in a solution of potassium nitrate. 2. To examine the effect of a common ion on the solubility of slightly

### Note: (H 3 O + = hydronium ion = H + = proton) Example: HS - + H 2 O H 3 O + + S 2-

AcidBase Chemistry Arrhenius acid: Substance that dissolves in water and provides H + ions Arrhenius base: Substance that dissolves in water and provides OH ions Examples: HCl H + and Cl Acid NaOH Na +

### AP*Chemistry Solubility Equilibria

AP*Chemistry Solubility Equilibria SOLUBILITY EQUILIBRIA (K sp, THE SOLUBILITY PRODUCT) Saturated solutions of salts are another type of chemical equilibria. Remember those solubility rules? The fine print

### ) g /mol = 3.86!10"3 moles

Chem01, Winter 006 Midterm N1 01/6/06 Name Answer key SID 1. A solution is prepared by dissolving 5.8 grams on magnesium chloride (MgCl ) in water to produce 50.0 ml of solution. Molecular weight of the

### ph Measurement and its Applications

ph Measurement and its Applications Objectives: To measure the ph of various solutions using ph indicators and meter. To determine the value of K a for an unknown acid. To perform a ph titration (OPTIONAL,

### CHM1 Review for Exam 12

Topics Solutions 1. Arrhenius Acids and bases a. An acid increases the H + concentration in b. A base increases the OH - concentration in 2. Strong acids and bases completely dissociate 3. Weak acids and

### Acid-Base Titrations. Setup for a Typical Titration. Titration 1

Titration 1 Acid-Base Titrations Molarities of acidic and basic solutions can be used to convert back and forth between moles of solutes and volumes of their solutions, but how are the molarities of these

### If we write these equations in ionic form, in each case the net ionic equation is the same; H 3 O + (aq) + OH - (aq) H 2H 2 O(l)

CHEM 1105 ACIDS AND BASES 1. Early Definitions Taste: Effect on Indicators: Neutralization: acids - sour; bases - bitter acids turn blue litmus red; bases turn red litmus blue phenolphthalein is colourless

### Equilibrium, Acids and Bases Unit Summary:

Equilibrium, Acids and Bases Unit Summary: Prerequisite Skills and Knowledge Understand concepts of concentration, solubility, saturation point, pressure, density, viscosity, flow rate, and temperature

### Chemistry 51 Chapter 8 TYPES OF SOLUTIONS. A solution is a homogeneous mixture of two substances: a solute and a solvent.

TYPES OF SOLUTIONS A solution is a homogeneous mixture of two substances: a solute and a solvent. Solute: substance being dissolved; present in lesser amount. Solvent: substance doing the dissolving; present

### Acids, Bases, Salts, and Buffers

Acids, Bases, Salts, and Buffers GOAL AND OVERVIEW Hydrolysis of salts will be used to study the acid-base properties of dissolved ions in aqueous solutions. The approximate ph of these solutions will

### stoichiometry = the numerical relationships between chemical amounts in a reaction.

1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse

### 16. What is the H 3 O + concentration of a solution that has an OH concentration of 1 10 3 M? 1) 1 10 4 M 3) 1 10 11 M

1. If the [OH ] = 1 10 4 at 298 K for a given solution, the [H + ] of the solution is equal to 1) 1 10 14 3) 1 10 6 2) 1 10 10 4) 1 10 4 2. Based on Reference Table V, which is the strongest base? 1) NO

### AP Chemistry Unit 7- Homework Problems Equilibrium and K sp

AP Chemistry Unit 7- Homework Problems Equilibrium and K sp Nature of the Equilibrium State 1. Draw on this graph where equilibrium has been reached. [X] equilibrium time 2. What are three qualities of

### Topic 18 Acids and Bases. 18.1 Exercises

Topic 18 Acids and Bases 18.1 Exercises 1. Define: (a) ph The negative log of the hydrogen ion concentration in a solution. i.e. ph = log[h 3 O + ] (b) poh The negative log of hydroxide ion concentration

### Acids and Bases. Chapter 16

Acids and Bases Chapter 16 The Arrhenius Model An acid is any substance that produces hydrogen ions, H +, in an aqueous solution. Example: when hydrogen chloride gas is dissolved in water, the following

### Chapter 7 Mixtures of Acids and Bases

Chapter 7 Mixtures of Acids and Bases Introduction In Chapter 6, we examined the equilibrium concentrations in solutions of acids and solutions of bases. In this chapter, we continue our discussion of

### Chemistry 132 NT. Solubility Equilibria. The most difficult thing to understand is the income tax. Solubility and Complex-ion Equilibria

Chemistry 13 NT The most difficult thing to understand is the income tax. Albert Einstein 1 Chem 13 NT Solubility and Complex-ion Equilibria Module 1 Solubility Equilibria The Solubility Product Constant

### Chemistry. Zumdahl, 7th edition

Chemistry Zumdahl, 7th edition CH4 Types of Chemical Reactions and Solution Stoichiometry Yellow lead(ii) iodide is produced when lead(ii) nitrate is mixed with potassium iodide. P.126 Contents 4.1 Water,

### Acids and Bases. When an acid loses a proton, the resulting species is its conjugate base. For example, NH 3 + H +

Acids and Bases Definitions An acid is a proton donor, e.g. HCl. For example, consider the reaction between HCl and H 2 O. HCl + H 2 O H 3 O + + Cl - Acid In this reaction, HCl donates a proton to H 2

### CHEM 12 Acids and Bases 3/22/2016

Acids and Bases Name: Expected background knowledge from acids and bases introductory reading: Definitions (Arrhenius, BL) of an acid and base Definitions of conjugate acid and base pairs Properties of

### Since we will be dealing with aqueous acid and base solution, first we must examine the behavior of water.

Acids and Bases Know the definition of Arrhenius, Bronsted-Lowry, and Lewis acid and base. Autoionization of Water Since we will be dealing with aqueous acid and base solution, first we must examine the

### Today. How to solve all acid/base problems (except the ones we ll do next week) Strong Acid Weak Acid Buffer Weak Base Strong Base

Today How to solve all acid/base problems (except the ones we ll do next week) Strong Acid Weak Acid Buffer Weak Base Strong Base If you re having trouble go step by step 1. Remove the spectator ions (Na

### Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent

Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Water a polar solvent: dissolves most ionic compounds as well as many molecular compounds Aqueous solution:

### 17B. An Acid Base Titration Curve

17B. An Acid Base Titration Curve Time: 2 hours Required chemicals and solutions: Reagent Requirement/5 Pairs Preparation of 1 L Potassium hydrogen phthalate 5.1 g NaOH, 0.1 M 250 ml 4.0 g of NaOH Other

### Titration Curve of a Weak Acid

Titration Curve of a Weak Acid Amina Khalifa El-Ashmawy, Ph.D. Collin College Department of Chemistry Introduction: Titration is an analytical process whereby two reactant solutions are carefully reacted

### 7 Investigation of Buffer Systems

7 Investigation of Buffer Systems Name: Date: Section: Objectives Reinforce concepts of buffer, buffer range and buffer capacity Learn how to prepare acid-base buffers Learn how to calculate the of a buffer

### Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions.

Aqueous Solutions and Solution Stoichiometry Water is the dissolving medium, or solvent. Some Properties of Water Water is bent or V-shaped. The O-H bonds are covalent. Water is a polar molecule. Hydration

### Answer Key, Problem Set 5 (With explanations)--complete

Chemistry 122 Mines, Spring 2016 Answer Key, Problem Set 5 (With explanations)complete 1. NT1; 2. NT2; 3. MP; 4. MP (15.38); 5. MP (15.40); 6. MP (15.42); 7. NT3; 8. NT4; 9. MP; 10. NT5; 11. NT6; 12. MP;

### Auto-ionization of Water

2H 2 O H 3 O + + OH Hydronium ion hydroxide ion Q: But how often does this happen? This is the fundamental concept of all acid-base chemistry In pure water, how much of it is water and how much is ions?

### 1. Identify the Bronsted-Lowry acids and bases and the conjugate acid base pairs in the following reactions.

Exercise #1 Brønsted-Lowry s and Bases 1. Identify the Bronsted-Lowry acids and bases and the conjugate acid base pairs in the following reactions. (a) HCl(aq) + H 2 O(l) H 3 O + (aq) + Cl (aq) (b) H 2

### 1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) 3 (s) + H 2 (g)

1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) A) 1 B) 2 C) 4 D) 5 E) Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) Al (s) + H 2 O (l)? Al(OH)

### AP FREE RESPONSE QUESTIONS ACIDS/BASES

AP FREE RESPONSE QUESTIONS ACIDS/BASES 199 D A chemical reaction occurs when 100. milliliters of 0.200molar HCl is added dropwise to 100. milliliters of 0.100molar Na 3 P0 solution. (a) Write the two net

### SECTION 14 CHEMICAL EQUILIBRIUM

1-1 SECTION 1 CHEMICAL EQUILIBRIUM Many chemical reactions do not go to completion. That is to say when the reactants are mixed and the chemical reaction proceeds it only goes to a certain extent, and

### ACID-BASE TITRATIONS

ACID-BASE TITRATIONS 1 In this exercise you will use Excel to construct titration curves for a titration between a strong acid and strong base and between a weak acid and strong base. To set up a spreadsheet

### 3 The Preparation of Buffers at Desired ph

3 The Preparation of Buffers at Desired ph Objectives: To become familiar with operating a ph meter, and to learn how to use the Henderson-Hasselbalch equation to make buffer solutions at a desired ph

### 1. For the equilibrium that exists in an aqueous solution of nitrous acid (HNO 2, a weak acid), the equilibrium constant expression is:

1. For the equilibrium that exists in an aqueous solution of nitrous acid (HNO 2, a weak acid), the equilibrium constant expression is: a) K = [H+ ][NO 2 ] [HNO 2 ] b) K = [H+ ][N][O] 2 [HNO 2 ] c) K =

### 2001 AP CHEMISTRY FREE-RESPONSE QUESTIONS

2001 AP CHEMISTRY FREE-RESPONSE QUESTIONS CHEMISTRY Section II (Total time 90 minutes) Part A Time 40 minutes YOU MAY USE YOUR CALCULATOR FOR PART A. CLEARLY SHOW THE METHOD USED AND THE STEPS INVOLVED

### ph. Weak acids. A. Introduction

ph. Weak acids. A. Introduction... 1 B. Weak acids: overview... 1 C. Weak acids: an example; finding K a... 2 D. Given K a, calculate ph... 3 E. A variety of weak acids... 5 F. So where do strong acids

### PART I: EQUILIBRIUM. 3. Explain why the tetraamminecopper(ii) solution appears blue.

Part A: Formation of a Complex Ion PART I: EQUILIBRIUM Anhydrous copper(ii) sulfate is white, whereas hydrated copper(ii) sulfate is blue. The structure of the hydrated compound is more accurately represented

### CHAPTER 4. AQUEOUS REACTION CHEMISTRY

CAPTER. AQUEOUS REACTION CEMISTRY solution - homogeneous mixture of or more substances; uniform distribution of particles and same properties throughout. A solution is composed of a solute dissolved in

### An acid is a substance that produces H + (H 3 O + ) Ions in aqueous solution. A base is a substance that produces OH - ions in aqueous solution.

Chapter 8 Acids and Bases Definitions Arrhenius definitions: An acid is a substance that produces H + (H 3 O + ) Ions in aqueous solution. A base is a substance that produces OH - ions in aqueous solution.

### Solutions CHAPTER Specific answers depend on student choices.

CHAPTER 15 1. Specific answers depend on student choices.. A heterogeneous mixture does not have a uniform composition: the composition varies in different places within the mixture. Examples of non homogeneous

### Acids and Bases. Basic Definitions & Concepts

Acids and Bases CHEM 102! T. Hughbanks! Basic Definitions & Concepts Most basic concepts are given clearly in your text - these notes will only list these as topics discussed, so there will be less detail.!

### Similarities The ph of each of these solutions is the same; that is, the [H + ] is the same in both beakers (go ahead and count).

Compare 1 L of acetate buffer solution (0.50 mol of acetic acid and 0.50 mol sodium acetate) to 1 L of HCl solution AcO - AcO - H+ Cl - AcO - AcO - Cl - Cl - AcO - Cl - Cl - Cl - Cl - AcO - AcO - AcO -

### Experiment 6 Titration II Acid Dissociation Constant

6-1 Experiment 6 Titration II Acid Dissociation Constant Introduction: An acid/base titration can be monitored with an indicator or with a ph meter. In either case, the goal is to determine the equivalence

### AMHS AP Chemistry Multiple Choice questions

1 Aqueous Equilibria: Buffers & Titrations AMHS AP Chemistry Multiple Choice questions Name Common-Ion Effect 1) The ph of a solution that contains 0.818 M acetic acid (K a = 1.77x10-5 ) and 0.172 M sodium

### Properties of Aqueous Solutions of Acids and Bases. CHAPTER 10 Acids, Bases and Salts. Properties of Aqueous Solutions of Acids and Bases

CAPTER Acids, Bases and Salts Properties of Aqueous Solutions of Acids and Bases Strong and Weak Acids Acids are substances that generate in aqueous solutions. Strong acids ionize 0% in water. That is,

### Worksheet 23 Strong Acid/Strong Base Titrations

Worksheet 2 Strong Acid/Strong Base Titrations A. Initial ph This is always determined based solely on the initial concentration of the acid or base being titrated. Every mole of acid or base will produce

### Chapter 17. How are acids different from bases? Acid Physical properties. Base. Explaining the difference in properties of acids and bases

Chapter 17 Acids and Bases How are acids different from bases? Acid Physical properties Base Physical properties Tastes sour Tastes bitter Feels slippery or slimy Chemical properties Chemical properties

### Lab #11: Determination of a Chemical Equilibrium Constant

Lab #11: 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

Additional Lecture: TITRATION BASICS 1 Definition and Applications Titration is the incremental addition of a reagent solution (called titrant) to the analyte until the reaction is complete Common applications:

### Chapter 13 EDTA titrations

Chapter 13 EDTA titrations Problems 1-6, 8, 13, 16, 18, 19, 20 Overhead of EDTA Overhead of table 13-1 12-1 Metal Chelate Complexes We are now going to talk about Metal Complexes. These are compounds in

### Chapter 16: Acid-Base Equilibria

Chapter 16: Acid-Base Equilibria In the 1 st half of this chapter we will focus on the equilibria that exist in aqueous solutions containing: weak acids polyprotic acids weak bases salts use equilibrium

### Pharmaceutical Analysis

Pharmaceutical Analysis 62 Pharmaceutical Analysis Definition: Chemical Analysis is a method for determining the substance, its amount or impurity and plays a vital role in the pharmacy. Analytical chemistry

### CHAPTERS 15 FAKE TEST QUESTIONS. 1. According to the Brønsted Lowry definition, which species can function both as an acid and as a base?

You might need to know the following K values: CHAPTERS 15 FAKE TEST QUESTIONS CH 3 COOH K a = 1.8 x 10 5 Benzoic Acid K a = 6.5 x 10 5 HNO 2 K a = 4.5 x 10 4 NH 3 K b = 1.8 x 10 5 HF K a = 7.2 x 10 4

### Electrical Conductivity of Aqueous Solutions

Electrical Conductivity of Aqueous Solutions PRE-LAB ASSIGNMENT: Reading: Chapter 4.-4.3 in Brown, LeMay, Bursten & Murphy.. Using Table in this handout, determine which solution has a higher conductivity,.

### 4C-6 ph of a solution containing 0.75 M lactic acid and 0.25 M sodium lactate. Use the buffer formula: + ] and [OH ] <<.25 and.75.

Chem 220 Buffer Problems Exploration C You should memorize the buffer formulas. They look like the K a definition but have added restrictions. K a = [H +]M NaA M HA K a = [H +]M B M BHCl if [H + ] and

### ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND

#3. Acid - Base Titrations 27 EXPERIMENT 3. ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND Carbonate Equilibria In this experiment a solution of hydrochloric

### Solubility Product. Application of Equilibrium concepts

Solubility Product Application of Equilibrium concepts Introduction In even the most insoluble compounds, a few ions at the least dissolve. We can treat dissolving as a mini reaction in which the cation(s)

### Name: Class: Date: 2 4 (aq)

Name: Class: Date: Unit 4 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The balanced molecular equation for complete neutralization of

### Chemistry Ch 15 (Solutions) Study Guide Introduction

Chemistry Ch 15 (Solutions) Study Guide Introduction Name: Note: a word marked (?) is a vocabulary word you should know the meaning of. A homogeneous (?) mixture, or, is a mixture in which the individual

### UNIT (6) ACIDS AND BASES

UNIT (6) ACIDS AND BASES 6.1 Arrhenius Definition of Acids and Bases Definitions for acids and bases were proposed by the Swedish chemist Savante Arrhenius in 1884. Acids were defined as compounds that