Chemistry 12

Q: Acids, Bases, and Salts (Buffer Solutions)

Q1. describe the tendency of buffer solutions to resist changes in pH
Q2. describe the composition of an acidic buffer and a basic buffer
Q3. outline a procedure to prepare a buffer solution
Q4. identify the limitations in buffering action
Q5. describe qualitatively how the buffer equilibrium shifts as small quantities of acid or base are

added to the buffer
Q6. describe common buffer systems present in industrial, environmental, or biological systems

R: Acids, Bases, and Salts (Acid Rain)

R1. write equations representing the formation of acidic solutions or basic solutions from non-metal

and metal oxides
R2. describe the pH conditions required for rain to be called acid rain
R3. relate the pH of normal rain water to the presence of dissolved CO₂
R4. describe sources of No_xand SO_x
R5. discuss general environmental problems associated with acid rain

Chemistry 12

Lesson Plan - Unit 5

Period #1 - Acids and Bases - Introduction

Materials : Textbook : Hebden

Solubility Exam

Lab 19C Worksheet

Hand-out on Common Acids and Bases

Review : Properties of Acids and Bases from Grade 10 Science

Objectives : students should be able to :

G: to I: Solubility (Meet All Objectives in Unit Four).

J: Acids, Bases, and Salts (Properties and Definitions)

J1. identify acids and bases through experimentation

J2. list general properties of acids and bases

J3. write balanced equations representing the neutralization of acids by bases in solution

J4. define Arrhenius acids and bases

J5. write names and formulae of some common acids and bases and outline some of their common properties, uses, and commercial names

Part I - Test on Solubility - Unit Test :

Students write exam on Solubility Unit.

Students hand in Assignment on Solubility.

Reminder that Lab is due next class.

Evaluation :

Unit Four Exam

Lab 19C

Part II - Introduction to Acids and bases - Arrhenius Acids and Bases :

Do Lab Experiment 20 A - "Introduction to Acids and Bases", and fill out Worksheet. (J1)

Give notes on Arrhenius Theory of Acids and Bases, page 5-1 . (J4)

Review Neutralization Reactions between acids and bases, and give examples on page 5-2. (J3)

List general properties of acids and bases on page 5-3. (J2)

Give hand-out of common acids and bases and go over it briefly. Students are responsible for becoming familiar with the names and formulae of some common acids and bases and outlining some of their common properties, uses, and commercial names (J5)

Exercise :

Question 1 page 110 of Hebden.

Question 2 page 110 of Hebden every other letter.

Questions 3-4 page 112 of Hebden.

Questions 5-9 page 114 of Hebden.

Question 10 on page 115 of Hebden

Evaluation :

Unit Five Exams A and B

Unit Five Hand-in Assignments A and B

Lab 19C Worksheet

Homework

Chemistry 12

Lesson Plan - Unit 5

Period #2 - Acids and Bases - Bronsted / Lowry

Materials : Textbook : Hebden

Review : Arrhenius Definition of Acids and Bases, homework questions.

Objectives : students should be able to :

J: Acids, Bases, and Salts (Properties and Definitions)

J6. define Brönsted-Lowry acids and bases

J7. identify Brönsted-Lowry acids and bases in an equation

J8. write balanced equations representing the reaction of acids or bases with water

J9. identify an H₃0⁺ ion as a protonated H₂0 molecule that can be represented as H⁺_(aq)

J10. define conjugate acid-base pair

J11. identify the conjugate of a given acid or base

J12. show that in any Brönsted-Lowry acid-base equation there are two conjugate pairs present

K: Acids, Bases, and Salts (Strong and Weak Acids and Bases)

K1. relate electrical conductivity in a solution to the concentration of ions

K2. classify an acid or base in solution as either weak or strong by comparing conductivity

K3. define a strong acid and a strong base

K4. define a weak acid and a weak base

K5. write equations to show what happens when strong and weak acids and bases are dissolved in water (dissociation, ionization)

K6. compare the relative strengths of acids or bases by using a table of relative acid strengths

K7. identify and explain why the strongest acid in aqueous solutions is H₃0⁺ and the strongest base in aqueous solutions is OH^-

K9. compare the relative concentrations of H₃0+ (or OH-) between two acids (or between two bases) using their relative positions on an acid strength table

K10. define amphiprotic

K11. identify chemical species that are amphiprotic

K12. describe situations in which H₂0 would act as an acid or base

Part I - Bronsted - Lowry Definitions - New Definition of Acids and Bases :

Discuss the true nature of the H⁺ ion and how it attaches to a water molecule to form a hydronium ion, give notes on page 5-4, and examples of using H⁺ or H₃O⁺ in equations. (J9)

Introduce the Bronsted-Lowry Theory of acids and bases, give notes on the definitions from page 5-5 (J6)

Go through examples on page 5-5 and write balanced equations representing the reaction of acids or bases with water and identify which species acts as the acid and which species act as the base. (J8)(J7)(K12)

Define and give examples of species that are amphiprotic (page 5-6 of notes).(K10)(K11)(K12)

Define : monoprotic, diprotic, triprotic and polyprotic (page 5-6 of notes).

Exercise :

Question 10 page 115 of Hebden.

Questions 11-12 page 117 of Hebden.

Questions 13-14 page 119 of Hebden.

Part II - Bronsted-Lowry - Conjugate Acid and Base Pairs :

Define Conjugate Acid-Base pairs. Give notes on page 5-6. (J10)

Practice identifying Conjugate Acid and Conjugate Base in acid base reactions (J11) and show that in any Brönsted-Lowry acid-base equation there are two conjugate pairs present. (J12)

Exercise :

Questions 16-19 page 121 of Hebden.

Part III - Strong and Weak Acids and Bases - Table of relative acid strengths

Demonstrate that electrical conductivity in a solution is relative to the concentration of ions using a conductivity apparatus. (K1) And classify an acid or base in solution as either weak or strong by comparing conductivity of a number of samples using the apparatus. (K2)

Define a strong acid and a strong base as 100% ionized in water (notes page 5-8). (K3)

Define a weak acid and a weak base as less that 100% ionized in water (notes page 5-9) , (K4) and compare the relative strengths of acids or bases by using a table of relative acid strengths (K6) and compare the relative concentrations of H₃0+ (or OH-) between two acids (or between two bases) using their relative positions on an acid strength table (K9)

Do examples and write equations to show what happens when strong and weak acids and bases are dissolved in water (dissociation, ionization) on page 5-10.(K5).

Use the table to identify and explain why the strongest acid in aqueous solutions is H₃0⁺ and the strongest base in aqueous solutions is OH^- , give notes on the "levelling Effect", page 5-11 (K7)

Exercise :

Questions 21-27 page 125-6 of Hebden.

Evaluation :

Unit Five Exams A and B

Unit Five Hand-in Assignments A and B

Homework

Chemistry 12

Lesson Plan - Unit 5

Period #3 - Acids and Bases - Kw

Materials : Textbook : Hebden

Acid Base Hand-in Assignment A

Marked Solubility Exam

Review : Bronsted-Lowry Definition of Acids and Bases, weak acids and weak bases vs strong acids and strong bases, homework questions.

Objectives : students should be able to :

L: Acids, Bases, and Salts (K_w , pH, pOH)

L1. write equations representing the ionization of water using either H₃0⁺ and OH^- or H⁺ and OH^-

L2. write the equilibrium expression for the ion product constant of water, K_w

L3. predict the effect of the addition of an acid or base to the equilibrium system:

2H₂O₍₁₎ D H₃0⁺_(aq)+OH^-_(aq)

L4. state the relative concentrations of H₃0⁺ and OH^- in acid, base, and neutral solutions

L5. state the value of K_w at 25°C

L6. describe the variation of the value of K_w with temperature

L7. calculate the concentration of H₃0⁺ (or OH^-) given the other, using K_w

Part I - Go Over Solubility Exam - Corrections :

Go over Solubility Exam and have students do the corrections for homework.

Part II - Acids, Bases, and Salts - Introduction to K_w :

Give notes on page 5-12 on the relative concentrations of H₃0⁺ and OH^- in acid, base, and neutral solutions (L4), and the equations representing the ionization of water using either H₃0⁺ and OH^- or H⁺ and OH^- (L1) .

Use the equation for the self ionization reaction of water to determine the equilibrium expression for the ion product constant of water, K_w (L2).

Once the K_w expression is determined predict the effect of the addition of an acid or base to the equilibrium system 2H₂O₍₁₎ D H₃0⁺_(aq)+OH^-_(aq)using Le Chatelier's Principal (L3) see page 5-12 notes.

Stress that the value of K_w at 25°C is 1.00 x 10^-14, (L5) and that the K_w will vary with temperature according to Le Chatelier's Principal (L6).

Do examples and practice questions on page 5-13 to calculate the concentration of H₃0⁺ (or OH^-) given the other, using K_w(L7).

Exercise :

Questions 28-30 page 127 of Hebden.

Hand in Assignment for Acids and Bases Part A

Evaluation :

Unit Five Exams A and B

Unit Five Hand-in Assignments A and B

Homework

Chemistry 12

Lesson Plan - Unit 5

Period #4 - Acids and Bases - Ka, Kb

Materials : Textbook : Hebden

Review : Hand in corrections from Solubility Exam. K_w expression, homework questions.

Objectives : students should be able to :

M: Acids, Bases, and Salts (Ka and Kb Problem Solving)

M1. write Ka and Kb equilibrium expressions

M2. relate the magnitude of Ka or Kb to the strength of the acid or base

M4. calculate the value of Kb for a base given the value of Ka for its conjugate acid (or vice versa)

K8. predict whether products or reactants are favoured in an acid-base equilibrium by comparing the strength of the two acids (or two bases)

Define and familiarize calculator functions for : Log, Antilog, pH, and pOH

L: Acids, Bases, and Salts (K_w , pH, pOH)

L11. perform calculations relating pH, pOH, H₃0+, and OH-

Part I - Ka and Kb Problem Solving - Relating To K_eq :

Give notes and examples on page 5-14 on writing Ka and Kb equilibrium expressions (M1) and relate the magnitude of Ka or Kb to the strength of the acid or base (M2).

Discuss the relationship between Ka and Kb for a conjugate pair (Ka x Kb = Kw), give notes on page 5-15 and practice calculating the value of Kb for a given base when given the value of Ka for its conjugate acid, or vice versa (M4).

Determine that Ka and Kb are just 'different names' for Keq expressions, and recall how to predict whether products or reactants are favoured in an equilibrium and apply the method to acid-base equilibrium by comparing the strength of the two acids, or two bases (K8).

Give notes and examples on "The Relative Strengths of Acids and Bases", on page 5-16 and 5-17 and explain how the side with the stronger acid will be more likely to donate a proton, thereby pushing the equilibrium towards the side with the weaker acid. See cartoon on page 132.

Exercise :

Questions 35-37 page 130 of Hebden.

Questions 38-46 page 133 of Hebden

Part II - Introduction to Logs and Antilogs - pH and pOH :

Give notes and examples on page 18, "Logs and Antilogs", define and familiarize calculator functions for : Log, Antilog, pH, and pOH.

Discuss the proper method for determining significant digits - only the digits after the decimal are significant digits in a pH or pOH.

Practice performing calculations relating pH, pOH, H₃0+, and OH- (L11).

Exercise :

Questions 47-48 page 135 of Hebden.

Questions 49-50 page 139 of Hebden.

Evaluation :

Unit Five Exams A and B

Unit Five Hand-in Assignments A and B

Homework

Chemistry 12

Lesson Plan - Unit 5

Period #5 - Acids and Bases - pH, pOH

Materials : Textbook : Hebden

pH Scale

Review : K_a, K_b, logs, antilogs, pH, pOH and homework questions.

Objectives : students should be able to :

L: Acids, Bases, and Salts (K_w , pH, pOH)

L8. describe the pH scale with reference to everyday solutions
L9. define pH and pOH

L10. define pKw , give its value at 25°C, and its relation to pH and pOH

L11. perform calculations relating pH, pOH, H₃0+, and OH-

L12. calculate H₃0⁺ or OH^- from pH and pOH

Review All Learning Outcomes from J1 - L12.

Part I - Acids, Bases, and Salts (K_w , pH, pOH) - pH Calculations :

Recall the definitions of pH and pOH (L8).

Give notes and examples (L11, L12) on the derivation of pH + pOH = 14, page 5-20 and define pKw , giving its value at 25°C, and its relation to pH and pOH (L10).

Hand out and describe the pH scale with reference to everyday solutions. Give notes on the pH Scale from page 5-21 (L8).

Calculate H₃0+ or OH- from pH and pOH when mixing strong acids and bases, give notes and examples on page 5-23 and 5-24, and do questions in Hebden.

Exercise :

Questions 51-51 pages 139-140 of Hebden.

Questions 55-57 page 141 of Hebden.

Questions 58-68 pages 143 - 144 of Hebden.

Part II - Acids and Bases Unit Part A - Review :

Review all learning outcomes from J1 to L12, and prepare for Acid Base Unit Test Part A.

Exercise :

Selected questions from Hebden.

Evaluation :

Unit Five Exams A and B

Unit Five Hand-in Assignments A and B

Homework

Chemistry 12

Lesson Plan - Unit 5

Period #6 - Acids and Bases - Part A Test, Hydrolysis

Materials : Textbook : Hebden

Objectives : students should be able to :

Meet all Learning Outcomes from J1 - L12

N: Acids, Bases, and Salts (Hydrolysis of Salts)

N1. write a dissociation equation for a salt in water
N2. write net ionic equations representing the hydrolysis of salts
N3. predict qualitatively whether a salt solution would be acidic, basic, or neutral
N4. determine whether an amphiprotic ion will act as a base or an acid in solution

M: Acids, Bases, and Salts (Ka and Kb Problem Solving)

M3. given the Ka, Kb, and initial concentration, calculate any of the following: