Section I: Daily Calendar of Lessons



SC5 – Quantitative Analysis Calendar of Lessons

Section I - Daily Calendar of Lessons

|Aim # |Instructional Objectives |Performance Standards |Suggested Resources |References to Regents Exams |

| | | | | |

| | | | |Homework |

|Aim – How can we perform calculations |Perform calculations involving | |Textbook and lab manual. |1. Read pages 37-43 in text;  Do page|

|involving significant figures? |significant figures. | | |52 #3-1, 3-2, 3-3, 3-4, 3-5. |

|One Day Aim |Understand the difference between | | | |

| |accuracy and precision. | | | |

|Lab Aim – What rules do we need to |Understand the rules to operate safely| |Textbook and lab manual. |2. Read pages 1-2 in the lab manual. |

|learn about lab safety? |in the laboratory. | | | |

|One Day Aim |Identify equipment used in the | | | |

| |quantitative laboratory and understand| | | |

| |their proper use. | | | |

|Aim – What are some stoichiometrical |Perform a variety of calculations | |Textbook and lab manual. |3. Answer SQ (supplemental questions)|

|calculations that are made in |involving moles, grams, molecules, | | |1-3 (see attached sheet) |

|Quantitative Analysis? |volume, and concentration (incl. | | | |

|One Day Aim |Normality). | | | |

| |Balance equations used in quantitative| | | |

| |analysis. | | | |

|Lab Aim – How can we use and read |Use analytical balances. | |Textbook and lab manual. |4. Read pages 22-31 in text; on page |

|equipment to take measurements for our|Use and read the Buret. | | |35 answer #2-2, 2-4 |

|first experiment? |Perform a titration. | | | |

|One Day Aim | | | | |

|Lab Aim - How can we standardize a |Standardize a solution by performing a| |Textbook and lab manual. |5. Read pages 3-8 in lab manual |

|solution of potassium dichromate? |titration of pure FAS. | | | |

|Three Day Aim |Calculate the normality of the | | | |

| |standardized solution. | | | |

|Lab Aim – How can determine the purity|Use a standardized solution to | |Textbook and lab manual. |6. Read pgs 3-8 in lab manual. |

|of iron in a sample of FAS? |calculate the purity of an unknown | | | |

|Three Day Aim |sample. | | | |

|Aim - What are some basic concepts |Review the definitions and properties | |Textbook and lab manual. |7. Read pages 81-90 in text; on page |

|involving ionic equilibria? |of acids and bases. | | |92 answer questions 5-12, 5-13. |

|One Day Aim |Identify the different types of | | | |

| |electrolytes. | | | |

| |Derive net ionic equations. | | | |

|Aim – What are the properties of |Define and solve for ka and pka, kb, | |Textbook and lab manual. |8. Page 92 answer questions 5-14, |

|simple weak acids and bases and their |and pkb. | | |5-15, 5-16. |

|salts? |Determine the ka and kb of a salt. | | | |

|Three Day Aim | | | | |

|Aim – What are the different equations|Use derive the Henderson Hasselbach | |Textbook and lab manual. |9. Answer SQ 4,5. |

|that are used to solve for pH? |equation. | | | |

|Two Day Aim |Solve problems using HH equation. | | | |

|Aim – How can we draw alpha diagrams? |Draw an alpha diagrams from data given| |Textbook and lab manual. |10. Read pgs 171-173; on page 180 |

|One Day Aim |about pH and pka. | | |#10-6. |

| |Use alpha diagrams to Determine the | | | |

| |fractional composition to help solve | | | |

| |HH. | | | |

|Aim – How can we prepare a buffer? |Define buffer and identify the | |Textbook and lab manual. |11. Read 166- 170; page 180 #10-2, |

|One Day Aim |properties of a buffer. | | |10-5. |

| |Prepare a buffer. | | | |

|Aim – How can we solve buffer problems|Calculate pH using ka and | |Textbook and lab manual. |12. Page 180 #10-3, 10-4. |

|involving weak acids? |Henderson-Hasselbalch equation. | | | |

|Two Day Aim | | | | |

|Aim – How can we solve buffer problems|Calculate pH using kb and | |Textbook and lab manual. |13. Read pages 13-34 in lab manual. |

|involving weak bases? |Henderson-Hasselbalch equation. | | | |

|Two Day Aim | | | | |

|Lab Aim – How can we prepare and |Prepare 0.1M solutions. | |Textbook and lab manual. |14. Read 173-177; page 180 #10-11, |

|standardize solutions of HCl and NaOH?|Determine the acid / base volume | | |10-13, 10-18. |

|Five Day Aim |ratio. | | | |

| |Standardize the NaOH with pure KHP. | | | |

| |Standardize the HCl with pure Na2CO3. | | | |

| |Determine the internal consistency of | | | |

| |normality. | | | |

|Aim – How can one correctly determine |Calculate how much of a salt should be| |Textbook and lab manual. |15. SQ 6-7. |

|buffer capacity? |used to form a buffer. | | | |

|Two Day Aim |Calculate the pH range of the buffer. | | | |

| |Determine a proper indicator for the | | | |

| |buffer. | | | |

|Aim – What are the steps in |Calculate the pH in a hydrolysis | |Textbook and lab manual. |16. Read 35-36 in lab manual. |

|calculating the pH in a hydrolysis |reaction. | | | |

|reaction? |Predict the products of a hydrolysis | | | |

|Two Day Aim |reaction. | | | |

| | | | | |

| | | | | |

|Lab Aim – How can one determine the |Determine the percent purity of KHP. | |Textbook and lab manual. |17. Read 36-37 in lab manual. |

|percent purity of KHP in an unknown |Calculate percent purity based upon | | | |

|sample? |experimentation. | | | |

|Three Day Aim | | | | |

|Lab Aim – How can one determine the |Determine the percent purity of soda | |Textbook and lab manual. |18. Read 207-208; SQ 8,9. |

|percent purity of Soda Ash in an |ash. | | | |

|unknown sample? |Calculate percent purity based upon | | | |

|Three Day Aim |experimentation. | | | |

|Aim – What are the properties of |Differentiate between di-, tri- and | |Textbook and lab manual. |19. SQ 10-12. |

|polyprotic acids? |tetraprotic acids. | | | |

|One Day Aim |Write dissociation reactions for | | | |

| |polyprotic acids. | | | |

|Aim – How can one prepare a polyprotic|Draw an alpha diagram for polyprotic | |Textbook and lab manual. |20. Read 183-192;  page 204 # 11-1, |

|acid buffer? |acids. | | |11-2, 11-6, 11-16. |

|One Day Aim |Identify the proper ka value to | | | |

| |accompany each ionic species. | | | |

|Aim – How does one solve calculations |Calculate pH of a polyprotic acid | |Textbook and lab manual. |21. Read 218-221; SQ 13-14. |

|involving triprotic acids? |using proper ka or | | | |

|Three Day Aim |Henderson-Hasselbalch. | | | |

| | | | | |

|Aim - How can we solve buffer problems|Calculate pH of a polyprotic acid | |Textbook and lab manual. |22. Read 133-136; pg 144 # 8-1, 8-2. |

|involving polyprotic acids? |buffer using proper ka or | | | |

|Three Day Aim |Henderson-Hasselbalch. | | | |

| |Determine the proper amount of buffer | | | |

| |salt needed to make a buffer solution.| | | |

|Aim – How can we determine the pH at |Calculate the pH at various points on | |Textbook and lab manual. |23. SQ 13,14. |

|various stages of an acid/base |the titration curve. | | | |

|titration? |Determine the equivalent point and the| | | |

|Three Day Aim |end point. | | | |

| |Determine the titration error. | | | |

|Aim – How can we determine the pH at |Calculate the pH at various points on | |Textbook and lab manual. |24. Read 137-138. |

|various stages of a polyprotic |the polyprotic titration curve. | | | |

|acid/base titration? |Determine the two equivalence points. | | | |

|Three Day Aim | | | | |

|Aim – What can Beer’s Law tell us |Determine the relationship between | |Textbook and lab manual. |25. Read 350-360; pg 365 # 19-1, 19-2,|

|about a solution? |absorbance and transmittance. | | |19-4. |

|Two Day Aim |Use Beer’s Law to calculate | | | |

| |absorbance. | | | |

|Aim – What can Bouguer’s Law tell us |Use Bouguer’s Law to calculate | |Textbook and lab manual. |SQ 15 and 16. |

|about a solution? |absorbance. | | | |

|One Day Aim |Combine Bouguer’s and Beer’s Laws to | | | |

| |determine the relationship between | | | |

| |absorbance and concentration. | | | |

|Aim – Of what use is the |Learn how a spectrophotometer works. | |Textbook and lab manual. |SQ 17 and 18. |

|spectrophotometer in quantitative |Capabilities and limitations of the | | | |

|analysis? |spectrophotometer. | | | |

|One Day Aim | | | | |

| | | | | |

| | | | | |

| | | | | |

| | | | | |

|Aim – How can we complete calculations|Calculate percent purity in unknown | |Textbook and lab manual. | |

|in gravimetric analysis? |samples. | | | |

|Two Day Aim |Calculate how much precipitating | | | |

| |reagent is needed. | | | |

|Lab Aim – How can we gravimetrically |Determine the percent Cl in an unknown| |Textbook and lab manual. |26. Read 39-46 in lab manual. |

|determine the percent purity of |sample. | | | |

|chloride in an unknown sample? |Properly use fritted crucibles. | | | |

|Four Day Aim |Calculate the volume of dissolving | | | |

| |solution needed. | | | |

| |Test for the completeness of | | | |

| |precipitation. | | | |

|Lab Aim – How can we titrimetrically |Determine the percent Cl in an unknown| |Textbook and lab manual. |27. Read 47-48 in lab manual. |

|determine the percent purity of |sample. | | | |

|chloride in an unknown sample? |Standardize 0.1M silver nitrate. | | | |

|Four Day Aim |Determine the proper indicator needed | | | |

| |for a precipitation titration. | | | |

|Lab Aim – How can we perform a |Calibrate, use and read a pH meter. | |Textbook and lab manual. |28. Read 49-56 in lab manual. |

|potentiometric acid/base titration? |Construct three titration curves. | | | |

|Three Day Aim |Use EXCEL to collect data and draw | | | |

| |curves. | | | |

|Lab Aim – How can we use a |Calibrate, use and read a | |Textbook and lab manual. |29. Read 59-66 in lab manual. |

|spectrophotometer to determine the |spectrophotometer. | | | |

|percent purity of FAS in an unknown |Determine the percent purity of FAS. | | | |

|sample? |Prepare individual solutions for use. | | | |

|Three Day Aim |Use EXCEL to collect data and draw | | | |

| |curves. | | | |

|Aim – How can we balance complex redox|Balance complex redox reactions. | |Textbook and lab manual. |SQ 19 and 20. |

|reactions? |Identify half reactions. | | | |

|One Day Aim | | | | |

|Aim – What can be determined about |Differentiate between different | |Textbook and lab manual. |SQ 21 and 22. |

|complex formations through titrations?|complex ions. | | | |

|One Day Aim |Predict which complex ions are formed | | | |

| |during titrations. | | | |

Section II –

Evaluation Outline

|Quizzes are after: |Tests are after: |

|Ionic equilibrium. |Beginning of term through pH in a hydrolysis reaction. |

|Alpha diagrams. |From Hydrolysis reactions through use of spectrophotometer. |

|Buffer problems with polyprotic acids. |Final exam. |

|Titrations of polyprotic acids and bases. | |

|Complex formations of ions. | |

|Lab Notebooks: |

| |

|Collected after each experiment. |

Resources

|Textbook: |

|Exploring Chemical Analysis by Daniel C. Harris |

|W. H. Freeman and Company; ISBN 0-7167-3042-1; (1997) |

|Laboratory Manual |

|Laboratory Manual for Quantitative Analysis: Tenth Edition by Dr. John C. Ringen |

|Copyright © 2002 by Dr. John C. Ringer |

|Equipment to be used in each lab: |

|Vernier Lab Pro with sensors |

|Networked Computers |

|Software: |

|Microsoft Excel |

|Books: |

|The Essential Guide to Analytical Chemistry by Georg Schwedt, Brooks Haderlie |

|John Wiley & Son Ltd; ISBN: 0471974129; 1 edition (October 24, 1997) |

Supplemental Homework Questions

1. Exactly 156.0 g of aluminum hydroxide were dissolved into 1000. ml of solution. Calculate the equivalent weight of the aluminum hydroxide, the number of moles, millimoles, equivalents, milliequivalents of aluminum hydroxide which are present, the molarity, and the normality.

2. How many grams of pure HCl are in 3000. ml of a 0.2000 N solution of HCl?

3. What are the molarity and normality of a solution which contains 85.6% of phosphoric acid by mass and which has a density of 1.700 g/cc?

4.Using the Henderson-Hasselbach Equation, calculate the pH of a solution containing 0.100 M acetic acid. For acetic acid Ka= 1.75E-5.

5. Using the Henderson-Hasselbach equation, calculate the pH of a solution containing 0.100 M ammonia. For ammonia , Kb= 1.76E-5.

6. Beaker A contains 100. ml of 0.500 M ammonia. Beaker B contains 400. ml of 0.250 M ammonium chloride. These two solutions are now poured together and mixed thoroughly. Assuming that the volumes are additive, what is the final pH of the solution? Which is the proper indicator(s) to be used, and what is their pH range? For ammonia, Kb=1.76E-5.

7. A buffer solution was prepared by dissolving 200.0 ml of 0.500 M acetic acid and 8.204 g of pure sodium acetate in enough water to produce 500.0 ml of solution. Calculate the pH of this buffer solution. Determine the pH range of this buffer solution. For acetic acid Ka=1.75E-5.

8. Write the two dissociation reactions for carbonic acid.

9. What is a tetraprotic acid? Give and example and show how it dissociates.

10. Write out the dissociation reactions and Ka expressions for phosphoric acid.

11. Determine the equivalence point and titration error when you titrate 25.00 ml of 0.1000 N acetic acid with 0.1000 N sodium hydroxide.

12. You titrate 25.00 ml of 0.100 N ammonia with 0.100 N hydrochloric acid. Calculate the pH at the start of the titration, when 20. ml of hydrochloric acid has been added, at the equivalence point, and when 30 ml of hydrochloric acid has been added.

13. The percent transmittance of a solution in a 2.00-cm cell is 60.0%. Calculate the %T of the solution in a 5.00-cm cell.

14. The absorbance of a solution containing 5.00E-3 g/L of a solute in a 1.00-cm cell is 1.00. Calculate: (a) the absorptivity a and (b) the molar absorptivity 0 if the molecular weight of the solute is 125.

15. What is the usefulness of plotting log 0 as a function of the wavelength?

16. Why is it more useful to plot absorbance as a function of concentration instead of transmittance?

17. If the precipitate weighed is U3O8 and the substance sought (the analyte) is U, calculate the gravimetric factor.

18. Exactly 1.000 g of zinc ore was analyzed by dissolving the ore in acid and adding appropriate reagents so that the zinc was precipitated and weighed as Zn2P2O7. The mass of the precipitate was 0.7500 g. What was the percentage of Zn in the ore?

19.The following equations represent two unbalanced redox reactions.

(a) [Acidic solution] H2AsO4Γ + Zn 6 AsH3 + Zn%2

(b) [Basic solution] CrO2Γ + Na2O2 6CrO4ΓΓ + Na+

For each reaction, (1) assign oxidation numbers to each atom in the equation, and then identify the element being oxidized and the element being reduced, (2) identify the oxidizing agent and reducing agent, (3) balance each half reaction, and (4) obtain the complete balanced equation.

20. How much of the substance listed in column B will react with the given amount of material in column A? The half-reactions appear below.

A B

(a) 20.00 ml of 0.1000 M KMnO4..........................______________ml of 0.1000 M H2S

(b) 22.22 ml of 0.1234 M KMnO4..........................______________g of Na2C2O4

Half reactions are as follows:

For both parts: MnO4Γ + 8H+ + 5eΓ 6 Mn++ + 4H2O

For part (a): H2S 6 2H+ + S + 2eΓ

For part (b): C2O4ΓΓ 6 2CO2 + 2eΓ

21. EDTA is commonly available as the disodium salt, dihydrate (M.W. 372.2). How many grams of this salt are required to prepare 250.0 ml of a 0.0500 M EDTA solution?

22. A solution containing zinc nitrate of an unknown concentration is titrated using EDTA and an appropriate indicator. Using 25.00 ml of the zinc solution, 39.48 ml of the 0.0500 M EDTA were required to reach the endpoint. What was the concentration of the zinc solution?

Sample Lesson Plan

Aim: What are some basic concepts involving ionic equilibria?

Anticipatory set:

List at least four properties of acids and bases. (Example acids are sour)

I. Definitions of acids and bases

A. Arrhenius

1. An acid has H in the formula and dissociates in an aqueous (water) solution to produce hydrogen ions, H+.

Example: HCl 6 H+ + ClΓ

2. A base has OH in the formula and dissociates in an aqueous solution to produce hydroxide ions, OHΓ.

Example: NaOH 6 Na+ + OHΓ

B. Bronsted-Lowry

1.An acid is a proton donor; a base is a proton acceptor.

2. Substances which can function as either an acid or a base are amphoteric.

3. If a Bronsted-Lowry acid loses a proton, then its conjugate base is produced. Similarly,

if a Bronsted-Lowry base gains a proton, its conjugate acid is produced.

Example: (1) Dissolving hydrogen chloride gas in water. (2)Dissolving ammonia gas in water.

-Write out the equations for each and identify the conjugate acids and bases.

C. Lewis

1. An acid is an electron pair acceptor.

2. A base is an electron pair donor.

II. Types of electrolytes

A. Strong electrolytes

1.Such solutions conduct electricity very well, because ions are formed completely. Since all the material dissociates into ions, it is not possible to write an equilibrium constant for the dissociation.

-Based on what you remember from AP chemistry, list three types of strong electrolytes and give an example of each.

B. Weak electrolytes

1. Such solutions conduct electricity poorly, because only a fraction of the molecules dissociate into ions. For this reason we can always write an equilibrium constant (either Ka or Kb) for the dissociation reaction.

-List three types of weak electrolytes, give an example of each along with the dissociation reactions.

C. Non-electrolytes

1. Such solutions do not conduct electricity at all, because no dissociation occurs and all of the material remains in molecular form.

-List three examples on non-electrolytes.

III. Molecular, Total Ionic, and Net Ionic Equations

A. Two simple rules for writing ionic equations are as follows:

1. Always write soluble strong electrolytes in ionic form.

2. Keep everything else in molecular form.

Examples:

-For each write out the molecular, total ionic, and net ionic equations.

(1)Neutralization between hydrochloric acid and sodium hydroxide.

(2) Neutralization between acetic acid and potassium hydroxide.

(3) Reaction between a solution of sodium chloride and a solution of silver nitrate to form a silver chloride precipitate.

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