Dystan medical supply company cold packs and hot packs

Determination of the Concentration of Acetic Acid in Vinegar

P U R P O S E Standardize a sodium hydroxide solution using a primary standard acid. Determine the molarity and the percent by mass of acetic acid in vinegar by titration with the standardized sodium hydroxide solution.

I N T R O D U C T I O N The concentration of a solution is the amount of solute (species dissolved) in a given amount of solvent (dissolving agent). A concentrated solution contains a relatively large quantity of solute in a given amount of solvent. Dilute solutions contain relatively little solute in a given amount of solvent. Chemists use specific terms to express the concentration of a solution. Two of these terms are molarity and percent by mass.Molarity is the number of moles of solute per liter of solution.

Molarity ðMÞ ¼ moles of solute liter of solution

ðEq: 1Þ

Percent by mass is the mass in grams of solute per 100 grams of solution.

Percent solute ¼ grams of solute grams of solution

$ 100% ðEq: 2Þ

The grams of solution are the mass of the solute plus the mass of the solvent. For example, a 5.00 % NaCl solution contains 5.00 grams of NaCl and 95.0 grams of H2O in 100.0 grams of solution.

Vinegar is a dilute solution of acetic acid (an organic acid). The molecular formula for acetic acid is CH3COOH. Both the molarity and percent by mass of acetic acid in a vinegar solution can be determined by performing a titration. A titration is a process in which small increments of a solution of known concentration are added to a specified volume of a

E X P E R I M E N T 12

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155

solution of unknown concentration until the stoichiometry for that reaction is attained. Knowing the quantity of the known solution required to complete the titration, we can calculate the unknown solution’s concentration.

In the titration process, a buret is used to dispense small, quantifiable increments of a solution of known concentration (Figure 1a). A typical buret has the smallest calibration unit of 0.1 mL (Figure 1b). Therefore, the volume dispensed from the buret should be estimated to the nearest 0.01 mL. (To be consistent, always read the volume of a liquid inside a buret at the bottom of the liquid’s meniscus).

The purpose of a titration is to determine the equivalence point of the reaction. The equivalence point is reached when the added quantity of one reactant is the exact amount necessary for stoichiometric reaction with another reactant. In this experiment, the equivalence point occurs when the moles of acid in the solution equals the moles of base added in the titration. For example, the stoichiometric amount of 1 mole of the strong base, sodium hydroxide (NaOH), is necessary to neutralize 1 mole of the weak acid, acetic acid (CH3COOH), as indicated in Eq. 3.

NaOHðaqÞ þ CH3COOHðaqÞ ! NaCH3CO2ðaqÞ þH2Oð‘Þ ðEq: 3Þ

NOTE: Free Hþ ions, produced by an acid when it is dissolved in water, do not

actually exist in aqueous solution. Instead, the Hþ ions readily react with water to form

H3O þ ions. Chemists use H3O

þ and Hþ interchangeably when referring to hydrogen

ions in aqueous solution

One indicator that the titration has reached the equivalence point is a sudden change in the pH of the solution. The pH of an aqueous solution is related to its hydrogen ion concentration. Symbolically, the hydrogen ion

Figure 1 Figure 1a) depicts a typical 50-mL buret. Figure 1b) indicates the smallest calibration unit, 0.1 mL, on a typical 50-mL buret

B o b b y S ta n to n /W

a d sw

o rt h /C e n g a g e L e a rn in g

156 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

concentration is written as [H3O þ] (see Note). pH is defined as the negative

of the base 10 logarithm of the hydrogen ion concentration.

pH ¼ &log½H3Oþ( ðEq: 4Þ

The common base 10 logarithm of a number is the number that 10 must be raised to produce the original number. For example, the logarithm of 1.00 $ 10&7 is &7. The pH scale is a convenient, short hand method of expressing the acidity or basicity of a solution. The pH of an aqueous solution is typically a number between 0 and 14. Solutions having a pH < 7 are acidic. Solutions with pH ¼ 7 are neutral. Solutions having a pH > 7 are basic. For example, a solution having [H3O

þ] ¼ 2.35 $ 10&2Mwould have a pH of 1.629 and is acidic.

In this experiment, we will measure the pH of a solution using the MeasureNet pH electrode. The titration is initiated by inserting a pH electrode into a beaker containing the acid solution (pH is in the 3-5 range). As sodium hydroxide, NaOH, is incrementally added to the acid solution, some of the hydrogen ions are neutralized. As the hydrogen ion concen- tration decreases, the pH of the solution will gradually increase. When sufficient NaOH is added to completely neutralize the acid (most of the H3O

þ ions are removed from solution), the next drop of NaOH added causes a sudden, sharp increase in pH (Figure 2). The equivalence point is the center of the curve in the region where the pH changes sharply for any acid-base reaction involving 1:1 reaction stoichiometry (Figure 2). The volume of base required to completely neutralize the acid is determined at the equivalence point of the titration.

In this experiment, we will titrate a vinegar sample with a stand- ardized sodium hydroxide solution. To standardize the sodium hydroxide solution, we will initially prepare a primary standard acid solution. In general, primary standard solutions are produced by dissolving a weighed quantity of a pure acid or base in a known volume of solution.

Primary standard acids and bases have several common character- istics: 1) they must be available in at least 99.9% purity, 2) they must have a high molar mass to minimize errors in weighing, 3) they must react by one invariable reaction, 4) they must be stable upon heating, and 5) they must be soluble in the solvent of interest. Potassium hydrogen phthalate, KHC8H4O4, and oxalic acid, (COOH)2, are commonly used primary

! 2 0 1 0 B ro o ks /C o le , C e n g a g e L e a rn in g Figure 2

Acid-base titration curve for a weak acid titrated with NaOH. The pH of the solution is plotted as a function of the volume of NaOH added. From the equivalence point, the volume of NaOH required to neutralize the weak acid is determined to be 11.6 mL

Weak Acid Titrated with NaOH

0

2

4

6

8

10

12

14

0 2 4 6 8 10 12 14

mL NaOH

pH

11.6 mLequivalence point

Experiment 12 n Determination of the Concentration of Acetic Acid in Vinegar 157

standard acids. Sodium carbonate, Na2CO3, is the most commonly used primary standard base.

Most acids and bases (e.g., HCl, CH3COOH, NaOH and KOH) are not available as primary standards. To standardize one of these acid or base solutions, we titrate the solution with a primary standard. In this experi- ment, we will titrate a freshly prepared NaOH solution with potassium hydrogen phthalate (often abbreviated as KHP). The equation for the reaction of KHP with NaOH is

KHC8H4O4ðaqÞ þNaOHðaqÞ ! KNaC8H4O4ðaqÞ þH2Oð‘Þ ðEq: 5Þ

Once the sodium hydroxide solution has been standardized, it will be used to titrate 10.00 mL aliquots of vinegar. The equation for the reaction of vinegar with NaOH is

CH3COOHðaqÞ þNaOHðaqÞ ! NaCH3COOðaqÞ þH2Oð‘Þ ðEq: 6Þ

Knowing the standardized NaOH concentration and using Equation 6, we can determine the molarity and percent by mass of acetic acid, CH3COOH, in the vinegar solution.

Standardizing a Basewith KHP (KHC8H4O4)

To standardize a solution of NaOH, a known mass of KHP is dissolved in enough water to just dissolve the sample. A buret is used to titrate NaOH solution into the beaker containing the KHP solution. The molarity of the NaOH solution is determined by first calculating the number of moles KHP dissolved in solution. Equation 5 indicates that one mole of NaOH is required to neutralize one mole of KHP. This stoichiometric ratio and the moles of KHP in solution are used to calculate the moles of NaOH required to neutralize the KHP. The volume of NaOH used is the titration is determined at the equivalence point from a plot of pH of the solution versus milliliters of NaOH added. The molarity of the NaOH solution is calculated by dividing the moles of NaOH by the volume of NaOH in liters used to neutralize the KHP solution.

Determining theAcetic Acid Concentration inVinegar

A 10.00 mL aliquot of vinegar is titrated with the standardized NaOH solution. To determine the molarity of acetic acid in vinegar, we first cal- culate the moles of NaOH required to neutralize the acetic acid in the sample. The moles of NaOH required is the product of the molarity of the standardized NaOH solution times the volume of NaOH used in the titration. Equation 6 indicates that one mole of NaOH is required to neu- tralize one mole of acetic acid. This stoichiometric ratio and the moles of NaOH used in the titration are used to calculate the moles of acetic acid in the vinegar sample. The molarity of the acetic acid is obtained by dividing the moles of acetic acid in the sample by the liters of vinegar solution used in the titration.

Dividing the mass of acetic acid in vinegar by the mass of the vinegar solution, then multiplying by 100%, yields the mass percent of acetic acid in vinegar. The mass of acetic acid is the product of the moles of acetic acid in the sample times the molar mass of acetic acid. The mass of the solution is equal to the volume of the vinegar used in the titration times the density

158 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

of vinegar solution. In this experiment, assume the density of vinegar is the same as that for water, 1.00 g/mL at ambient temperature.

P R O C E D U R E

C A U T I O N

Students must wear departmentally approved eye protection while performing

this experiment. Wash your hands before touching your eyes and after

completing the experiment.

Part A ^Standardization of a SodiumHydroxide Solution

1. Prepare 150 mL of approximately 0.6 M sodium hydroxide solution from solid NaOH. Check the calculations with your laboratory instructor prior to preparing the solution. Should your calculations be recorded in the Lab Report?

2. Add approximately 1.5 grams of potassium hydrogen phthalate (KHP) to a 250-beaker. Should the exact mass of the sample be recorded in the Lab Report, and to how many significant figures? Add sufficient dis- tilled water to the beaker to dissolve the KHP. Should the volume of water used be recorded in the Lab Report, and to how many significant figures?

3. Stir to completely dissolve the KHP. Why must the KHP be completely dissolved before beginning the titration? Add enough distilled water to the beaker to ensure that the cut-out notch on the tip of the pH elec- trode is completely submerged in solution. Why must the cut-out notch be completely submerged in solution?

4. See Appendix F – Instructions for Recording a Titration Curve Using the MeasureNet pH Probe and Drop Counter. Complete all steps in Appendix F before proceeding to Step 5 below.

5. Repeat Steps 2–4 to perform a second trial to standardize the NaOH solution.

6. Steps 7–10 are to be completed after the laboratory period is concluded (outside of lab). Proceed to Step 11, Determination of Acetic Acid Concentration in Vinegar.

7. From the tab delimited files you saved, prepare plots of the pH versus volume of NaOH added using Excel (or a comparable spreadsheet program). Instructions for plotting pH versus volume curves using Excel are provided in Appendix B-4.

8. How do you determine the volume of NaOH required to neutralize the KHP solution in each titration? Should this volume be recorded in the Lab Report, and to how many significant figures?

9. How do you determine the molarity of the sodium hydroxide solution in Trials 1 and 2?

10. What is the average molarity of the sodium hydroxide solution? The average molarity is the concentration of the standardized NaOH solution.

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Experiment 12 n Determination of the Concentration of Acetic Acid in Vinegar 159

Part B ^ Determination of Acetic Acid Concentration inVinegar

11. Transfer 10.00 mL of vinegar to a clean, dry 250-mL beaker using a 10 mL volumetric pipet. Add sufficient water to the acid so that the cut out notch on the pH electrode tip is completely submerged. Should the volume of water be recorded in the Lab Report, and to how many significant figures?

12. See Appendix F–Instructions for Recording a Titration Curve Using the MeasureNet pH Probe and Drop Counter. Complete all steps in Appendix F before proceeding to Step 13 below.

13. Repeat Steps 11 and 12 to perform a second titration of vinegar with the standardized NaOH.

14. From the tab delimited files you saved, prepare plots of the pH versus volume of NaOH added using Excel (or a comparable spreadsheet program). Instructions for plotting pH versus volume curves using Excel are provided in Appendix B-4.

15. How do you determine the volume of NaOH required to neutralize vinegar in Trials 1 and 2? Should this volume be recorded in the Lab Report, and to how many significant figures?

16. How do you determine the molarity of acetic acid in vinegar for Trials 1 and 2?

17. What is the average molarity of acetic acid in the vinegar sample?

18. How do you determine the percent by mass of acetic acid in the vinegar sample?

19. What is the average percent by mass of acetic acid in the vinegar sample?

160 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

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Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section . . . . . . . . . . . . . . . Date . . . . . . . . . . . . . . .

Instructor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12 E X P E R I M E N T 1 2

Lab Report Part A – Standardization of a Sodium Hydroxide Solution

Preparation of 150 mL of 0.6 M sodium hydroxide solution.

Standardization of NaOH with KHP data – Trial 1

Why must the KHP be completely dissolved before beginning the titration?

Standardization of NaOH with KHP data – Trial 2

161

How do you determine the volume of NaOH required to neutralize the KHP solution in each Trial?

How do you determine the molarity of the sodium hydroxide solution in Trials 1 and 2?

What is the average molarity of the sodium hydroxide solution?

Part B – Determination of the Concentration of Acetic Acid in Vinegar

Titration of acetic acid with standardized NaOH data – Trial 1

162 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

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Titration of acetic acid with standardized NaOH data – Trial 2

How do you determine the volume of NaOH required to neutralize vinegar in each Trial?

How do you determine the molarity of acetic acid in vinegar for Trials 1 and 2?

What is the average molarity of acetic acid in the vinegar sample?

How do you determine the percent by mass of acetic acid in vinegar for Trials 1 and 2?

Experiment 12 n Determination of the Concentration of Acetic Acid in Vinegar 163

What is the average percent by mass of acetic acid in the vinegar sample?

164 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

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Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section . . . . . . . . . . . . . . . Date . . . . . . . . . . . . . . .

Instructor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12 E X P E R I M E N T 1 2

Pre-Laboratory Questions 1. 1.802 grams of KHP is dissolved in 20.0 mL of distilled water. The titration curve below is for the

titration of the KHP solution with NaOH. See Eq. 5 for the balanced equation for the reaction.

Titration of KHP with NaOH

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

mL NaOH

pH

equivalence point 15.3 mL

a. Determine the number of moles of KHP in the solution.

b. Determine the number of moles of NaOH required to neutralize the KHP.

c. What is the molarity of the NaOH solution?

165

2. A 10.00 mL aliquot of vinegar is titrated with the same NaOH solution standardized in Question 1. The titration curve below is for the titration of vinegar with the standardized NaOH solution. See Eq. 6 for the balanced equation for the reaction.

Titration of Vinegar with NaOH

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

mL of NaOH

pH

equivalence point 14.7 mL

a. Determine the number of moles of NaOH required to neutralize the acetic acid in the vinegar sample.

b. Determine the number of moles of CH3COOH in the vinegar sample.

166 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

! 2 0 1 0 B ro o ks /C o le , C e n g a g e L e a rn in g

c. What is the molarity of CH3COOH in the vinegar sample?

d. Determine the mass of acetic acid in the vinegar sample.

e. Determine the mass of the 10.00 mL aliquot of vinegar. The density of vinegar is 1.00 g/mL.

f. Determine the percent by mass of acetic acid in the vinegar sample.

Experiment 12 n Determination of the Concentration of Acetic Acid in Vinegar 167

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Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section . . . . . . . . . . . . . . . Date . . . . . . . . . . . . . . .

Instructor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12 E X P E R I M E N T 1 2

Post-Laboratory Questions 1. When performing this experiment, a student mistakenly used impure KHP to standardize the NaOH

solution. If the impurity is neither acidic nor basic, will the percent by mass of acetic acid in the vinegar solution determined by the student be too high or too low? Justify your answer with an explanation.

2. When preparing a NaOH solution, a student did not allow the NaOH pellets to completely dissolve before standardizing the solution with KHP. However, by the time the student refilled the buret with NaOH to titrate the acetic acid, the remaining NaOH pellets had completely dissolved. Will the molarity of acetic acid in the vinegar solution, determined by the student, be too high or too low? Justify your answer with an explanation.

169

3. Distilled water normally contains dissolved CO2. When preparing NaOH standard solutions, it is important to use CO2 free distilled water. How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution’s concentration? (Hint: Use your textbook, the internet, etc. to research the term acid anhydride.)

170 Experiments in General Chemistry Featuring MeasureNet n Stanton et al.

Front Cover
Title Page
Copyright
Contents
Preface
Acknowledgments
Common Laboratory Glassware and Equipment
Safety Rules
Safety Quiz
EXPERIMENT 1 Densities of Some Liquids and Solids
OBJECTIVES
INTRODUCTION
PROCEDURE
EXPERIMENT 1 Lab Report
SHOW ALL WORK TO RECEIVE FULL CREDIT
EXPERIMENT 1 Pre-Laboratory Questions
EXPERIMENT 1 Post-Laboratory Questions
EXPERIMENT 2 Specific Heat of Substances
OBJECTIVES
INTRODUCTION
SAMPLE CALCULATIONS
Determination of the Calorimeter Constant
Determination of the Specific Heat of a Solid
PROCEDURE
Part A - Determination of the Calorimeter Constant
Part B - Determination of the Specific Heat of a Solid
EXPERIMENT 2 Lab Report
Part A – Determination of the Calorimeter Constant
Part B – Determination of the Specific Heat of a Solid
EXPERIMENT 2 Pre-Laboratory Questions
EXPERIMENT 2 Post-Laboratory Questions
EXPERIMENT 3 Chromatography
OBJECTIVES
INTRODUCTION
PROCEDURE
Part A. Dye Separation of NonpermanentMarker Inks
Part B. Identification of TransitionMetal Ions Present in an Unknown Solution
EXPERIMENT 3 Lab Report
SHOW ALL WORK TO RECEIVE FULL CREDIT.
EXPERIMENT 3 Pre-Laboratory Questions
SHOW ALL WORK TO RECEIVE CREDIT.
EXPERIMENT 3 Post-Laboratory Questions
EXPERIMENT 4 Determination of the Percent by Mass of the Components in a Mixture by Thermal Gravimetric Analysis
OBJECTIVES
INTRODUCTION
Heating to Constant Mass
PROCEDURE
EXPERIMENT 4 Lap Report
SHOW ALL WORK TO RECEIVE FULL CREDIT.
EXPERIMENT 4 Pre-Laboratory Questions
SHOW ALL WORK TO RECEIVE CREDIT.
EXPERIMENT 4 Post-Laboratory Questions
SHOW ALL WORK TO RECEIVE CREDIT.
EXPERIMENT 5 Thermal Insulating Materials: A Self-Directed Experiment
OBJECTIVES
INTRODUCTION
PROCEDURE
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 6 Reaction Stoichiometry
OBJECTIVES
INTRODUCTION
PROCEDURE
Set up the Measure Net Workstation to Record pH
Part A - Identification of an Unknown PowderedMetal by Reaction with HCl
Part B - Identification of an UnknownMetal Nitrate Solution via Precipitation with NaOH
EXPERIMENT 6 Lab Report
Part A - Identi.cation of an Unknown Powdered Metal by Reaction with HCl
Part B - Identi.cation of an Unknown Metal Nitrate Solution via Precipitation with NaOH
EXPERIMENT 6 Pre-Laboratory Questions
EXPERIMENT 6 Post-Laboratory Questions
EXPERIMENT 7 Types of Chemical Reactions
OBJECTIVES
INTRODUCTION
I. Redox Reactions
II. Metathesis Reactions
PROCDURE
Redox: Combination Reactions
Redox: Decomposition Reactions
Redox: Displacement Reactions
Unknown - Determine Activity Series forTwo Metals
Metathesis: Precipitation Reactions (Nonredox)
Metathesis: Acid-Base Reactions (Nonredox)
Metathesis - Amphoteric Hydroxides andComplex Ion Formation
Unknown - Identifying Ions in Solution
EXPERIMENT 7 Lab Report
EXPERIMENT 7 Pre-Laboratory Questions
EXPERIMENT 7 Post-Laboratory Questions
EXPERIMENT 8 Identification of Metal Ions and Inorganic Compounds by their Chemical Reactions
OBJECTIVES
INTRODUCTION
PROCEDURE
Part A - Identification of Metal Ions in Aqueous Solution
Part B - Identification of Inorganic Compounds in Aqueous Solution
EXPERIMENT 8 Lab Report
Part A – Identification of Metal Ions in Aqueous Solution
Part B – Identification of Inorganic Compounds in Aqueous Solution
EXPERIMENT 8 Pre-Laboratory Questions
EXPERIMENT 8 Post-Laboratory Questions
EXPERIMENT 9 Gravimetric Analysis of a Chloride, Sulfate, or Carbonate Compound
OBJECTIVES
INTRODUCTION
Sample Calculation to Determine the Volume of the Precipitating Reagent
Sample Calculation for the Mass Composition of the Unknown Sample
PROCEDURE
Part A - Characterization of the Unknown Compound as a Chloride, Sulfate, or Carbonate Compound
Part B - Determination of the Percent by Mass of Cl[Sup(-)], SO[Sub(4)] [Sup(2-), or CO[Sub(3)] [sup(2-)] in the Unknown Sample
EXPERIMENT 9 Lab Report
Part A – Characterization of the Unknown Compound as a Chloride, Sulfate, or Carbonate Compound
Part B – Determination of the Percent by Mass of Cl , SO4 2 , or CO3 2 in the Unknown Sample
EXPERIMENT 9 Pre-Laboratory Questions
EXPERIMENT 9 Post-Laboratory Questions
EXPERIMENT 10 Emission Analysis of Aqueous Solutions of Groups IA and IIA Metal Salts
PURPOSE
INTRODUCTION
PROCEDURE
Calculations and Experimental Analysis to be Completed Outside of Lab
EXPERIMENT 10 Lab Report
EXPERIMENT 10 Pre-Laboratory Questions
EXPERIMENT 10 Post-Laboratory Questions
EXPERIMENT 11 Determination of Chromium(VI) Concentrations Via Absorption Spectroscopy
PURPOSE
INTRODUCTION
Metal Ion Concentrations in Solution
Standard Solution Preparation
Serial Dilutions
PROCEDURE
EXPERIMENT 11 Lab Report
EXPERIMENT 11 Pre-Laboratory Questions
EXPERIMENT 11 Post-Laboratory Questions
EXPERIMENT 12 Determination of the Concentration of Acetic Acid in Vinegar
PURPOSE
INTRODUCTION
Standardizing a Base with KHP (KHC[Sub(8)]H[Sub(4)]O[sub(4)])
Determining theAcetic Acid Concentration inVinegar
PROCEDURE
Part A - Standardization of a Sodium Hydroxide Solution
Part B - Determination of Acetic Acid Concentration in Vinegar
EXPERIMENT 12 Lab Report
Part A – Standardization of a Sodium Hydroxide Solution
Part B – Determination of the Concentration of Acetic Acid in Vinegar
EXPERIMENT 12 Pre-Laboratory Questions
EXPERIMENT 12 Post-Laboratory Questions
EXPERIMENT 13 Solubility, Polarity, Electrolytes, and Nonelectrolytes
PURPOSE
INTRODUCTION
PROCEDURE
Part A - Determination of the Polar/Nonpolar Nature of Several Compounds
Part B - Relative Solubilities of SomeIonic Compounds in Water
Part C - Electrical Conductivity of Several Solutions
EXPERIMENT 13 Lab Report
Part A – Determination of the Polar/Nonpolar Nature of Several Compounds
Part B – Relative Solubilities of Some Ionic Compounds
Part C – Electrical Conductivity of Several Solutions
EXPERIMENT 13 Pre-Laboratory Questions
EXPERIMENT 13 Post-Laboratory Questions
EXPERIMENT 14 Determination of the Cause of a ''Fish-Kill'' in the Clark Fork of the Columbia River: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 15 Quality Control for the Athenium Baking Soda Company: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 16 Gas Laws
PURPOSE
INTRODUCTION
Part A - Ideal Gas Law
Part B - Boyle’s Law
PROCEDURE
Part A - Determination of the Molar Mass of aVolatile Compound
Part B - Pressure-Volume Measurements for an Air Sample
EXPERIMENT 16 Lab Report
EXPERIMENT 16 Pre-Laboratory Questions
EXPERIMENT 16 Post-Laboratory Questions
EXPERIMENT 17 Colligative Properties
PURPOSE
INTRODUCTION
Determination of the Molar Mass of an Unknown, Nonelectrolyte Compound from Freezing Point Depression
Determination of the van’t Hoff Factor of an Unknown, Electrolyte Compound
PROCEDURE
Part A - Determination of the Freezing Point of the Pure Solvent
Part B - Determination of the Freezing Point of a Nonelectrolyte, Unknown Solution
Part C - Determination of the van’t Hoff Factor for a Strong, Electrolyte Unknown
EXPERIMENT 17 Lab Report
Part B – Determination of the Freezing Point of a Nonelectrolyte, Unknown Solution
Part C – Determination of the van’t Hoff Factor for a Strong, Electrolyte Unknown
EXPERIMENT 17 Pre-Laboratory Questions
EXPERIMENT 17 Post-Laboratory Questions
EXPERIMENT 18 Soaps and Detergents
PURPOSE
INTRODUCTION
PROCEDURE
Part A - Soap Preparation
Part B - Comparison of Soap and Detergent Properties-Precipitation and Emulsification
Part C - Comparison of the Cleaning Abilities of a Soap and Two Detergents
EXPERIMENT 18 Lab Report
Part A – Soap Preparation
Part B – Comparison of Soap and Detergent Properties – Precipitation and Emulsi.cation
Part C – Cleansing Comparison of a Soap and Two Detergents
Part D – Comparison of the Cleaning Abilities of a Soap and Two Detergents
EXPERIMENT 18 Pre-Laboratory Questions
EXPERIMENT 18 Post-Laboratory Questions
EXPERIMENT 19 Thermal Energy Associated with Physical and Chemical Changes
PURPOSE
BACKGROUND INFORMATION
Determination of the Calorimeter Constant
Sample Calculation for Determining theMolar Heat of Reaction
PROCEDURE
Part A - Determination of the Calorimeter Constant
Part B - Determination the Molar Heat of Dissolution of aSalt
Part C - Determination of the Molar Heat of Reaction of an Acid-Base Reaction
Part D - Determination of theMolar Heat of Reaction of a Precipitation Reaction
EXPERIMENT 19 Lab Report
Part A – Determination of the Calorimeter Constant
Part B – Determination of the Heat of Dissolution of a Salt
Part C – Determination of the Molar Heat of Reaction of an Acid-Base Reaction
EXPERIMENT 19 Pre-Laboratory Questions
EXPERIMENT 19 Post-Laboratory Questions
EXPERIMENT 20 Hess's Law
PURPOSE
INTRODUCTION
PROCEDURE
Part A - Determination of the Calorimeter Constant
Part B - Determination of the Heat of Neutralization for Several Acid-Base Reactions
EXPERIMENT 20 Lab Report
Part A – Determination of the Calorimeter Constant
Part B – Determination of the Heat of Neutralization for Several Acid-Base Reactions
EXPERIMENT 20 Pre-Laboratory Questions
EXPERIMENT 20 Post-Laboratory Questions
EXPERIMENT 21 Determination of the Heat of Neutralization of a Variety of Strong Acids and Bases: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 22 Dystan Medical Supply Company – Cold Packs and Hot Packs: A Self-Directed Experiment
PUEPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 23 Chemical Kinetics
PURPOSE
INTRODUCTION
Method of Initial Rates for Determination of Reaction Orders
Integrated Rate Laws
Using the Measure Net Colorimeter to Monitor Changes in the Concentration of a Colored Reactant
Determination of the Rate Law for the Iodination of Acetone in Acidic Solution
Determination of the Rate Law for the Reaction of Crystal Violet with Sodium Hydroxide
PROCEDURE
Part A - Determination of the Rate Law for the Iodination of Acetone in Acidic Solution
Part B - Determination of the Rate Law for the Reaction of Crystal Violet with Sodium Hydroxide
EXPERIMENT 23 Lab Report
Part A – Determination of the Rate Law for the Iodination of Acetone in Acidic Solution
EXPERIMENT 23 Pre-Laboratory Questions
EXPERIMENT 23 Post-Laboratory Questions
EXPERIMENT 24 Le Chaˆtelier’s Principle
PURPOSE
INTRODUCTION
Effect of Concentration Changes on Systems at Equilibrium
Effect of Changing pH on a Complex Ion Equilibrium
Effect of Changing Reaction Temperature on Equilibrium
PROCEDURE
Part A - Effect of Concentration Changes on Systems at Equilibrium
Part B - Effect of Changing pH on a Complex Ion Equilibrium
Part C - Effect of Changing Reaction Temperature on an Equilibrium System
EXPERIMENT 24 Lab Report
Part A – Effect of Concentration Changes on Systems at Equilibrium
Part B – Effect of Changing pH on a Complex Ion Equilibrium
Part C – Effect of Changing Reaction Temperature on an Equilibrium System
EXPERIMENT 24 Pre-Laboratory Questions
EXPERIMENT 24 Post-Laboratory Questions
EXPERIMENT 25 Determination of a Reaction Equilibrium Constant Using Absorption Spectroscopy
PURPOSE
INTRODUCTION
Concentrations of Metals in Solution
Use of ‘‘ICE’’ Tables for Calculating Equilibrium Concentrations of Reactants and Products
PROCEDURE
Part A - Preparation of Five Standard Fe(SCN)[Sup(2+)] Solutions
Part B - Absorption Measurements for the Standard Solutions and Preparation of the Beer- Lambert Curve
Part C - Equilibrium Solution Preparation and Absorption Measurements: Finding K[sub(c)]
EXPERIMENT 25 Lab Report
Part A – Preparation of Five Standard Fe(SCN)[Sup(2+)] Solutions
Part B – Absorption Measurements for the Standard Solutions and Preparation of the Beer-Lambert Curve
Part C – Equilibrium Solution Preparation and Absorption Measurements: Finding K[Sub(c)]
EXPERIMENT 25 Pre-Laboratory Questions
EXPERIMENT 25 Post-Laboratory Questions
EXPERIMENT 26 Determination of K[Sub(a)] or K[Sub(b)] for an Acid or Base
PURPOSE
INTRODUCTION
Acidity or Basicity of Salt Solutions
Sample Calculation to Determine the Ka Value of a Weak Acid fromTitration with NaOH
Sample Calculation for the Determination of K[Sub(a)] from the Initial Concentration and pH of aWeak Acid Solution
PROCEDURE
Part A - Determination of the Ionization Constant (K[Sub(a)] or K[Sub(b)]) of an Unknown Solution
Part B - Determination of the Ionization Constant (K[Sub(a)] or K[Sub(b)]) of an Unknown Solution from the Initial Concentration and pH or pOH of the Solution
EXPERIMENT 26 Lab Report
Part A – Determination of the Ionization Constant (Ka or Kb) of an Unknown Solution
Part B – Determination of the Ionization Constant (K[Sub(a)] or K[Sub(b)]) of an Unknown
EXPERIMENT 26 Pre-Laboratory Questions
EXPERIMENT 26 Post-Laboratory Questions
EXPERIMENT 27 pH and Buffer Solutions
PUROSE
INTRODUCTION
pH Measurements
Buffer Solutions
Henderson-Hasselbalch Equation
Preparing a Buffer Solution with a Specific pH
PROCEDURE
Part A - Set up the MeasureNetWorkstation to Record pH.
Part B - pHMeasurements
Part C - pH Changes of a DistilledWater Sample before and after the Addition of a Strong Acid or Base
Part D - Preparation of an Acidic Buffer Solution
Part E - Preparation of a Basic Buffer Solution
EXPERIMENT: Lab Report
Part B – pH Measurements
Part C – pH Changes of a Distilled Water Sample Before and After Addition of a Strong Acid or Base
Part D – Preparation of an Acidic Buffer Solution
Part E – Preparation of a Basic Buffer Solution
EXPERIMENT 27 Pre-Laboratory Questions
EXPERIMENT 27 Post-Laboratory Questions
EXPERIMENT 28 Identifying an Unknown Weak Acid or Weak Base: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 29 Hydrometallurgy to Analyze a Chromite Sample: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 30 Determination of Iron Content in a Food Sample: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 31 Quality Control for GlassOff: A Self-Directed Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
EXPERIMENT 32 What is in this Container: A Capstone Experiment
PURPOSE
INTRODUCTION
PROCEDURE
LIST OF CHEMICALS
LIST OF SPECIAL EQUIPMENT
Appendices
A-1 Instructions for Initializing the MeasureNet Workstation to Record a Thermogram
A-2 Instructions for Recording a Thermogram to Determine the Styrofoam Cup Calorimeter Constant
A-3 Instructions for Recording a Thermogram to Determine the Enthalpy Change for a Neutralization Reaction
A-4 Instructions for Recording a Thermogram to Determine the Enthalpy Change for a Physical or Chemical Process
B-1 Instructions for Plotting Excel XY Thermograms for Calorimetry
B-2 Excel Instructions for Performing Linear Regression Analysis
B-3 Instructions for Plotting Multiple Excel XY Thermograms for Freezing Point Depression
B-4 Instructions for Plotting Excel Titration Curves
B-5 Instructions for Plotting Excel XY Emission Intensity Versus Wavelength Curves
C-1 Format for Writing the Procedure Proposal
C-2 Format for Writing the Formal Lab Report
D: Instructions for Recording an Absorbance Spectrum using the MeasureNet Spectrophotometer
E: Instructions for Recording an Emission Spectrum Using the MeasureNet Spectrophotometer
F: Instructions for Recording a Titration Curve Using the MeasureNet pH Probe and Drop Counter