Related concepts Kohlrausch s law, equivalent conductivity, temperature dependence of conductivity, Ostwald s dilution law.

Size: px
Start display at page:

Download "Related concepts Kohlrausch s law, equivalent conductivity, temperature dependence of conductivity, Ostwald s dilution law."

Transcription

1 Conductivity of strong and weak electrolytes TEC Related concepts Kohlrausch s law, equivalent conductivity, temperature dependence of conductivity, Ostwald s dilution law. Principle It is possible to differentiate between strong and weak electrolytes by measuring their electrical conductance. Strong electrolytes follow Kohlrausch s law, whereas weak electrolytes are described by Ostwald s dilution law. The examination of the concentration dependence of the conductivity allows the molar conductivities of infinitely diluted electrolytes to be determined, and facilitates the calculation of the degree of dissociation and the dissociation constants of weak electrolytes. Equipment 1 Cobra4 Wireless Manager Cobra4 Wireless-Link Cobra4 Sensor Unit Conductivity Software measure Cobra Holder for Cobra4 with support rod Magnetic stirrer, mini Magnetic stirrer bar, l = 15 mm Retort stand, h = 750 mm Right angle clamp Spring balance holder Support rod with hole, l = 100 mm Glass beaker, 250 ml, tall Glass beaker, 150 ml, tall Volumetric flask, 250 ml Volumetric flask, 500 ml Volumetric flask, 1000 ml Funnel, glass, d o = 80 mm Volumetric pipette, 1 ml Volumetric pipette, 5 ml Volumetric pipette, 100 ml Pipettor Pipette dish Pasteur pipettes Rubber bulbs Set balance Sartorius CPA 623S and software, 230 V, 620 g / g 1 Weighing dishes, 80 x 50 x 14 mm Spoon Cristallizing dish, 320 ml Wash bottle, 500 ml Desiccator Porcelain plate for desiccators Silicone grease, 50 g Silica gel, orange, granulated, 500 g Acetic acid, 1 M, 1000 ml Standard solution, 1413 S / cm,460 ml Potassium chloride, 250 g Water, distilled, 5 l Additional equipment PC with USB interface, Windows XP 1 or higher Fig. 1: Experimental set up. P PHYWE Systeme GmbH & Co. KG All rights reserved 1

2 TEC Conductivity of strong and weak electrolytes Safety instructions When handling chemicals, you should wear suitable protective gloves, safety goggles, and suitable clothing. Please refer to the appendix for detailed safety instructions. Tasks 1. Determine the concentration dependence of the electrical conductivity of potassium chloride and acetic acid. 2. Calculate the molar conductivity using data from the measurements taken and determine the molar conductivity at infinite dilution by extrapolation. 3. Determine the dissociation constant of acetic acid. Set-up and procedure - Prepare the solutions required for the experiment as follows: molar KCl solution: Weigh g of dried potassium chloride into a 1000 ml volumetric flask, add some distilled water to dissolve it, and then make up to the calibration mark with distilled water molar KCl solution: Weigh g of dried potassium chloride into a 1000 ml volumetric flask, add some distilled water to dissolve it, and then make up to the calibration mark with distilled water molar KCl solution: Pipette 25 ml of the 0.1 molar KCl solution into a 250 ml volumetric molar KCl solution: Pipette 25 ml of the 0.05 molar KCl solution into a 250 ml volumetric molar KCl solution: Pipette 5 ml of the 0.1 molar KCl solution into a 500 ml volumetric molar KCl solution: Pipette 5 ml of the 0.05 molar KCl solution into a 500 ml volumetric molar KCl solution: Pipette 1 ml of the 0.1 molar KCl solution into a 1000 ml volumetric molar CH 3 COOH solution: Pipette 100 ml of the 1 molar acetic acid solution into a 1000 ml volumetric molar CH 3 COOH solution: Pipette 50 ml of the 1 molar acetic acid solution into a 1000 ml volumetric molar CH 3 COOH solution: Pipette 25 ml of the 0.1 molar acetic acid solution into a 250 ml volumetric molar CH 3 COOH solution: Pipette 25 ml of the 0.05 molar acetic acid solution into a 250 ml volumetric molar CH 3 COOH solution: Pipette 5 ml of the 0.1 molar acetic acid solution into a 500 ml volumetric molar CH 3 COOH solution: Pipette 5 ml of the 0.05 molar acetic acid solution into a 500 ml volumetric molar CH 3 COOH solution: Pipette 1 ml of the 0.1 molar acetic acid solution into a 1000 ml volumetric - Set up the experiment as shown in Fig Connect the conductivity probe to the Cobra4 Sensor-Unit Conductivity +. 2 PHYWE Systeme GmbH & Co. KG All rights reserved P

3 Conductivity of strong and weak electrolytes TEC - Combine the Cobra4 Sensor Unit Conductivity + with the Cobra4 Wireless-Link. - Start the PC and connect the Cobra4 Wireless Manager with a USB socket of the computer. - After the Cobra4 Wireless-Link has been switched on, the sensor is automatically recognized. An ID number (01) is allocated to the sensor, which is indicated in the display of the Cobra4 Wireless- Link. - Call up the Measure programme and boot the experiment Conductivity of strong and weak electrolytes: potassium chloride (experiment > open experiment). The measurement parameters for this experiment are loaded now. - For calibration: Pour some standard solution into a beaker and immerse the well-rinsed probe into the solution (Advice: Both platinum electrodes of the probe have to be covered completely with the solution). - In the Cobra4 Navigator under Devices double-click the Conductivity symbol. Now you can change some measurement parameters. - Enter the value for the conductivity at a given temperature under the menu point Calibration. You can find this value on the label of the standard solution (at 25 C C = 1413 µs / cm, see Fig. 2). Click the Apply button and finish the calibration with OK. - Procedure: When measuring the conductivity, always begin with the solution having the lowest concentration in each series of measurements. Before each new measurement, thoroughly rinse the probe, the glass beaker and the magnetic stirrer bar, first with distilled water and then with the solution to be subsequently measured. - Determine the conductivity of the distilled water that is used for the dilution of the solutions and note the result. This is to enable the conductivity of the water used to be taken into consideration in the evaluation. - Place a glass beaker containing a magnetic stirrer bar on the magnetic stirrer. Pour the first potassium chloride solution to be measured into the glass beaker, and immerse the previously well-rinsed conductivity cell to a depth of approximately 5 cm in the solution. - Adjust the magnetic stirrer bar to a medium stirring speed (Note: The stirring bar must not touch the measurement cell). - Start the measurement with. Record the first value by pressing. - Subsequently determine the respective conductivities of the other solutions by pressing, whereby in each case the solution with the next higher concentration is measured. - While recording the measuring series, pay strict attention to cleanliness as even the slightest trace of contaminants (e.g. by carrying over some of one solution into another) would result in the registration of erroneous data. - Stop the measurement by pressing. - Send all data to measure (see Fig. 3). - In measure click on to get the graph for conductivity. Fig. 2: Settings for the calibration mode of the sensor. - Open the display options with. - Change the setting as shown in fig. 4. Fig. 3: Window which appears after measurement. P PHYWE Systeme GmbH & Co. KG All rights reserved 3

4 TEC Conductivity of strong and weak electrolytes - Open the data table with. - Exchange the x values manually with the given concentration values in the right order. - Save the measurement (File > Save meausrement as ). - Fig. 5 shows the graph as it is now presented by the programme. Fig. 4: Settings for the conductivity of KCl solutions as functions of the concentration. Fig. 5: Conductivity of potassium chloride solutions as a function of the concentration. - Call up the Measure programme and boot the experiment Conductivity of strong and weak electrolytes: acetic acid (experiment > open experiment). The measurement parameters for this experiment are loaded now. - Carry out the measurements and the alterations using the same procedure as above. - Fig. 6 shows the graph as it is presented by the programme. Fig. 6: Conductivity of acetic acid solutions as a function of the concentration. 4 PHYWE Systeme GmbH & Co. KG All rights reserved P

5 Conductivity of strong and weak electrolytes TEC Theory and evaluation The resistance of a conductor having a uniform cross section is proportional to the length l an inversively proportional to the cross sectional area A of the conductor. The substance constant ρ is known as the specific resistance; its reciprocal κ as the specific conductivity, and the reciprocal of the resistance as the conductance L. It is usual to use ρ for metallic conductors and κ for electrolytes. The conductivity for an electrolytic solution results in the following: having the dimension Ω -1. cm -1. If the conductivity of a solution is to be measured, then the measurements of the cell (length an area) must be known. Therefore, the cell is usually calibrated with a solution with a known conductivity. The ratio of the measured to the tabulated conductivity of a calibration solution directly provides the ratio of the length to the cross section. This ratio is also known as the cell constant. Usually it can be found in the accompanying test certificate. As a result of the strong concentration dependency, the conductivity is not appropriate for comparing electrolytes. For these purposes it is better to determine the molar conductivity Λ. This is calculated from the specific conductivity κ and the concentration c (in mol. l -1 ) of the substance in the electrolyte solution: When the concentration dependence of the conductivity in electrolytes is examined, one finds that the conductivity basically increases with the concentration because the number of the charge carriers (ions) increases. The plot of molar conductivity versus concentration can be calculated with by setting the parameters as given in Fig. 7. In this operation you can also substract the conductivity of the distilled water. The two diagrams for potassium chloride and acetic acid are shown in Fig. 8. Fig. 7: Parameters of channel modification. P PHYWE Systeme GmbH & Co. KG All rights reserved 5

6 TEC Conductivity of strong and weak electrolytes Fig. 8: Molar conductivities of aqueous potassium chloride and acetic acid solutions as functions of the concentration. The molar conductivity approaches a limit Λ with increasing dilution. This is the conductivity at infinite dilution. Kohlrausch found the following conformity to natural law for the concentration dependency of the molar conductivity for strong electrolytes: According to Kohlrausch s law, plotting the molar conductivity of KCl against the square root of the concentration should result in a straight line. This line s intersection with the ordinate is the molar conductivity at infinite dilution. Weak electrolytes do not dissociate completely and have a lower conductivity than strong electrolytes. As the concentration increases, the dissociation equilibrium shifts in the direction of non-dissociated molecules. The degree of dissociation α of weak electrolytes is the quotient of the molar conductivity divided by the molar conductivity at infinite dilution. Ostwald s dilution law is valid for weak electrolytes. It enables dissociation constants to be calculated: The limiting value of the molar conductivity of weak electrolytes at infinite dilution is first reached at extremely low concentrations; therefore, exact measurements in this are no longer possible. Consequently Λ cannot be obtained by extrapolating Λ m / c 0.5 -curves for weak electrolytes. The following equation is derived by transforming Ostwald s law of dilution: 6 PHYWE Systeme GmbH & Co. KG All rights reserved P

7 Conductivity of strong and weak electrolytes TEC From this equation it can be seen that a linear relationship exists between the reciprocal of the conductivity and the product of the molar conductivity and the concentration of weak electrolytes. Furthermore, Ostwald s law of dilution shows that the molar conductivity at infinite dilution can be obtained from the line s point of intersection of the line with the ordinate 1 / Λ m over c. Λ m. Disposal The diluted solutions of potassium chloride and acetic acid can be disposed by rinsing into the drain. Appendix Hazard symbol, signal word Potassium chloride Hazard statements Precautionary statements Acetic acid Danger H226: Flammable liquid and vapour. H314: Causes severe skin burns and eye damage. P280: Wear protective gloves/protective clothing/eye protection/face protection. P : IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do. continue rinsing. P310: Immediately call a POISON CENTER or doctor/physician. P PHYWE Systeme GmbH & Co. KG All rights reserved 7

8 TEC Conductivity of strong and weak electrolytes Room for notes 8 PHYWE Systeme GmbH & Co. KG All rights reserved P

Determination of the enthalpy of combustion using a bomb calorimeter TEC. Safety precautions

Determination of the enthalpy of combustion using a bomb calorimeter TEC. Safety precautions Safety precautions Naphthalene is harmful if swallowed. May cause cancer. Is further very toxic to aquatic organisms and can have long-term harmful effects in bodies of water. Equipment 1 Bomb calorimeter

More information

18 Conductometric Titration

18 Conductometric Titration Lab Activity 18 CONDUCTOMETRIC TITRATION LAB ACTIVITY 18 Conductometric Titration Background Titration is the a method of determining the concentration of an unknown solution (the analyte) by reacting

More information

Acid Base Titrations

Acid Base Titrations Acid Base Titrations Introduction A common question chemists have to answer is how much of something is present in a sample or a product. If the product contains an acid or base, this question is usually

More information

Determination of the enthalpy of combustion using a bomb calorimeter TEC

Determination of the enthalpy of combustion using a bomb calorimeter TEC Determination of the enthalpy of TEC Related concepts First law of thermodynamics, Hess s law of constant heat summation, enthalpy of combustion, enthalpy of formation, heat capacity. Principle The bomb

More information

9. Analysis of an Acid-Base Titration Curve: The Gran Plot

9. Analysis of an Acid-Base Titration Curve: The Gran Plot 9. Analysis of an Acid-Base Titration Curve: The Gran Plot In this experiment, you will titrate a sample of pure potassium hydrogen phthalate (Table 10-4) with standard NaOH. A Gran plot will be used to

More information

ph units constitute a scale which allows scientists to determine the acid or base content of a substance or solution. The ph 0

ph units constitute a scale which allows scientists to determine the acid or base content of a substance or solution. The ph 0 ACID-BASE TITRATION LAB PH 2.PALM INTRODUCTION Acids and bases represent a major class of chemical substances. We encounter them every day as we eat, clean our homes and ourselves, and perform many other

More information

Determining the Quantity of Iron in a Vitamin Tablet. Evaluation copy

Determining the Quantity of Iron in a Vitamin Tablet. Evaluation copy Determining the Quantity of Iron in a Vitamin Tablet Computer 34 As biochemical research becomes more sophisticated, we are learning more about the role of metallic elements in the human body. For example,

More information

15. Acid-Base Titration. Discover the concentration of an unknown acid solution using acid-base titration.

15. Acid-Base Titration. Discover the concentration of an unknown acid solution using acid-base titration. S HIFT INTO NEUTRAL 15. Acid-Base Titration Shift into Neutral Student Instruction Sheet Challenge Discover the concentration of an unknown acid solution using acid-base titration. Equipment and Materials

More information

DETERMINATION OF PHOSPHORIC ACID CONTENT IN SOFT DRINKS

DETERMINATION OF PHOSPHORIC ACID CONTENT IN SOFT DRINKS DETERMINATION OF PHOSPHORIC ACID CONTENT IN SOFT DRINKS LAB PH 8 From Chemistry with Calculators, Vernier Software & Technology, 2000 INTRODUCTION Phosphoric acid is one of several weak acids that present

More information

Direct ISE Method Method 8359 10 to 1000 mg/l Na + Sodium ISE

Direct ISE Method Method 8359 10 to 1000 mg/l Na + Sodium ISE Sodium DOC316.53.01240 Direct ISE Method Method 8359 10 to 1000 mg/l Na + Sodium ISE Scope and application: For drinking water and process water. Test preparation Instrument-specific information This procedure

More information

Evaluation copy. Titration of a Diprotic Acid: Identifying an Unknown. Computer

Evaluation copy. Titration of a Diprotic Acid: Identifying an Unknown. Computer Titration of a Diprotic Acid: Identifying an Unknown Computer 25 A diprotic acid is an acid that yields two H + ions per acid molecule. Examples of diprotic acids are sulfuric acid, H 2 SO 4, and carbonic

More information

Determining the Identity of an Unknown Weak Acid

Determining the Identity of an Unknown Weak Acid Purpose The purpose of this experiment is to observe and measure a weak acid neutralization and determine the identity of an unknown acid by titration. Introduction The purpose of this exercise is to identify

More information

Electrical Conductivity of Aqueous Solutions

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,.

More information

Acid-Base Titration. Evaluation copy. Figure 1

Acid-Base Titration. Evaluation copy. Figure 1 Acid-Base Titration Computer 24 A titration is a process used to determine the volume of a solution needed to react with a given amount of another substance. In this experiment, you will titrate hydrochloric

More information

Harmonic oscillation springs linked in parallel and in series

Harmonic oscillation springs linked in parallel and in series Harmonic oscillation TEP Principle The spring constant k for different springs and connections of springs is determined. For different experimental set-ups and suspended mass the oscillation period is

More information

TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS

TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS Adapted from "Chemistry with Computers" Vernier Software, Portland OR, 1997 INTRODUCTION Titration is the volumetric measurement of a solution

More information

6 H2O + 6 CO 2 (g) + energy

6 H2O + 6 CO 2 (g) + energy AEROBIC RESPIRATION LAB DO 2.CALC From Biology with Calculators, Vernier Software & Technology, 2000. INTRODUCTION Aerobic cellular respiration is the process of converting the chemical energy of organic

More information

Determining the Mole Ratios in a Chemical Reaction

Determining the Mole Ratios in a Chemical Reaction Determining the Mole Ratios in a Chemical Reaction Computer 9 A balanced chemical reaction equation gives the mole ratios of the reactants and the products as coefficients. When some of the chemical formulas

More information

Turn in your graphs and pages 9-12 ONLY

Turn in your graphs and pages 9-12 ONLY CHEM 152 WINTER 2010 POTENTIOMETRIC TITRATIONS Fill-in, Prelab attached (p 12) Name Turn in your graphs and pages 9-12 ONLY LEARNING OBJECTIVES: After completing this experiment, you should feel comfortable:

More information

Lab 5: Quantitative Analysis- Phosphates in Water By: A Generous Student. LBS 171L Section 9 TA: Dana October 27, 2005

Lab 5: Quantitative Analysis- Phosphates in Water By: A Generous Student. LBS 171L Section 9 TA: Dana October 27, 2005 How uch Phosphate is the Body Being Exposed to During a Lifetime by Showering? Lab 5: Quantitative Analysis- Phosphates in Water By: A Generous Student LBS 171L Section 9 TA: Dana October 7, 005 [Note:

More information

Liquid Conductivity: Measuring Conductivity in Saline Water Solutions (Teacher s Guide)

Liquid Conductivity: Measuring Conductivity in Saline Water Solutions (Teacher s Guide) Liquid Conductivity: Measuring Conductivity in Saline Water Solutions (Teacher s Guide) OVERVIEW Students measure the conductivity of a solution of distilled water with varying amounts of NaCl and will

More information

Lab 25. Acid-Base Titration and Neutralization Reactions: What Is the Concentration of Acetic Acid in Each Sample of Vinegar?

Lab 25. Acid-Base Titration and Neutralization Reactions: What Is the Concentration of Acetic Acid in Each Sample of Vinegar? Lab 25. Acid-Base Titration and Neutralization Reactions: What Is the Concentration of Acetic Acid in Each Sample of Vinegar? Introduction Vinegar is basically a solution of acetic acid (CH3COOH). It is

More information

Electrochemistry Revised 04/29/15

Electrochemistry Revised 04/29/15 INTRODUCTION TO ELECTROCHEMISTRY: CURRENT, VOLTAGE, BATTERIES, & THE NERNST EQUATION Experiment partially adapted from J. Chem. Educ., 2008, 85 (8), p 1116 Introduction Electrochemical cell In this experiment,

More information

AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2+

AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2+ AP Chemistry Laboratory #16: Determination of the Equilibrium Constant of FeSCN 2 Lab day: Wednesday, February 12, 2014 Lab due: Wednesday, February 19, 2014 Goal (list in your lab book): The goal of this

More information

Chem 1B Saddleback College Dr. White 1. Experiment 8 Titration Curve for a Monoprotic Acid

Chem 1B Saddleback College Dr. White 1. Experiment 8 Titration Curve for a Monoprotic Acid Chem 1B Saddleback College Dr. White 1 Experiment 8 Titration Curve for a Monoprotic Acid Objectives To learn the difference between titration curves involving a strong acid with a strong base and a weak

More information

Conductivity and Chemical Reactions

Conductivity and Chemical Reactions Experiment 5 Conductivity and Chemical Reactions Prepared by Ross S. Nord, Eastern Michigan University PURPOSE A conductivity probe will be used to identify different types of electrolytes. The relationship

More information

Experiment 13: Determination of Molecular Weight by Freezing Point Depression

Experiment 13: Determination of Molecular Weight by Freezing Point Depression 1 Experiment 13: Determination of Molecular Weight by Freezing Point Depression Objective: In this experiment, you will determine the molecular weight of a compound by measuring the freezing point of a

More information

ChE 203 - Physicochemical Systems Laboratory EXPERIMENT 7: CONDUCTOMETRIC AND POTENTIOMETRIC TITRATIONS

ChE 203 - Physicochemical Systems Laboratory EXPERIMENT 7: CONDUCTOMETRIC AND POTENTIOMETRIC TITRATIONS ChE 203 - Physicochemical Systems Laboratory EXPERIMENT 7: CONDUCTOMETRIC AND POTENTIOMETRIC TITRATIONS Before the experiment: Read the booklet carefully. Be aware of the safety issues. a. CONDUCTOMETRIC

More information

ph: Measurement and Uses

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

More information

Acid Dissociation Constants and the Titration of a Weak Acid

Acid Dissociation Constants and the Titration of a Weak Acid Acid Dissociation Constants and the Titration of a Weak Acid One of the most important applications of equilibria is the chemistry of acids and bases. The Br√łnsted-Lowry acid-base theory defines an acid

More information

ph Measurements of Common Substances

ph Measurements of Common Substances Chem 100 Section Experiment 10 Name Partner s Name Introduction ph Measurements of Common Substances The concentration of an acid or base is frequently expressed as ph. Historically, ph stands for the

More information

Nitrogen, Ammonia. Known Addition ISE Method 1 Method 10002 Minimum of 0.8 mg/l NH 3 N. Ammonia ISE. Test preparation. Instrument-specific table

Nitrogen, Ammonia. Known Addition ISE Method 1 Method 10002 Minimum of 0.8 mg/l NH 3 N. Ammonia ISE. Test preparation. Instrument-specific table Nitrogen, Ammonia DOC316.53.01234 Known Addition ISE Method 1 Method 10002 Minimum of 0.8 mg/l NH 3 N Scope and application: For wastewater 2. Ammonia ISE 1 Adapted from the Standard Methods for the Examination

More information

ph and Acidity in Wine and Fruit Juice

ph and Acidity in Wine and Fruit Juice ph and Acidity in Wine and Fruit Juice DOC316.52.93089 Endpoint potentiometric titration Scope and application: Wine and fruit juice 1. Introduction This working procedure refers to the titration of total

More information

Enzyme Action: Testing Catalase Activity

Enzyme Action: Testing Catalase Activity Enzyme Action: Testing Catalase Activity Experiment 6A Many organisms can decompose hydrogen peroxide (H 2 O 2 ) enzymatically. Enzymes are globular proteins, responsible for most of the chemical activities

More information

Colligative Properties: Freezing Point Depression and Molecular Weight

Colligative Properties: Freezing Point Depression and Molecular Weight Purpose: Colligative Properties: Freezing Point Depression and Molecular Weight The first purpose of this lab is to experimentally determine the van't Hoff (i) factor for two different substances, sucrose

More information

ph Measurement and its Applications

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,

More information

Determination of a Chemical Formula

Determination of a Chemical Formula 1 Determination of a Chemical Formula Introduction Molar Ratios Elements combine in fixed ratios to form compounds. For example, consider the compound TiCl 4 (titanium chloride). Each molecule of TiCl

More information

Titration of Hydrochloric Acid with Sodium Hydroxide

Titration of Hydrochloric Acid with Sodium Hydroxide Cautions: Hydrochloric acid solution is a strong acid. Sodium hydroxide solution is a strong base. Both are harmful to skin and eyes. Affected areas should be washed thoroughly with copious amounts of

More information

Determination of the Identity of an Unknown Weak Acid

Determination of the Identity of an Unknown Weak Acid Determination of the Identity of an Unknown Weak Acid Adapted from R. C. Kerber et. al http://www.sinc.sunysb.edu/class/orgolab/che199_susb014.pdf; W.F. Kinard et.al http://www.cofc.edu/~kinard/221lchem/2002chem221labschedule.htm;

More information

Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1

Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1 Experiment 10 Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1 E10-2 The task The goal of this experiment is to determine accurately the concentration of acetic acid in vinegar via volumetric

More information

CHEM 43303. The Oxidation of Formic Acid by Bromine

CHEM 43303. The Oxidation of Formic Acid by Bromine CHEM 43303 Experiment No. 01 The Oxidation of Formic Acid by Bromine 1. Introduction Bromine oxidises formic (methanoic) acid to carbon dioxide according to the following stoichiometric equation HCOOH

More information

Lab #11: Determination of a Chemical Equilibrium Constant

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

More information

EXPERIMENT INTRODUCTION TO INDICATORS AND ACID-BASE TITRATIONS

EXPERIMENT INTRODUCTION TO INDICATORS AND ACID-BASE TITRATIONS EXPERIMENT INTRODUCTION TO INDICATORS AND ACID-BASE TITRATIONS By Dale A. Hammond, PhD, Brigham Young University Hawaii LEARNING OBJECTIVES The objectives of this experiment are... an introduction to ph

More information

The Determination of an Equilibrium Constant

The Determination of an Equilibrium Constant The Determination of an Equilibrium Constant Computer 10 Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium

More information

The introduction of your report should be written on the on the topic of the role of indicators on acid base titrations.

The introduction of your report should be written on the on the topic of the role of indicators on acid base titrations. Experiment # 13A TITRATIONS INTRODUCTION: This experiment will be written as a formal report and has several parts: Experiment 13 A: Basic methods (accuracy and precision) (a) To standardize a base (~

More information

Properties of Acids and Bases

Properties of Acids and Bases Lab 22 Properties of Acids and Bases TN Standard 4.2: The student will investigate the characteristics of acids and bases. Have you ever brushed your teeth and then drank a glass of orange juice? What

More information

To calibrate a ph probe. To become familiar with acid-base titration curves. To determine the concentration of an unknown acid.

To calibrate a ph probe. To become familiar with acid-base titration curves. To determine the concentration of an unknown acid. Experiment 7 Titration Curves of Strong and Weak Acids and Bases To calibrate a ph probe. To become familiar with acid-base titration curves. To determine the concentration of an unknown acid. Goals Equipment

More information

Acid Base Titration: ph Titration Curve

Acid Base Titration: ph Titration Curve Acid Base Titration: ph Titration Curve OVERVIEW In this experiment, you will perform a ph-monitored titration of acetic acid and of an unknown acid. From the ph titration of the acetic acid, you will

More information

CONDUCTIVITY SENSOR. Description D0382. Figure 1. The Conductivity Sensor

CONDUCTIVITY SENSOR. Description D0382. Figure 1. The Conductivity Sensor CONDUCTIVITY SENSOR Description D0382 Figure 1. The Conductivity Sensor Short Description The Conductivity Sensor can be used to measure either solution conductivity or total ion concentration of aqueous

More information

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)

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

More information

Colligative Properties - Freezing Point Depression

Colligative Properties - Freezing Point Depression Purpose To observe freezing point depression of different solutions and calculate the molar mass of commercial antifreeze. Introduction In winter, trucks dispense dirt and salt onto the roads and antifreeze

More information

ph Measurement and Control

ph Measurement and Control ph Measurement and Control Tech Tip #14 1997 I. The Need for ph II. ph System Requirements III. ph Electrode Conditioning Procedures IV. How the electrode works V. Identifying the Electrode Components

More information

Experiment 17: Potentiometric Titration

Experiment 17: Potentiometric Titration 1 Experiment 17: Potentiometric Titration Objective: In this experiment, you will use a ph meter to follow the course of acid-base titrations. From the resulting titration curves, you will determine the

More information

Household Acids and Bases

Household Acids and Bases Household Acids and Bases GRADE LEVEL INDICATORS Experiment Demonstrate that the ph scale (0-14) is used to measure acidity and classify substances or solutions as acidic, basic, or neutral. 21 Develop

More information

Enzyme Action: Testing Catalase Activity

Enzyme Action: Testing Catalase Activity Enzyme Action: Testing Catalase Activity Experiment 6A Many organisms can decompose hydrogen peroxide (H 2 O 2 ) enzymatically. Enzymes are globular proteins, responsible for most of the chemical activities

More information

Colorimetric Determination of Iron in Vitamin Tablets

Colorimetric Determination of Iron in Vitamin Tablets Cautions: 6 M hydrochloric acid is corrosive. Purpose: To colorimetrically determine the mass of iron present in commercial vitamin tablets using a prepared calibration curve. Introduction: Iron is considered

More information

Figure 1. A voltaic cell Cu,Cu 2+ Ag +, Ag. gas is, by convention, assigned a reduction potential of 0.00 V.

Figure 1. A voltaic cell Cu,Cu 2+ Ag +, Ag. gas is, by convention, assigned a reduction potential of 0.00 V. Voltaic Cells Introduction In this lab you will first prepare a set of simple standard half-cells and then measure the voltage between the half-cells with a voltmeter. From this data you will be able to

More information

1. To perform a potentiometric titration of a sample of Liquid Drano with hydrochloric acid.

1. To perform a potentiometric titration of a sample of Liquid Drano with hydrochloric acid. INTRODUCTION ANALYSIS OF DRAIN CLEANER (Revised: 1-25-93) Many common household cleaners contain acids or bases. Acidic cleaners, such as toilet bowl cleaners, often contain hydrochloric acid or sodium

More information

Neutralization Reactions. Evaluation copy

Neutralization Reactions. Evaluation copy Neutralization Reactions Computer 6 If an acid is added to a base, a chemical reaction called neutralization occurs. An example is the reaction between nitric acid, HNO 3, and the base potassium hydroxide,

More information

Accurately Diluting a Solution

Accurately Diluting a Solution Accurately Diluting a Solution Correct Use of Volumetric Transfer Pipettes Dr. David C. Stone 2005-2006 Department of Chemistry, University of Toronto All rights reserved. This is a print version of the

More information

Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution

Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution OBJECTIVES 1. To illustrate the use of calorimetry in the experimental measurement of thermodynamic data. 2. To illustrate

More information

A 21 a - Whey Protein Nitrogen Index

A 21 a - Whey Protein Nitrogen Index A 21 a - Whey Protein Nitrogen Index GEA Niro Method No. A 21 a Revised: November 2009 1. Principle The undenaturated Whey Protein Nitrogen Index (WPN) is a measure of the heat treatment applied to the

More information

Experiment 6 Titration II Acid Dissociation Constant

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

More information

Synthesis, Isolation, and Purification of an Ester

Synthesis, Isolation, and Purification of an Ester Synthesis, Isolation, and Purification of an Ester AP Chemistry Laboratory Introduction An ester is a chemical compound that is formed when an organic acid reacts with an alcohol. Esters frequently have

More information

DENSITY OF AQUEOUS SODIUM CHLORIDE SOLUTIONS

DENSITY OF AQUEOUS SODIUM CHLORIDE SOLUTIONS Experiment 3 DENSITY OF AQUEOUS SODIUM CHLORIDE SOLUTIONS Prepared by Ross S. Nord and Stephen E. Schullery, Eastern Michigan University PURPOSE Determine the concentration of an unknown sodium chloride

More information

ANALYSIS OF WATER FOR CHLORIDE AND SULFATE IONS

ANALYSIS OF WATER FOR CHLORIDE AND SULFATE IONS Test Procedure for ANALYSIS OF WATER FOR CHLORIDE AND SULFATE IONS TxDOT Designation: Tex-619-J Effective Date: August 2005 1. SCOPE 1.1 Use this method to analyze water for chloride and sulfate ions to

More information

experiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration.

experiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration. 81 experiment5 LECTURE AND LAB SKILLS EMPHASIZED Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. Determining percent yield. Learning how to perform a vacuum

More information

EXPERIMENT 12: Empirical Formula of a Compound

EXPERIMENT 12: Empirical Formula of a Compound EXPERIMENT 12: Empirical Formula of a Compound INTRODUCTION Chemical formulas indicate the composition of compounds. A formula that gives only the simplest ratio of the relative number of atoms in a compound

More information

Pressure -Temperature Relationship in Gases. Evaluation copy. Figure 1. 125 ml Erlenmeyer flask. Vernier computer interface

Pressure -Temperature Relationship in Gases. Evaluation copy. Figure 1. 125 ml Erlenmeyer flask. Vernier computer interface Pressure -Temperature Relationship in Gases Computer 7 Gases are made up of molecules that are in constant motion and exert pressure when they collide with the walls of their container. The velocity and

More information

Potentiometry: The ph Electrode and Potentiometric Titrations

Potentiometry: The ph Electrode and Potentiometric Titrations Potentiometry: The ph Electrode and Potentiometric Titrations In this experiment you will investigate the Nernstian response of a ph electrode, perform potentiometric titrations, investigate the acid-base

More information

A Soaked Potato Nancy C. Griffin

A Soaked Potato Nancy C. Griffin 4.27-1 SCIENCE EXPERIMENTS ON FILE Revised Edition A Soaked Potato Nancy C. Griffin Topic Osmosis Time 10 minutes preparation; 2 days to completion! Safety Please click on the safety icon to view the safety

More information

MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1

MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1 MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry EXPERIMENT #5 THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1 I. PURPOSE OF THE EXPERIMENT In this experiment

More information

Purification by Recrystallization

Purification by Recrystallization Experiment 2 Purification by Recrystallization Objectives 1) To be able to select an appropriate recrystallizing solvent. 2) To separate and purify acetanilide by recrystallization. 3) To compare the melting

More information

ANALYSIS of DRAIN CLEANERS WITH a ph METER

ANALYSIS of DRAIN CLEANERS WITH a ph METER ANALYSIS of DRAIN CLEANERS WITH a ph METER LAB PH 3 From Juniata College SIM INTRODUCTION Most common household cleaners contain acids or bases. Acidic cleaners, such as toilet bowl cleaners, often contain

More information

Molar Mass of Polyvinyl Alcohol by Viscosity

Molar Mass of Polyvinyl Alcohol by Viscosity Molar Mass of Polyvinyl Alcohol by Viscosity Introduction Polyvinyl Alcohol (PVOH) is a linear polymer (i. e., it has little branching) of Ethanol monomer units: -CH 2 -CHOH- Unlike most high molar mass

More information

ACIDS AND BASES SAFETY PRECAUTIONS

ACIDS AND BASES SAFETY PRECAUTIONS ACIDS AND BASES Mild acids and bases are used in cooking (their reaction makes biscuits and bread rise). Acids such as those in our stomachs eat away at food or digest it. Strong acids and bases are used

More information

ph and Acidity in Tomato Sauce

ph and Acidity in Tomato Sauce ph and Acidity in Tomato Sauce DOC316.52.93100 Endpoint potentiometric titration Scope and application: Tomato sauce 1. Introduction This working procedure refers to the determination of titratable acidity

More information

Freezing Point Depression, the van t Hoff Factor, and Molar Mass

Freezing Point Depression, the van t Hoff Factor, and Molar Mass , the van t Hoff Factor, and Molar Mass Objectives To understand colligative properties. To find the freezing point depression of a solution. To determine the van't Hoff factor for acetic acid dissolved

More information

DETERMINING SULFATE CONTENT IN SOILS COLORIMETRIC METHOD

DETERMINING SULFATE CONTENT IN SOILS COLORIMETRIC METHOD Test Procedure for DETERMINING SULFATE CONTENT IN SOILS COLORIMETRIC TxDOT Designation: Tex-145-E Effective Date: February 2005 1. SCOPE 1.1 This method determines the soluble sulfate content of soil by

More information

5s Solubility & Conductivity

5s Solubility & Conductivity 5s Solubility & Conductivity OBJECTIVES To explore the relationship between the structures of common household substances and the kinds of solvents in which they dissolve. To demonstrate the ionic nature

More information

Hydrogen Peroxide Analysis

Hydrogen Peroxide Analysis elearning 2009 Introduction Hydrogen Peroxide Analysis Consumer Chemistry Publication No. 91253 Hydrogen peroxide is regarded as an environmentally friendly alternative to chlorine for water purification

More information

Determination of the amount of sodium carbonate and sodium hydroxide in a mixture by titration.

Determination of the amount of sodium carbonate and sodium hydroxide in a mixture by titration. Module 9 : Experiments in Chemistry Lecture 38 : Titrations : Acid-Base, Redox and Complexometric Objectives In this lecture you will learn the techniques to do following Determination of the amount of

More information

In this experiment, we will use three properties to identify a liquid substance: solubility, density and boiling point..

In this experiment, we will use three properties to identify a liquid substance: solubility, density and boiling point.. Identification of a Substance by Physical Properties 2009 by David A. Katz. All rights reserved. Permission for academic use provided the original copyright is included Every substance has a unique set

More information

To determine the equivalence points of two titrations from plots of ph versus ml of titrant added.

To determine the equivalence points of two titrations from plots of ph versus ml of titrant added. Titration Curves PURPOSE To determine the equivalence points of two titrations from plots of ph versus ml of titrant added. GOALS 1 To gain experience performing acid-base titrations with a ph meter. 2

More information

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

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

More information

For the highest level of protection, safety goggles that completely cover the. seal against the face are recommended.

For the highest level of protection, safety goggles that completely cover the. seal against the face are recommended. Lab Equipment Safety Goggles For the highest level of protection, safety goggles that completely cover the eye and eye socket and seal against the face are recommended. Lab Apron (folded) Beaker Beakers

More information

Practical 1: Measure the molar volume of a gas

Practical 1: Measure the molar volume of a gas Practical Student sheet Practical : Wear eye protection. Ensure the delivery tube does not become blocked. Ethanoic acid will sting if it gets into cuts in the skin. Equipment boiling tube stand and clamp

More information

Lab 9. Colligative Properties an Online Lab Activity

Lab 9. Colligative Properties an Online Lab Activity Prelab Assignment Before coming to lab: Lab 9. Colligative Properties an Online Lab Activity Chemistry 162 - K. Marr Revised Winter 2014 This lab exercise does not require a report in your lab notebook.

More information

Measuring ph in Water or CaCl2 Using a ph Meter. Compiled by Darren Murray, June 30, 2011 TABLE OF CONTENTS OVERVIEW 3

Measuring ph in Water or CaCl2 Using a ph Meter. Compiled by Darren Murray, June 30, 2011 TABLE OF CONTENTS OVERVIEW 3 Measuring ph in Water or CaCl2 Using a ph Meter Compiled by Darren Murray, June 30, 2011 TABLE OF CONTENTS OVERVIEW 3 PREPARING THE ph METER FOR USE (Calibration and Buffer Solutions) 4 When is Calibration

More information

The Boltzmann Distribution Lee Marek

The Boltzmann Distribution Lee Marek 5.27-1 SCIENCE EXPERIMENTS ON FILE Revised Edition The Boltzmann Distribution Lee Marek Topic Distribution of kinetic energy Time 30 minutes! Safety Please click on the safety icon to view the safety precautions.

More information

DETERMINING THE MASS OF A COPPER ATOM

DETERMINING THE MASS OF A COPPER ATOM DETERMINING THE MASS OF A COPPER ATOM LAB ADV.31 From Vernier Software & Technology, 2004 STANDARDS ADDRESSED 3.4.10 A Explains concepts about the structure and properties of matter. 3.4.12 A Apply concepts

More information

Milwaukee USER MANUAL

Milwaukee USER MANUAL Milwaukee USER MANUAL PORTABLE DISSOLVED OXYGEN METER MODEL: MW600 Smart DO Meter PROBE PREPARATION: The meter is supplied with a 9V battery. Slide off the battery compartment cover on the back of the

More information

USEPA Electrode Method Method 8156

USEPA Electrode Method Method 8156 ph DOC316.53.01245 USEPA Electrode Method Method 8156 Scope and application: For drinking water 1, wastewater 2 and process water. 1 Based on Standard Method 4500-H+B, ASTM Method D1293-95 and USEPA Method

More information

SOLUBILITY, IONIC STRENGTH AND ACTIVITY COEFFICIENTS

SOLUBILITY, IONIC STRENGTH AND ACTIVITY COEFFICIENTS SOLUBILITY, IONIC STRENGTH AND ACTIVITY COEFFICIENTS References: 1. See `References to Experiments' for text references.. W. C. Wise and C. W. Davies, J. Chem. Soc., 73 (1938), "The Conductivity of Calcium

More information

EXPERIMENT 7 Electrochemical Cells: A Discovery Exercise 1. Introduction. Discussion

EXPERIMENT 7 Electrochemical Cells: A Discovery Exercise 1. Introduction. Discussion EXPERIMENT 7 Electrochemical Cells: A Discovery Exercise 1 Introduction This lab is designed for you to discover the properties of electrochemical cells. It requires little previous knowledge of electrochemical

More information

Experiment 12- Classification of Matter Experiment

Experiment 12- Classification of Matter Experiment Experiment 12- Classification of Matter Experiment Matter can be classified into two groups: mixtures and pure substances. Mixtures are the most common form of matter and consist of mixtures of pure substances.

More information

Experiment 3 Limiting Reactants

Experiment 3 Limiting Reactants 3-1 Experiment 3 Limiting Reactants Introduction: Most chemical reactions require two or more reactants. Typically, one of the reactants is used up before the other, at which time the reaction stops. The

More information

Evaluation copy. Enzyme Action: Testing Catalase Activity (Method 1 O 2 Gas Sensor) Computer 2

Evaluation copy. Enzyme Action: Testing Catalase Activity (Method 1 O 2 Gas Sensor) Computer 2 Enzyme Action: Testing Catalase Activity (Method 1 O 2 Gas Sensor) Computer 2 Many organisms can decompose hydrogen peroxide (H 2 O 2 ) enzymatically. Enzymes are globular proteins, responsible for most

More information

Characteristic curves of a solar cell

Characteristic curves of a solar cell Related Topics Semi-conductor, p-n junction, energy-band diagram, Fermi characteristic energy level, diffusion potential, internal resistance, efficiency, photo-conductive effect, acceptors, donors, valence

More information

(1) Hydrochloric acid reacts with sodium hypochlorite to form hypochlorous acid: NaOCl(aq) + HCl(aq) HOCl(aq) + NaCl(aq) hypochlorous acid

(1) Hydrochloric acid reacts with sodium hypochlorite to form hypochlorous acid: NaOCl(aq) + HCl(aq) HOCl(aq) + NaCl(aq) hypochlorous acid The Determination of Hypochlorite in Bleach Reading assignment: Chang, Chemistry 10 th edition, pages 156-159. We will study an example of a redox titration in order to determine the concentration of sodium

More information