EXPERIMENT 3 THE IODINE CLOCK

Save this PDF as:

Size: px
Start display at page:

Download "EXPERIMENT 3 THE IODINE CLOCK"

Transcription

1 EXPERIMENT 3 THE IODINE CLOCK Introduction The Rates of Chemical Reactions Broadly defined, chemical kinetics is the study of the rates at which chemical reactions proceed. Oftentimes, reaction rate data helps chemists to develop reaction mechanisms for a given chemical reaction. The rate of a chemical reaction depends upon several parameters, such as temperature, pressure and the initial composition of a system undergoing a reaction. If one wishes to consider a reaction for which a balanced chemical equation is known, several reaction rates can be determined: [1] In [1], it is observed that 2A*s and 4B*s are required to produce 3C*s and one D. For dilute solutions, reaction rates can be expressed by considering the change in concentration of a particular constituent that is being consumed or produced with respect to the change in time: Reaction Rate Law and Reaction Order The rate, ν, at which a chemical reaction proceeds is often found to be proportional in some fashion to the concentration of each reactant raised to some exponential power: [2] Where a and b are experimentally determined values and k is the rate constant. The rate law is not, in general, to be inferred from a balanced chemical reaction, rather, it must be determined experimentally. The constants a and b are oftentimes integers and the overall reaction order is equal to their sum. Thus, for example, if a and b were determined to be equal to 2 and 1, respectively, the reaction is said to be third-order (a + b = = 3). Determination of the Rate Law One very popular method of determining the rate law is known as the method of initial rates, and is aptly titled as the rate is measured only for the initial stages of a chemical reaction. This method involves making a series of solutions, each with a different composition and observing the initial reaction rate as a function of the changing reactant composition. For a reaction which involves two reactive species, the general process involves first keeping the concentration of one of the reactants constant (reactant A, for example) while varying the concentration of the other (reactant B). Then, the concentration of B is held fixed while varying the concentration of A. By plotting the logarithm of the initial rate, ν 0, against the logarithm of the concentration of the reactant whose concentration is being varied, the reaction order with respect to that constituent can be determined as it is equal to the slope of a first-order line of best fit (m = a, according to [2], for the case where [A] is being varied; see Figure 3.1). 29

2 log v 0 (units of M s -1 ) log(v 0 ) = log([A]) R 2 = log [A] (units of M) Figure 3.1 Plot of log ν 0 versus log [A]. According to the line of best fit, the reaction is clearly second-order with respect to reactant A. The Iodine Clock In this lab experiment, the reaction between the persulfate ion (S 2 O 8 2 ) and the iodide ion (I ) is studied in aqueous media and may be represented by the following chemical equation: [3] Two additional reagents are used: the first provides the thiosulfate anion (S 2 O 3 2 ). This anion reacts very quickly, with respect to the process described by [3], with any iodine present: [4] Once all of the thiosulfate is consumed, the iodine being evolved at this point will react with any iodide present and their product forms a complex with the second additional reagent, which is starch. This reaction produces a purple colour which signals the end of the data sampling period. Therefore, by considering the amount of thiosulfate added to the reaction mixture, one can measure the rate of the reaction. 30

3 The Reaction Medium One should also consider the influence that the reaction medium has upon the reaction rate. The observed reaction rate is not only a function of the items outlined earlier, but is also dependent upon the solvent used (not considered in this experiment) and the ionic strength, I, of the solution. In order to determine the rate constant at infinite dilution, k 0, a correction which accounts for the ionic strength of the solution is done (note that this form of the correction is only applicable when the Debye-Hückel limiting law holds): Where z A and z B are the charge numbers associated with the two atoms or molecules that are undergoing the chemical reaction under study. The Rate Constant as a Function of Temperature The rate constant for many chemical reactions is found to increase in a linear fashion when a plot of ln k versus 1/T is composed. This is the graphical expression of the Arrhenius equation: [5] [6] where A is commonly denoted as the frequency factor and where E a is the activation energy of the reaction under consideration. Activated Complex Theory In bimolecular reactions, the two reacting species (A and B, for example) are postulated to pass through some form of transition state, which is often higher in energy than the reactants. This is the basis of activated complex theory (sometimes referred to as transition state theory). By using this theory, one can relate the rate constant to the Gibbs energy of activation, G, for a particular temperature: Where κ is the transmission coefficient, a dimensionless quantity which will be assumed to equal 1, k is the Boltzmann constant, h is the Planck constant, and H and S are the enthalpy of activation and the entropy of activation, respectively. All other parameters carry their usual meaning. For reactions carried out in solution, the enthalpy of activation is related to the activation energy: Therefore, with G and H known, S can be determined by using the equation which expresses the change in Gibbs energy for an isothermal process. [7] [8] 31

4 Materials 4 50 ml burettes 3 medium test tubes 1 test tube rack ml beakers 1 1 L beaker ml volumetric flasks ml Erlenmeyer flasks 1 hot plate & stirrer 1 water bath 1 thermometer 2 scoopula 2 magnetic stir bars 1 stopwatch ml pipette & bulb ml pipettes ammonium chloride (NH 4 Cl) potassium chloride (KCl) ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) potassium iodide (KI) sodium thiosulfate pentahydrate (Na 2 S 2 O 3 C5H 2 O ) starch solution Procedure The following solutions will be provided: M ammonium chloride (NH 4 Cl) (A1) M potassium chloride (KCl) (A2) A. Preparation of Required Solutions Prepare the following solutions using the room temperature de-ionized water (note: DO NOT use tap water for the preparation of these samples): ml of 0.05 M ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) (A3) ml of 0.12 M potassium iodide (KI) (A4) ml of ca M sodium thiosulfate pentahydrate (Na 2 S 2 O 3 C5H 2 O) (A5) 32

5 B. The Effect of Reactant Concentrations on ν 0 1. For A3 and A4, transfer some of each solution into separate 100 ml beakers and then into separate 50 ml burettes. You may wish to label the burettes so you do not mix up the solutions. 2. In a similar fashion as step B1, transfer some de-ionized water, as well as some starch solution, into 50 ml burettes. A total of four burettes should be filled with solution. 3. Prepare two solutions as indicated by the trial #1 row in the table below (do not mix them!): #1 - Into Erlenmeyer Flask #2 - Into Test Tube Trial # A1 A3 A5 H 2 O A2 A4 Starch 1 0.0* * amounts of added solution are to be taken as in units of ml 4. While the solutions for this trial are being prepared, the hot plate can be setup as depicted in Figure 3.2 and the stopwatch prepared for use. 5. Once a stable temperature has been established (do not turn the heating function on), record this temperature in your data sheet, immerse the Erlenmeyer flask into the water bath and when ready, quickly add the contents of the test tube to the flask. Start timing about halfway into adding the contents of the test tube. 6. You will notice that the solution is not coloured in any way, yet appears slightly cloudy. Stop timing when the solution is purple in colour (i.e., continue timing if it is only faintly purple). 7. After the trial, clean and dry the test tube and flask as best as you can, then transfer the items into the oven to eliminate any residual water. 8. Repeat steps as necessary until you have time measurements for all 7 trials. 33

6 test tube stand Erlenmayer flask thermometer stir bar water bath hot plate / stirrer Figure 3.2 C. The Effect of Temperature on ν 0 1. Fill the 1 L beaker about 3/4 of the way with de-ionized water. This beaker will serve as the new water bath for the remainder of this experiment. 2. Heat the bath until the temperature is around 35 EC and then remove the beaker from the heat source. Prepare the solutions using the same composition as outlined in trial #1 and hence, conduct trial #1 once again at this temperature. Record the initial temperature, the elapsed time and the final temperature (the temperature after colour change) on your data sheet. The average of the starting and final temperatures will be used as the temperature at which the trial was conducted. 3. Repeat step C2, but this time heat the bath until the temperature is around 45 EC. Calculations Part B. 1. For each trial in Part B, determine the initial concentration of all the ionic species present and tabulate your results. You might find it useful to explicitly write down all of the chemical dissociation equations. Determine the average reaction temperature. 2. Determine the initial reaction rate, ν 0, for all trials in part B. Express these rates in units of M min Create two plots, one of log ν 0 versus log [I ] using the data from trials 1 4 and one of log ν 0 versus log [S 2 O 8 2- ] using the data from trials 1 and 5 7. Fit the data using a function of the form y = mx + b. From the slope, determine the reaction order with respect to each component. Round your value to the nearest half-integer. 4. Determine the rate constant for each trial and average these values. This mean value will be known as the average rate constant at room temperature, k rt. 5. Determine the ionic strength of one of the solutions used and using equation [5], determine 34

7 the rate constant at infinite dilution, k 0, and compare this value with the literature. Assume that the Debye-Hückel limiting law holds. Part C. 1. Determine the rate constant of the experiment at the two elevated experimental temperatures. Use these two values and k rt to create a plot of ln k versus 1/T and determine E a for this reaction. Interpolate to find k 298 (i.e., the rate constant at T = 298 K). 2. Using k 298 and equations [7] and [8], determine GE and HE and comment upon the chemical significance of these values. Note: pay close attention to units when solving [7] for GE. Use these two values to determine SE and comment upon the physical meaning of the value isolated. 3. Using an appropriate reference (see list below), determine the standard Gibbs energy of reaction, r G, from the f G values associated with each reacting species. 4. Using the values determined in steps C2 and C3, sketch a Gibbs energy reaction profile as the reactants are converted into products. Lab Questions 1. Starting from the form of the rate equation given in [2], show why a plot of log ν 0 vs. log [A] would give the order of reaction with respect to that particular reactant. 2. Why were the NH 4 Cl and KCl salts used? If water were to be substituted for them, how would it affect the observed rate constant and by how much? (find the percent difference) Hint: assume the same starting composition for one of the trials where a non-reagent salt was used, but replace the added salt with water. 3. If reaction [3] is the third-order reaction, what are the units of k(t) [3]? 4. An investigator is conducting kinetic experiments on a first-order reaction A P for which the rate coefficient at 298 K is k 0 = s -1. The activation energy for the reaction is found to be 40 kj mol -1. Assume that a simple Arrhenius expression gives the dependence of k upon temperature. The investigator runs the reaction in a container whose temperature is being continuously varied such that the temperature at time t is T = (T 0 )/( t) where T 0 is the temperature at time t = 0. When half of the initial amount of A has been consumed, what is the temperature in the reaction vessel? References 1. Atkins, Peter and Julio de Paula. Physical Chemistry. 7 th ed. New York: W. H. Freeman, , , , , Bernasconi, Claude F., ed. Investigation of Rates and Mechanisms of Reactions. 4 th ed. Toronto: John Wiley & Sons, Wagman, Donald D. Selected Values of Chemical Thermodynamic Properties. Washington: National Bureau of Standards, Howells, W. J. Journal of the Chemical Society (Resumed). 1939, Amis, Edward S., and James E. Potts. J. Am Chem. Soc. 1941, 63, Moews, P.C., and R. H. Petrucci. Journal of Chemical Education. 1964, 41,

8 Data Sheet A. Concentration of NH 4 Cl solution: mol L -1 Concentration of KCl solution: mol L -1 Concentration of (NH 4 ) 2 S 2 O 8 solution: mol L -1 Concentration of KI solution: mol L -1 Concentration of Na 2 S 2 O 3 solution: mol L -1 B. Trial # Temperature (EC) Elapsed Time (m:s) Average Reaction Temperature: EC C. Trial T i (EC) T f (EC) T& (EC) Elapsed Time (m:s) ca. 35 EC ca. 45 EC 36

CHEM Experiment 1 Factors Governing the Speed of Chemical Reactions

CHEM Experiment 1 Factors Governing the Speed of Chemical Reactions CHEM 3310 Experiment 1 Factors Governing the Speed of Chemical Reactions Experiment 1: Factors Affecting Reaction Rates Part A Effect of Concentration on Reaction Rate CHEM 3310 2 Iodine clock Reaction

More information

CHEM Experiment 1. of Chemical Reactions

CHEM Experiment 1. of Chemical Reactions Experiment 1 Factors Governing the Speed of Chemical Reactions Experiment 1: Factors Affecting Reaction Rates Part A Effect of Concentration on Reaction Rate 2 Iodine clock Reaction S 2 O 8 (aq) + 2 I

More information

Experiment 2: Factors Affecting Reaction Rates

Experiment 2: Factors Affecting Reaction Rates Objective: Part A To determine the effect of concentration on the rate of formation of Iodine, I 2, and therefore, determine the reaction s rate law. Part B To study the effect of temperature on the rate

More information

Experiment 2: The Rate of an Iodine Clock Reaction

Experiment 2: The Rate of an Iodine Clock Reaction Experiment 2: The Rate of an Iodine Clock Reaction Introduction: Some reactions, including most of the ones that you have seen before, occur so rapidly that they are over as soon as the reactants are mixed.

More information

EXPERIMENT 1 REACTION RATE, RATE LAW, AND ACTIVATION ENERGY THE IODINE CLOCK REACTION

EXPERIMENT 1 REACTION RATE, RATE LAW, AND ACTIVATION ENERGY THE IODINE CLOCK REACTION PURPOSE: To determine the Rate Law and the Activation Energy for a reaction from experimental data. PRINCIPLES: The Rate Law is a mathematical expression that predicts the rate of a reaction from the concentration

More information

Lowell High School AP Chemistry Spring 2009 REACTION KINETICS EXPERIMENT

Lowell High School AP Chemistry Spring 2009 REACTION KINETICS EXPERIMENT Lowell High School AP Chemistry Spring 2009 REACTION KINETICS EXPERIMENT Complete the following for Pre-Lab on a clean sheet of paper: (1) In your own words, explain the following: a. why the I 2 concentration

More information

Kinetics of an Iodine Clock Reaction

Kinetics of an Iodine Clock Reaction Kinetics of an Iodine Clock Reaction Introduction: In this experiment, you will determine the rate law for a reaction and the effect of concentration on the rate of the reaction by studying the initial

More information

Kinetics of an Iodine Clock Reaction

Kinetics of an Iodine Clock Reaction Kinetics of an Iodine Clock Reaction Introduction: In this experiment, you will determine the rate law for a reaction and the effect of concentration on the rate of the reaction by studying the initial

More information

IODINE CLOCK REACTION KINETICS

IODINE CLOCK REACTION KINETICS Name: Section Chemistry 104 Laboratory University of Massachusetts Boston IODINE CLOCK REACTION KINETICS PRELAB ASSIGNMENT Calculate the initial concentration of H 2 O 2 that exists immediately after mixing

More information

Rate Properties of an Iodide Oxidation Reaction

Rate Properties of an Iodide Oxidation Reaction Rate Properties of an Iodide Oxidation Reaction GOAL AND OVERVIEW The rate law for the reduction reaction of peroxodisulfate (PODS) by iodide: S 2 O8 2 (aq) + 2 I (aq) I 2 (aq) + 2 SO4 2 (aq) will be determined.

More information

Rate of Reaction. Introduction

Rate of Reaction. Introduction 5 Rate of Reaction Introduction This experiment will allow you to study the effects of concentration, temperature, and catalysts on a reaction rate. The reaction whose rate you will study is the oxidation

More information

A Chemical Clock. 5. Consider each of the following questions regarding data and measurements:

A Chemical Clock. 5. Consider each of the following questions regarding data and measurements: A Chemical Clock Things to Consider 1. What are the three major objectives of this experiment? What methods will you try using to achieve each of these three objectives? 2. What is difference between reaction

More information

Determining the Rate Law for a Chemical Reaction

Determining the Rate Law for a Chemical Reaction Determining the Rate Law for a Chemical Reaction Purpose: To determine the reaction orders, rate law, and rate constant for the reaction between persulfate ions, SO8 -, and iodide ions, I - Introduction

More information

A STUDY OF REACTION RATES

A STUDY OF REACTION RATES CH095 A Study of Reaction Rates Page 1 A STUDY OF REACTION RATES Chemical reaction rates are affected by changes in concentration of the reactants and temperature. How concentration and temperature affect

More information

Thermodynamics and the Solubility of Sodium Tetraborate Decahydrate

Thermodynamics and the Solubility of Sodium Tetraborate Decahydrate Thermodynamics and the Solubility of Sodium Tetraborate Decahydrate In this experiment you, as a class, will determine the solubility of sodium tetraborate decahydrate (Na 2 B 4 O 7 10 H 2 O or Na 2 [B

More information

THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE

THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE INTRODUCTION FACTORS INFLUENCING REACTION RATE: The study of chemical reactions is not complete without a consideration of the rates at which

More information

CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric

CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric Name Team Name CHM112 Lab Iodine Clock Reaction Part 2 Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial concentrations completed

More information

Determination of the Rate Constant for an Iodine Clock Reaction

Determination of the Rate Constant for an Iodine Clock Reaction CHEM 122L General Chemistry Laboratory Revision 1.3 Determination of the Rate Constant for an Iodine Clock Reaction To learn about Integrated Rate Laws. To learn how to measure a Rate Constant. To learn

More information

Experiment 26 - Kinetics

Experiment 26 - Kinetics Chem 1B Dr. White 175 Experiment 26 - Kinetics Objectives To determine the rate law for the reaction between iodide and bromate under acidic conditions To investigate the effect of temperature on rate

More information

#5 Chemical Kinetics: Iodine Clock Reaction

#5 Chemical Kinetics: Iodine Clock Reaction #5 Chemical Kinetics: Iodine Clock Reaction In the previous experiment, we discussed the factors that influence the rate of a chemical reaction and presented the terminology used in quantitative relations

More information

PRACTICAL NUMBER 1 AN EXPERIMENT TO DETERMINE THE RATE CONSTANT AND THE REACTION ORDER FOR THE OXIDATION OF IODIDE BY PEROXODISULFATE

PRACTICAL NUMBER 1 AN EXPERIMENT TO DETERMINE THE RATE CONSTANT AND THE REACTION ORDER FOR THE OXIDATION OF IODIDE BY PEROXODISULFATE PRACTICAL NUMBER 1 AN EXPERIMENT TO DETERMINE THE RATE CONSTANT AND THE REACTION ORDER FOR THE OXIDATION OF IODIDE BY PEROXODISULFATE INTRODUCTION In this experiment you will determine the initial rate

More information

Kinetics; A Clock Reaction

Kinetics; A Clock Reaction Kinetics; A Clock Reaction Background This experiment involves the study of the rate properties, or chemical kinetics, of the following reaction between iodide ion (I - ) and bromate ion (BrO 3 - ) under

More information

Examining the Effect of Temperature on Reaction Rate

Examining the Effect of Temperature on Reaction Rate 1 Purpose: To measure reaction rate at different temperatures for the reaction between persulfate ions, S2O8-2, and iodide ions, I -, and thereby determine the activation energy and frequency factor for

More information

KINETICS II - THE IODINATION OF ACETONE Determining the Activation Energy for a Chemical Reaction

KINETICS II - THE IODINATION OF ACETONE Determining the Activation Energy for a Chemical Reaction KINETICS II - THE IODINATION OF ACETONE Determining the Activation Energy for a Chemical Reaction The rate of a chemical reaction depends on several factors: the nature of the reaction, the concentrations

More information

Investigating the Effect of Concentration on an Iodide Persulphate Reaction, and Rate Law Determination. Lab Performed on Monday, February 25 th, 2013

Investigating the Effect of Concentration on an Iodide Persulphate Reaction, and Rate Law Determination. Lab Performed on Monday, February 25 th, 2013 Investigating the Effect of Concentration on an Iodide Persulphate Reaction, and Rate aw Determination ab Performed on Monday, February 25 th, 2013 Introduction The purpose of this lab is to observe the

More information

Experiment #5. Iodine Clock Reaction Part 1

Experiment #5. Iodine Clock Reaction Part 1 Experiment #5. Iodine Clock Reaction Part 1 Introduction In this experiment you will determine the Rate Law for the following oxidation- reduction reaction: 2 H + (aq) + 2 I (aq) + H 2 O 2 (aq) I 2 (aq)

More information

CIE Chemistry A-Level Practicals for Papers 3 and 5

CIE Chemistry A-Level Practicals for Papers 3 and 5 CIE Chemistry A-Level Practicals for Papers 3 and 5 Rate of Reaction Disappearing cross: Change in rate of the reaction of sodium thiosulphate with hydrochloric acid as temperature is changed: Na 2 S 2

More information

How Do Certain Factors Affect the Rate of a Chemical Reaction?

How Do Certain Factors Affect the Rate of a Chemical Reaction? EXPERIMENT 7 How Do Certain Factors Affect the Rate of a Chemical Reaction? INTRODUCTION Two important questions may be asked about a chemical reaction. () How completely do the reactants combine to give

More information

CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric

CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric Name Team Name CHM112 Lab Iodine Clock Reaction Part 1 Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Initial concentrations completed

More information

EXPERIMENT 7- SAPONIFICATION RATE OF TERT- BUTYL CHLORIDE

EXPERIMENT 7- SAPONIFICATION RATE OF TERT- BUTYL CHLORIDE 1 THEORY EXPERIMENT 7- SAPONIFICATION RATE OF TERT- BUTYL CHLORIDE The field of chemical kinetics is concerned with the rate or speed at which a chemical reaction occurs. Knowledge of a chemical reaction

More information

Experimental Procedure Lab 402

Experimental Procedure Lab 402 Experimental Procedure Lab 402 Overview Measured volume of several solutions having known concentrations of reactants are mixed in a series of trials. The time required for a visible color change to appear

More information

PRACTICAL NUMBER 1 AN INVESTIGATION OF THE EFFECT OF CHANGING CONCEN- TRATION ON THE RATE OF OXIDATION OF IODIDE BY PER- OXODISULFATE

PRACTICAL NUMBER 1 AN INVESTIGATION OF THE EFFECT OF CHANGING CONCEN- TRATION ON THE RATE OF OXIDATION OF IODIDE BY PER- OXODISULFATE PRACTICAL NUMBER 1 AN INVESTIGATION OF THE EFFECT OF CHANGING CONCEN- TRATION ON THE RATE OF OXIDATION OF IODIDE BY PER- OXODISULFATE INTRODUCTION In this experiment you will determine the initial rate

More information

EXPERIMENT 2 DETERMINATION OF K a USING THE CONDUCTANCE METHOD

EXPERIMENT 2 DETERMINATION OF K a USING THE CONDUCTANCE METHOD EXPERIMENT 2 DETERMINATION OF K a USING THE CONDUCTANCE METHOD Introduction Equilibrium Processes When a pure sample of liquid-state acetic acid (i.e., CH 3 COOH (l) /HAc (l) ) is added to a beaker of

More information

Iodine Clock Part I Chemical Kinetics

Iodine Clock Part I Chemical Kinetics Collect: Iodine Clock Part I Chemical Kinetics (2015/11/17 revised) 50 ml Erlenmeyer flask (10): wash clean, dry, and cool 5 ml graduated pipet (2), pipet filler (1) Cork stopper (6) Stopwatch (1) (given

More information

UNIT 2: KINETICS RATES of Chemical Reactions (TEXT: Chap 13-pg 573)

UNIT 2: KINETICS RATES of Chemical Reactions (TEXT: Chap 13-pg 573) UNIT 2: KINETICS RATES of Chemical Reactions (TEXT: Chap 13-pg 573) UNIT 2: LAB 1. A Brief Introductory Kinetics Investigation A) Set up 4 test tubes containing about 5 ml of 0.1 M sodium oxalate sol n.

More information

AP CHEMISTRY LAB RATES OF CHEMICAL REACTIONS (II)

AP CHEMISTRY LAB RATES OF CHEMICAL REACTIONS (II) PURPOSE: Observe a redox reaction. AP CHEMISTRY LAB RATES OF CHEMICAL REACTIONS (II) Apply graphing techniques to analyze data. Practice computer skills to develop a data table. Determine the order of

More information

The Kinetics of the Iodine Clock Reaction

The Kinetics of the Iodine Clock Reaction Experiment 2 Pre-lab Assignment Before coming to lab: Read the lab thoroughly. Answer the pre-lab questions that appear at the end of this lab exercise. The questions should be answered on a separate (new)

More information

Exp.3 Determination of the Thermodynamic functions for the Borax Solution

Exp.3 Determination of the Thermodynamic functions for the Borax Solution Exp.3 Determination of the Thermodynamic functions for the Borax Solution Theory: The relationship between Gibb s energy (ΔG), Enthalpy (ΔH), Entropy (ΔS) and the equilibrium constant (K) for a chemical

More information

15. Determination of the order of the reaction between hydrogen peroxide and iodide ions in the presence of sulphuric acid Student Sheet

15. Determination of the order of the reaction between hydrogen peroxide and iodide ions in the presence of sulphuric acid Student Sheet 15. Determination of the order of the reaction between hydrogen peroxide and iodide ions in the presence of sulphuric acid Student Sheet Intended lesson outcomes By the end of this exercise you should

More information

PURPOSE: To determine the Rate Law for the following chemical reaction:

PURPOSE: To determine the Rate Law for the following chemical reaction: PURPOSE: To determine the Rate Law for the following chemical reaction: H 2 O 2 (aq) + 2 I - (aq) + 2 H 3 O + (aq) 4 H 2 O(l) + I 2 (aq) Hydrogen Iodide Hydronium Water Iodine Peroxide Ion Ion PRINCIPLES:

More information

DETERMINING AND USING H

DETERMINING AND USING H DETERMINING AND USING H INTRODUCTION CHANGES IN CHEMISTRY Chemistry is the science that studies matter and the changes it undergoes. Changes are divided into two categories: physical and chemical. During

More information

Partner: Judy 29 March Analysis of a Commercial Bleach

Partner: Judy 29 March Analysis of a Commercial Bleach Partner: Judy 29 March 2012 Analysis of a Commercial Bleach Purpose: The purpose of this lab is to determine the amount of sodium hypochlorite (NaClO) in commercial bleach. This can be done by forming

More information

RESEARCH ARTICLE The Kinetics of Oxidation of Iodide ion by Dichromate Ion in an Acidic Medium

RESEARCH ARTICLE The Kinetics of Oxidation of Iodide ion by Dichromate Ion in an Acidic Medium International Journal of Advanced Chemical Research Vol. 4, No. 10, PP. 044-048, October 2015 http://www.wrpjournals.com/ijacr RESEARCH ARTICLE The Kinetics of Oxidation of Iodide ion by Dichromate Ion

More information

EXPERIMENT C3: SOLUBILITY PRODUCT & COMMON ION EFFECT. Learning Outcomes. Introduction. Upon completion of this lab, the student will be able to:

EXPERIMENT C3: SOLUBILITY PRODUCT & COMMON ION EFFECT. Learning Outcomes. Introduction. Upon completion of this lab, the student will be able to: 1 EXPERIMENT C3: SOLUBILITY PRODUCT & COMMON ION EFFECT Learning Outcomes Upon completion of this lab, the student will be able to: 1) Measure the solubility product constant for a sparingly soluble salt.

More information

Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7

Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7 Name: Section: Score: /10 PRE LABORATORY ASSIGNMENT EXPERIMENT 7 1. Is the sign of Δ r H for an exothermic reaction positive or negative? Why? 2. When 4.21 grams of potassium hydroxide are added to 250.

More information

Lab Activity 3: Factors Affecting Reaction Rate

Lab Activity 3: Factors Affecting Reaction Rate Chemistry 3202 Lab #3 factors affecting Reaction Rate Page 1 of 5 Lab Activity 3: Factors Affecting Reaction Rate Introduction Several factors influence how fast a reaction proceeds. In this activity,

More information

Chemical Kinetics. Reaction rate and activation energy of the acid hydrolysis of ethyl acetate LEC 05. What you need: What you can learn about

Chemical Kinetics. Reaction rate and activation energy of the acid hydrolysis of ethyl acetate LEC 05. What you need: What you can learn about LEC 05 Chemical Kinetics Reaction rate and activation energy of the acid hydrolysis What you can learn about Reaction rate Rate law for first and second order reactions Reactions with pseudo-order Arrhenius

More information

CHEM 254 EXPERIMENT 5. Solubility and Enthalpy of Fusion of Ammonium Oxalate in Water

CHEM 254 EXPERIMENT 5. Solubility and Enthalpy of Fusion of Ammonium Oxalate in Water CHEM 254 EXPERIMENT 5 Solubility and Enthalpy of Fusion of Ammonium Oxalate in Water In general solubility (g/100 ml) is defined as amount of substance that dissolved in a given solvent at a given temperature.

More information

The Thermodynamics of the Solubility of Borax

The Thermodynamics of the Solubility of Borax Experiment 10 Pre-Lab Assignment Before coming to lab: Read the lab thoroughly. Answer the pre-lab questions that appear at the end of this lab exercise. The questions should be answered on a separate

More information

A Clock Reaction: Determination of the Rate Law for a Reaction

A Clock Reaction: Determination of the Rate Law for a Reaction 1 A Clock Reaction: Determination of the Rate Law for a Reaction This experiment involves the study of the rate properties, or chemical kinetics, of the following reaction between iodide ion and bromate

More information

Thermodynamics of Borax Dissolution

Thermodynamics of Borax Dissolution Thermodynamics of Borax Dissolution Introduction In this experiment, you will determine the values of H, G and S for the reaction which occurs when borax (sodium tetraborate octahydrate) dissolves in water.

More information

ACTIVATION ENERGY OF IODINATION OF ACETONE

ACTIVATION ENERGY OF IODINATION OF ACETONE ACTIVATION ENERGY OF IODINATION OF ACETONE Investigating the effect of temperature on the rate of Iodination of Acetone, and hence determining the Activation energy of the reaction. 0 1 CONTENTS Introduction:...

More information

Experiment 4: Rates of Chemical Reactions II: Kinetic Study of the Reaction between Ferric and Iodine Ions

Experiment 4: Rates of Chemical Reactions II: Kinetic Study of the Reaction between Ferric and Iodine Ions Experiment 4: Rates of Chemical Reactions II: Kinetic Study of the Reaction between Ferric and Iodine Ions PURPOSE: To study kinetics of the reaction between ferric (Fe 3+ ) and iodide (I - ) ions, i.e.

More information

EXPERIMENT: LIMITING REAGENT. NOTE: Students should have moles of reactants in DATASHEET converted into masses in grams prior to the lab period.

EXPERIMENT: LIMITING REAGENT. NOTE: Students should have moles of reactants in DATASHEET converted into masses in grams prior to the lab period. Revised 12/2015 EXPERIMENT: LIMITING REAGENT Chem 1104 Lab NOTE: Students should have moles of reactants in DATASHEET converted into masses in grams prior to the lab period. INTRODUCTION Limiting reactant

More information

EXPERIMENT A4: PRECIPITATION REACTION AND THE LIMITING REAGENT. Learning Outcomes. Introduction

EXPERIMENT A4: PRECIPITATION REACTION AND THE LIMITING REAGENT. Learning Outcomes. Introduction 1 EXPERIMENT A4: PRECIPITATION REACTION AND THE LIMITING REAGENT Learning Outcomes Upon completion of this lab, the student will be able to: 1) Demonstrate the formation of a precipitate in a chemical

More information

Suggested answers to in-text activities and unit-end exercises. Topic 16 Unit 55

Suggested answers to in-text activities and unit-end exercises. Topic 16 Unit 55 Suggested answers to in-text activities and unit-end exercises In-text activities Discussion (page 117) Some possible ways for minimizing possible sources of error in the experiment: Add a slight excess

More information

Experiment 2: Analysis of Commercial Bleach Solutions

Experiment 2: Analysis of Commercial Bleach Solutions Experiment 2: Analysis of Commercial Bleach Solutions I. Introduction The ability of household bleach to remove stains is related to the amount of oxidizing agent in it. The oxidizing agent in bleach is

More information

Electrochemistry. To use principles of electrochemistry to understand the properties of electrochemical cells and electrolysis.

Electrochemistry. To use principles of electrochemistry to understand the properties of electrochemical cells and electrolysis. Electrochemistry Objectives: To use principles of electrochemistry to understand the properties of electrochemical cells and electrolysis. Background: Part I: Galvanic Cells: A Galvanic cell is a device

More information

(g) burns according to this reaction? D) CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O(l)

(g) burns according to this reaction? D) CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O(l) Name: 7171-1 - Page 1 1) In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is defined as the A) heat of reaction B) ionization

More information

Safety Note: Safety glasses and laboratory coats are required when performing this experiment

Safety Note: Safety glasses and laboratory coats are required when performing this experiment The Determination of Hypochlorite in Bleach Reading assignment: Burdge, Chemistry 4 th edition, section 4.6. We will study an example of a redox titration in order to determine the concentration of sodium

More information

Set 4 Marking Scheme: Acid Bases & Salts 2010

Set 4 Marking Scheme: Acid Bases & Salts 2010 Set 4 Marking Scheme: Acid Bases & Salts 00 ACID AND BASES PAPER : STRUCTURE (a) Neutralisation KOH + H SO 4 K SO 4 + H O Correct formulae of reactants and products Balanced equation i. H +, OH -, K +

More information

Determination of Reducing Sugar Content: Clinitest, Benedict s Solution and the Rebelein Titration

Determination of Reducing Sugar Content: Clinitest, Benedict s Solution and the Rebelein Titration Determination of Reducing Sugar Content: Clinitest, Benedict s Solution and the Rebelein Titration Chemical Concepts and Techniques: The most important sugars present in wine and fruit juice are the hexoses

More information

THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER V010516

THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER V010516 THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER V010516 OBJECTIVE The ΔG, ΔH and ΔS of the potassium nitrate (KNO3) dissolving reaction will be determined by measuring the equilibrium constant

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

Measuring Enthalpy Changes

Measuring Enthalpy Changes Measuring Enthalpy Changes PURPOSE To observe changes in enthalpy in chemical processes. GOALS To identify exothermic and endothermic processes. To relate enthalpy changes and entropy changes to changes

More information

PRACTICAL 3 ph AND BUFFERS

PRACTICAL 3 ph AND BUFFERS PRACTICAL 3 ph AND BUFFERS ph and Buffers Structure 3.1 Introduction 3.2 ph and Buffers: Basic Concept 3.2.1 ph 3.2.2 Buffers and Buffer Solutions 3.3 Methods for Determining ph Experiment 1: Measurement

More information

Kinetics of an Iodine Clock Reaction Lab_Student Copy

Kinetics of an Iodine Clock Reaction Lab_Student Copy Kinetics of an Iodine Clock Reaction Lab_Student Copy Purpose: Purpose: In this lab, you will find the reaction rate, rate law,, and observe the effects of a catalyst for the oxidation of iodide ions by

More information

Kinetics of an Iodine Clock Reaction Lab_ Teacher s Key

Kinetics of an Iodine Clock Reaction Lab_ Teacher s Key Kinetics of an Iodine Clock Reaction Lab_ Teacher s Key Purpose: In this lab, you will find the reaction rate, rate law,, and observe the effects of a catalyst for the oxidation of iodide ions by bromate

More information

THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE

THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE THE EFFECT OF TEMPERATURE AND CONCENTRATION ON REACTION RATE INTRODUCTION FACTORS INFLUENCING REACTION RATE: The study of chemical reactions is not complete without a consideration of the rates at which

More information

Chem 116 POGIL Worksheet - Week 6 Kinetics - Part 2

Chem 116 POGIL Worksheet - Week 6 Kinetics - Part 2 Chem 116 POGIL Worksheet - Week 6 Kinetics - Part 2 Why? A different form of the rate law for a reaction allows us to calculate amounts as a function of time. One variation on this gives us the concept

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *9763634822* CHEMISTRY 9701/36 Paper 3 Advanced Practical Skills 2 October/November 2014 2 hours Candidates

More information

Le Chatelier s Principle

Le Chatelier s Principle Le Chatelier s Principle Introduction: In this experiment you will observe shifts in equilibrium systems when conditions such as concentration and temperature are changed. You will explain the observed

More information

Chemistry 1B Experiment 17 89

Chemistry 1B Experiment 17 89 Chemistry 1B Experiment 17 89 17 Thermodynamics of Borax Solubility Introduction In this experiment, you will determine the values of H and S for the reaction which occurs when borax (sodium tetraborate

More information

The thermodynamics of the solubility of borax

The thermodynamics of the solubility of borax Chemistry 1 6 3 The thermodynamics of the solubility of borax Purpose: To determine the thermodynamic quantities ΔH and ΔS for the solvation reaction of borax in water by measuring the solubility product

More information

The remaining questions were developed by John Gelder.

The remaining questions were developed by John Gelder. 1.Design an experiment to collect data that supports the claim that a 1.0 M NaCl solution is a homogeneous mixture. Describe the steps, the data you would collect, and how the data support the claim. Laboratory

More information

THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER 1

THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER 1 THE THERMODYNAMICS OF POTASSIUM NITRATE DISSOLVING IN WATER 1 OBJECTIVE In this experiment, the changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of the potassium nitrate (KNO 3 ) dissolving

More information

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level CHEMISTRY 9701/31 Paper 3 Advanced Practical Skills 1 May/June 2014 2 hours Candidates answer on the

More information

Annex 2 Formaldehyde

Annex 2 Formaldehyde Annex 2 Formaldehyde The 2 methods are analytical procedures for the determination of formaldehyde CH2O, PM/Ref. No 17260, and hexamethylenetetramine (HMTA) C6H12N4, PM/Ref. No 18670, in food simulants

More information

Experiment 2: Reaction Stoichiometry by Thermometric Titration

Experiment 2: Reaction Stoichiometry by Thermometric Titration Experiment 2: Reaction Stoichiometry by Thermometric Titration Introduction The net result of a reaction (a chemical change) is summarized by a chemical equation. In order to write a chemical equation,

More information

Chem 116 POGIL Worksheet - Week 6 Kinetics - Concluded

Chem 116 POGIL Worksheet - Week 6 Kinetics - Concluded Chem 116 POGIL Worksheet - Week 6 Kinetics - Concluded Why? The half-life idea is most useful in conjunction with first-order kinetics, which include many chemical reactions and all nuclear decay processes.

More information

Determination of the K a of a Weak Acid and the K b of a Weak Base from ph Measurements

Determination of the K a of a Weak Acid and the K b of a Weak Base from ph Measurements Experiment 6 Determination of the K a of a Weak Acid and the K b of a Weak Base from ph Measurements Pre-Lab Assignment Before coming to lab: Read the lab thoroughly. Answer the pre-lab questions that

More information

SOLVOLYSIS OF tert-butyl CHLORIDE: TESTING A MECHANISM

SOLVOLYSIS OF tert-butyl CHLORIDE: TESTING A MECHANISM SOLVOLYSIS OF tert-butyl CHLORIDE: TESTING A MECHANISM Organic chemists are keenly interested in how and why chemical reactions occur. They propose a plausible mechanism for a given reaction, then do experiments

More information

Experiment Eight Acids and Bases

Experiment Eight Acids and Bases Name: Lab Section: Experiment Eight Acids and Bases Objective Identifying and understanding the nature of acids and bases is an important part of the laboratory toolbox, the purpose of this lab is to help

More information

#30 Thermochemistry: Heat of Solution

#30 Thermochemistry: Heat of Solution #30 Thermochemistry: Heat of Solution Purpose: You will mix different salts with water and note any change in temperature. Measurements using beakers will be compared to measurements using polystyrene

More information

Equilibrium and Ionic Strength Effects

Equilibrium and Ionic Strength Effects Equilibrium and Ionic Strength Effects Objectives You will determine the thermodynamic equilibrium constant for the reaction between iron(iii) ion and thiocyanate ion to form iron(iii)-thiocyanate. Fe

More information

GE 6163 CHEMISTRY LAB MANUAL

GE 6163 CHEMISTRY LAB MANUAL VALLIAMMAI ENGINEERING COLLEGE S.R.M NAGAR, KATTANKULATHUR 603 203 Department of Chemistry (2015-2016) GE 6163 CHEMISTRY LAB MANUAL Step I : Standardization of sodium thiosulphate Titration I (Standard

More information

Experiment 5. Heat and Temperature

Experiment 5. Heat and Temperature Experiment 5 Heat and Temperature This coffee isn t hot enough! E5-1 E5-2 The Task In this experiment you will study the heat flow associated with a range of processes and examine the relationship between

More information

Name Page 1. N a m e F o rm u l a Soluble in Wa t e r? BaSO 4. Li 2 CO 3. Cu(OH) 2

Name Page 1. N a m e F o rm u l a Soluble in Wa t e r? BaSO 4. Li 2 CO 3. Cu(OH) 2 Name Page 1 AQUEOUS SOLUTIONS 1. (10 points) Names, formulas, and solubility of compounds. N a m e F o rm u l a Soluble in Wa t e r? Ammonium chloride NH 4 Cl Yes BaS Barium phosphate Manganese(IV) oxide

More information

IB Chemistry Solutions Gasses and Energy

IB Chemistry Solutions Gasses and Energy Solutions A solution is a homogeneous mixture it looks like one substance. An aqueous solution will be a clear mixture with only one visible phase. Be careful with the definitions of clear and colourless.

More information

AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) Figure 1

AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) Figure 1 www.pedersenscience.com AP Chemistry Lab #10- Hand Warmer Design Challenge (Big Idea 5) 5.A.2: The process of kinetic energy transfer at the particulate scale is referred to in this course as heat transfer,

More information

Stoichiometry Lab Final this is not a proper title, so change it to be more descriptive

Stoichiometry Lab Final this is not a proper title, so change it to be more descriptive Stoichiometry Lab Final this is not a proper title, so change it to be more descriptive Abstract **All parts of the lab must be included in this lab report (except HYPOTHESIS)** Background Discuss titrations

More information

Reaction Rate and Equilibrium Chapter 19 Assignment & Problem Set

Reaction Rate and Equilibrium Chapter 19 Assignment & Problem Set Reaction Rate and Equilibrium Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Reaction Rate and Equilibrium 2 Study Guide: Things You Must Know

More information

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level

Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *7333871663* CHEMISTRY 9701/35 Paper 3 Advanced Practical Skills 1 May/June 2015 2 hours Candidates answer

More information

Electrochemistry. Conductivity of strong and weak electrolytes LEC 06. What you need: What you can learn about. Principle and tasks

Electrochemistry. Conductivity of strong and weak electrolytes LEC 06. What you need: What you can learn about. Principle and tasks LEC 06 Electrochemistry What you can learn about Kohlrausch s law Equivalent conductivity Temperature-dependence of conductivity Ostwald s dilution law Principle and tasks It is possible to differentiate

More information

KAKAMEGA NORTH SUBCOUNTY JOINT EXAMINATIONS KCSE TRIAL 2018

KAKAMEGA NORTH SUBCOUNTY JOINT EXAMINATIONS KCSE TRIAL 2018 1 Name:... Index No:. Candidate s signature Date KAKAMEGA NORTH SUBCOUNTY JOINT EXAMINATIONS KCSE TRIAL 2018 233/3 CHEMISTRY PAPER 3 (Practical) JULY 2018 2¼ Hours INSTRUCTIONS: Write your name and index

More information

(a) What name is given to this method? (1) (b) Which piece of apparatus should be used to measure the 25.0cm 3 of KOH?

(a) What name is given to this method? (1) (b) Which piece of apparatus should be used to measure the 25.0cm 3 of KOH? 1 This apparatus can be used in a method to find the volume of sulfuric acid required to neutralise a solution of potassium hydroxide (KOH). burette containing 0.100mol/dm 3 H 2 SO 4 conical flask 25.0cm

More information

INSTRUCTOR RESOURCES

INSTRUCTOR RESOURCES Kinetic Studies of the Ferroin Complex INSTRUCTOR RESOURCES The CCLI Initiative Learning Objectives The purpose of this experiment is to... to determine the rate of a chemical reaction. to determine the

More information

Use this dramatic iodine clock reaction to demonstrate the effect of concentration, temperature, and a catalyst on the rate of a chemical reaction.

Use this dramatic iodine clock reaction to demonstrate the effect of concentration, temperature, and a catalyst on the rate of a chemical reaction. Clock Reaction Race Reaction Pathways SCIENTIFIC Introduction Use this dramatic iodine clock reaction to demonstrate the effect of concentration temperature and a catalyst on the rate of a chemical reaction.

More information

A general statement governing all systems in a state of dynamic equilibrium follows:

A general statement governing all systems in a state of dynamic equilibrium follows: Chapter 20 Experiment: LeChâtelier s Principle: Buffers OBJECTIVES: Study the effects of concentration and temperature changes on the position of equilibrium in a chemical system. Study the effect of strong

More information