Investigating the Effect of Concentration on an Iodide Persulphate Reaction, and Rate Law Determination. Lab Performed on Monday, February 25 th, 2013
|
|
- Dinah Holmes
- 6 years ago
- Views:
Transcription
1 Investigating the Effect of Concentration on an Iodide Persulphate Reaction, and Rate aw Determination ab Performed on Monday, February 25 th, 2013
2 Introduction The purpose of this lab is to observe the effect of concentration on reaction rates, to ultimately determine the rate law for the reaction between the iodide ion (I - ) and the persulphate ion (S 2 O 8 ). The general reaction can be described as (NH 4 ) 2 S 2 O 8(aq) + 2KI (aq) I 2(aq) + 2K 2 SO 4(aq) However, we know that in aqueous solution, the ions will dissociate (except for iodine) into their ionic components. The ions that are not a part of the actual reaction do not affect the ionic compounds in any ways, as they are unreactive. The reaction can be rewritten as: S 2 O 8 (aq) + 2I - (aq) I 2(aq) + 2SO 4 (aq) In this experiment, the experimenters are interested in using the rate of oxidation of the iodide ion by the persulphate ion to determine the rate law for this reaction. The rate of reaction between the two ions will be measured near the beginning of the reaction, before the concentrations of the components in the system have changed significantly. New trials will be run such that one concentration of a specie is altered from that of the original reaction, and the rate will be measured once again. To determine the reaction rate, the amount of product formed or reactant used within a time interval must be measured. For this experiment, the time required for a specific amount of diiodine (I 2 ) to be produced will be measured. To monitor when a specific amount of diiodine has been produced, the diiodine will have to react with a thiosulphate ion. I 2 (aq) + 2S 2 O 3 (aq) 2I - (aq) + S 4 O 6 (aq) As long as thiosulphate ions are still present in the aqueous solution as the reaction proceeds, the reaction will remain colourless (in the presence of starch) since the thiosulphate ions will be using up the diiodine molecules. According to the chemical reaction formula, two moles of thiosulphate is required to react with one mole of diiodine. The first appearance of free diiodine is detected by its reaction with starch. This means that the initial amount of thiosulphate ions added into the reaction has been used up, so there is nothing for the diiodine molecules to react with other than starch. The reaction between diiodine and starch will yield a violet/dark-blue colour due to the starch-iodine complex formed. The reaction should be timed from the moment the two solutions are mixed together to the moment a violet/dark-blue colour is visible. Therefore, the amount of iodine produced within this time interval will be known since the amount of thiosulphate used is known. The process of thiosulphate ions reducing iodine back to iodide before the iodine can form its complex with starch to yield a violet colour is called a clock reaction because this process is used to clock the reaction between persulphate and iodide. 2 S 2 O 3 Average Rate of the Reaction= 1 2 To determine the order of reaction with respect to the iodide ion, the concentration of persulphate must remain constant as the concentration of iodide ion varies (evine, 2002). The relationship between the change of concentration of iodide ion to the time it takes for a constant amount of thiosulphate to be used up will aid the experimenters in determining the order of the reaction with respect to I -. (evine, 2002). 2
3 In the primary iodide persulphate reaction, we are dealing with two negative ions. This means that the ionic strength of the reaction must be considered when determining the rate of reaction or rate law because the rate of reaction increases as the ionic strength of the reaction increases. The reaction rate constant therefore is dependent on the ionic strength of the reaction (on top of temperature, pressure and other various conditions), so it is necessary to maintain a constant ionic strength throughout this can be done by adding an electrolyte such as (NH 4 ) 2 SO 4 or KNO 3. The equation for calculating ionic strength is as follows: μ= 1 where C i is the molar concentration 2 2 C i Z i of the i th species, and Z i is its ionic charge. The ionic strength is a measure of the overall concentration of the ions (evine, 2002). The ionic strength of a solution decreases as the concentration of ions decrease and their valence or charge decreases (Gillenwater, 2002). Experimenters will use their experimental data to observe the relationship between reactant/product concentrations and the reaction rate to deduce the rate law of the reaction between the iodide ion and persulphate ion. Materials The materials used for this experiment is outlined in the CHEM 123 lab manual, Experiment #1. All materials were used without deviation. Experimental Procedure The experimental procedure used for this experiment is outlined in the CHEM 123 lab manual, Experiment #1. The actual experiment deviates from the experimental procedure such that only 6 runs were performed instead 7 runs. Experimental Observations Table 1: Original Observations Preparation of Stock Solutions (NH4)2S2O82 (0.100M) KI (0.200M) Na2S2O3 (0.0100M) Mass of Solid Added (+/- 0.01g) Volume of dh2o added (m) Run # Table 2: Qualitative Observations Rate Measurements using Varying Concentrations of Reactant and Product Add to Erlenmeyer 0.1M (NH 4 ) 2 S 2 O 8 m 0.1M (NH 4 ) 2 SO 4 m 0.2M KI m 0.2M KNO 3 m Add to Beaker 0.01M Na 2 S 2 O 3 m H2O m 0.2% Starch m Elapsed Time : : :08 3
4 : : : :00 Results and Calculations Below shows a table indicating all of the results and calculations for runs #1-7 Run # [S2O8] [I-] [S2O3] S2O8 t Rate ([ S2O8]/s) Rate Constant (k) Ionic Strength : : : : : : : Note: calculations will be sample calculations from trial #1 for the concentrations of S 2 O 8, I -,S 2 O 3 and - S 2 O 8 Note: Total volume in reaction vessel for all trials is 55m Calculating the Concentration of S 2 O 8 Using 20m of 0.1M (NH 4 ) 2 S 2 O 8(aq) in trial #1 V 1 C 1 =V 2 C 2 (20m) (0.1M)=(55m)C 2 C 2 =0.0364M Therefore the concentration of S 2 O 8 (aq) in trial #1 was M. Calculating the Concentration of I - Using 20m of 0.2M KI (aq) in trial #1 V 1 C 1 =V 2 C 2 (20m) (0.2M)=(55m)C 2 4
5 C 2 =0.0727M Therefore the concentration of KI (aq) in trial #1 was M. Calculating the Concentration of S 2 O 3 Using 10m of 0.01M Na 2 S 2 O 3(aq) in trial #1 V 1 C 1 =V 2 C 2 (10m) (0.01M)=(55m)C 2 C 2 = M Calculating the Change in Concentration of S 2 O 8 from the start of the reaction to when a violent/darkblue complex is formed - S 2 O 8 can be calculated by dividing the initial concentration of thiosulphate (S 2 O 3 ) by two because two moles of thiosulphate are used up per mole of iodine. This is evident in the chemical equation below. I 2 (aq) + 2S 2 O 3 (aq) 2I - (aq) + S 4 O 6 (aq) The amount of iodine produced will be half the amount of thiosulphate ions added. The amount of iodine produced is also indicative of the amount of S 2 O 8 left in the reaction vessel (1:1), which will enable us to calculate the change in concentration of S 2 O 8. Moles of thiosulphate Added Moles of Iodine Produce d= moles Moles of Iodine Produced = Moles of Persulphate Ions Produced S 2 O 8 2 = ( ) S 2 O 8 2 = moles Calculating the Time it took for the Reaction to use up all the Thiosulfate Ions For trial #1, t = 9:27 minutes = 567s Calculating the Rate of the Reaction (for Trial #2) To calculate the rate of the reaction, the rate of consumption of persulphate ions must be calculated. To do this, the change in concentration of persulphate ions (S 2 O 8 ) will be divided by the time it took for the reaction to use up all the thiosulphate ions ( t), which is essentially the time it takes for the reaction to produce a certain amount of iodine, which in turn gives the time it takes for a certain amount of persulphate ions to be converted into products ( S 2 O 8 ). 5
6 Rateof Reaction= S 2O M 567s M/ s t Calculating the Rate Constant (k) I Rate= S O 2 8 t 2 =k[s 2 O 8 2 ] m k = rate constant m = order of the reaction with respect to S 2 O 8 n = order of the reaction with respect to I - To find the value of m, a graph of log( t) vs. log[s 2 O 8 ] will be plotted, using values from runs 1, 2, 3. From the graph, the slope will be calculated, and from there, the order of the reaction with respect to S 2 O 8 can be determined. The equation for the linear trendline of this data is y=1.0651x Therefore, the order of the reaction with respect to S 2 O 8 is 1, first order. m = 1, indicating that the slope is To find the value of m, a graph of log( t) vs. log[i - ] will be plotted, using values from runs 1, 4, 5. From the graph, the slope will be calculated, and from there, the order of the reaction with respect to I - can be determined. The equation for the linear trendline of this data is y=0.8665x Therefore, the order of the reaction with respect to I - is 1, first order. I Rate= S O 2 8 t 2 =k[s 2 O 8 2 ] m n = 1, indicating that the slope is Rate for trial #2 = mol - s -, m = 1, n = 1 6
7 I Rate=k[ S 2 O 8 2 ] m mol 1 mol =k [ s ] [ mol 1 ] mol mol2 =k [ ] s 2 k = k= mol s Calculating the Ionic Strength for the Solution (for Trial #2) ionic strength=μ= 1 2 C i Z i 2 μ= 1 2 ( [ NH 4 ] (+1 ) 2 )+([ S 2 O 8 ] ( 2) 2 )+ ([ K ] (+1 ) 2 )+ ([ I ] ( 1) 2 )+([ Na ] (+1) 2 )+( [S 2 O 3 ] ( 2 ) 2 ) μ= 1 2 ([ ] (+1 )2) + ([ ] ( 2 )2 )+( [ ] (+1 ) 2 )+ ([ ] ( 1 ) 2 )+( [ ] (+1 ) 2 )+( [ Questions 1. (a.) Calculating the average rate constant for this reaction using data from trials 1 to 5. Average Rate Constant= = = (b.) The rate constant values from trials 6 and 7 are not used when calculating the average rate constant, because in the solutions made for trials 6 and 7, the species added into the beaker (which is essentially the amount of iodide ions added into the solution) is diluted with 10m and 15m of water respectively. This means that there is less iodide to be reacted with the persulphate ions. 2. (a.) k-value for run #2 = k-value for run #6 = The k-value for run #2 is larger than that for run #6 by There is a difference between these two values because in run #2, 10m of (NH 4 ) 2 SO 4(aq) was added to the Erlenmeyer flask, whereas in run #6, no volume of (NH 4 ) 2 SO 4(aq) was added. The significance of adding (NH 4 ) 2 SO 4(aq) into the reaction mixture is that we are adding the conjugate base of (NH 4 ) 2S2O8(aq) in it. This means that in run #2, since the 7
8 conjugate base is already added, less amount of (NH 4 ) 2 S 2 O 8(aq) will have to convert into (NH 4 ) 2 SO 4(aq) on the contrary in run #6, since none of the conjugate base was added initially, more (NH 4 ) 2 S 2 O 8(aq) will have to convert into (NH 4 ) 2 SO 4(aq). This will result in larger rate constant for run #2 since there will be some concentration of conjugate base to divide by the persulphate acid. (b.) k-value for run #5 = k-value for run #7 = The k-value for run #5 is larger than that for run #7 by There is a difference between these two values because in run #7, 15m of water is added to the reaction mixture, meaning that everything is diluted, whereas in run #5, no volume of water was added. Diluting the reaction with water means that the reaction will occur less rapidly since the concentration of all the species will be lowered in the presence of water volume as a result, the rate of reaction will be slower, and the rate constant will be smaller as well. This is evident as the rate constant in run #5 is and in run #7 is The rate constant for run #5 is larger as a of less diluted reactants. One factor that affects the rate of reaction, and in turn the rate constant, is the concentration of reactants or products. The higher the concentration, the more particles are able to collide, and thus will result in a quicker rate of reaction. 3. (a.) If the concentration of thiosulphate was doubled, keeping all other factors the same, there would be no effect on the actual reaction itself because thiosulphate in this case is just acting as an indicator for starch. The more concentration of thiosulphate added in the iodide-persulphate reaction, the more time it will take for a violet/dark-blue colour to appear in the solution since there are more thiosulphate ions that can react with the iodine ions. The rate of reaction would be unchanged. (b.) If the concentration of persulphate ions was halved, keeping all other factors the same, the rate of reaction would decrease by half since there are less persulphate ions per liter to react with the iodine ions and since the concentration of persulphate is first order with respect to the whole reaction. Specifically, the rate of reaction would be half of its original value. However, the rate constant will remain unchanged because the same reactants are being used. (c.) If the temperature of the solution was increased, both the rate of reaction and rate constant would increase. The rate of reaction will increase as temperature increases because having a higher temperature correlates to an increase in the average kinetic energy of the reacting system. Having a higher kinetic energy means that a greater portion of the particles will have enough energy to overcome the barrier (activation energy), and thus more reactants will be readily able to convert into products. The rate constant would increase with a temperature increase as well because the rate constant is dependent on the temperature of the system. This can be seen in Arrhenius s equation a formula for the temperature dependence of reaction rates. E a RT k=ae 8
9 where k is the rate constant, A is the exponential factor, E a is the activation energy, R is the gas constant and T is the temperature in Kelvin. This means that the rate constant changes with respect to any temperature change. 4. (a.) If the concentration of thiosulphate was doubled, keeping all other factors the same, there would be no effect on the rate constant of the reaction because the rate constant is only dependent on the temperature of the environment, ionic strength of the solution and activation energy of the reaction. (b.) If the concentration of iodine ions was halved, keeping all other factors the same, there would be no effect on the rate constant because the rate constant is only dependent on the temperature, activation energy and ionic strength of the reacting solution. The rate constant is only concerned with the orders of different reactants with respect to the reaction. A decrease in persulphate ions will only decrease the number of collisions with iodine per unit time, thus changing the rate of reaction. The rate constant is unchanged. (c.) If the ionic strength of the solution was decreased, the rate constant would decrease as well. The ionic strength of a solution is measure of the strength of the negative ions involved a solution influencing the rate of reaction. As the concentration of negative ions in a solution increases, the ionic (negative charge) decreases as well because the positive ions (spectator ions) that travel around in sync with the negative ions are present, which shields part of the negative charge. If the ionic strength of the solution was decreased, that would mean there is a greater concentration of one of the two ions or both. Decreasing the ionic strength of a solution would decrease the rate constant by increasing the effective activation energy. Discussion Why we used different runs to find m and n Reacting different concentrations of persulphate ions and iodine ions, and observing their different rates of reactions, the rate law for the iodide-persulphate reaction could be deduced as being: 2 S 2 O 8 I Rate aw=k To determine the reaction rate, the amount of product formed or reactant used within a time interval must be measured. For this experiment, the time required for a specific amount of diiodine (I 2 ) to be produced will be measured. Thiosulphate ions, which will be added to this solution will form a little reaction between itself and the iodine product molecules of the original reaction that is being tested. Thiosulphate will act like an indicator for starch in such a way that 2 moles of thiosulphate ions will consume an iodine molecule, and once all the thiosulphate ions have been used, then the starch will start binding to the iodine molecules to yield a violet/dark-blue colour in solution. If we time the reaction from when all the species are mixed to together until a change in colour is visible, we will be able to find the rate of the reaction with respect to how many iodine molecules have been produced. Once the amount of iodine molecules produced is known, the amount of persulphate ions that have been consumed into products will be known from the chemical equation of : S 2 O 8 (aq) + 2I - (aq) I 2(aq) + 2SO 4 (aq) It can be seen from the stoichiometric coefficients that for every iodine molecule (I 2 ) produced, one persulphate ion (S 2 O 8 ) is consumed (1:1 ratio). This means that the rate of reaction can be easily determined for this reaction if thiosulphate is used. 9
10 To find m, the order of the persulphate ion concentration with respect to the rate of the reaction, only data from runs 1, 2 and 3 were used. The reason for this is because to find the order with respect to one reactant, that specific reactant concentration must vary while all the other species are held constant. In runs 1, 2 and 3, the concentration of iodide ions was held constant, while the concentration for persulphate ions were varying (with its conjugate base of sulfuric acid). When -log t was plotted against log[s 2 O 8 ], the data yielded a linear regression of slope Rounding the slope to the nearest whole number as 1 was indicative of the order of the reaction with respect to the persulphate ion. Persulphate ions being first order means that the rate of reaction is directly proportional to the concentration of persulphate ions if the concentration was doubled, the rate of reaction would double as well. To find n, the order of the iodide ion concentration with respect ot he rate of the reaction, only data from runs 1, 4, 5 were used because in these trials, the concentration of persulphate ions was held constant while the concentration of the iodide ions varied. When -log t was plotted against log[i - ], the data yielded a linear regression of slope Rounding the slope to the nearest whole number as 1 was indicative of the order of the reaction with respect to the iodide ion. Iodide ions being first order also means that the rate of reaction is directly proportional to the concentration of iodide ions. The rate law for the iodide-persulphate reaction was found from one source: 2 S 2 O 8 I Rate aw= (The Rate of an Iodine Clock Reaction) From this rate law above, it shows that the value of k is , which is different than the experimentally k-value found from this experiment being (average of k-values from runs #1-7) 0.o0115. experimental value theoretical value Percentage Error= theoretical value 100 Percentage Error= Percentage error=71.25 Comparing our experimentally determined k-value to the one found from another source reveals that these 2 values have a 71.25% error. This is a large discrepancy, meaning that there were definitely some errors that were made during this lab. Another factor like temperature could have been the cause of the discrepancy. However, the orders of each reactant seem to agree with each other. In this experiment, the idea of using one reaction to find the rate of another reaction was reinforced a clock reaction. This was possible using starch as the indicator for the presence of iodine ions. The thiosulphate ions would consume the iodide ions, leaving the solution colourless. As soon as the thiosulphate ions are all used up, the solution will have free iodine molecules, forming an iodine-starch complex thus yielding the violet colour in solution. Conclusion Ultimately, the experiment was successful in calculating the rate law for the iodide-persulphate reaction. The experimenters observed the effect of concentration reaction rates such that as the 10
11 concentration of a reactant increases, the rate of reaction increases, and as the concentration of a reactant decreases, the rate of reaction decreases. The experiment helped carry out the different runs of the iodidepersulphate reaction using different concentrations of each ion. The reaction was timed when moles of thiosulphate was used up, and this was possible in using a clocking technique. ogarithmic graphs were plotted to calculate the orders of the reaction with respect to each reactant specie. The rate law was then determined to be: Rate = [I - ][S 2 O 8 ]. If this experiment was redone, to calculate a more accurate and precise rate constant value, each run should be tested for multiple times so that an average t value could be calculated. This would yield a more accurate rate constant because then the experimenters would have an average reaction time to work with, thus taking the value that lies in the middle of the dataset. With only one reaction time value, it is hard to tell if the information agree with each other or are of expected values. One type of random error that could have affected the data is a varying temperature change throughout the period of the lab. If the temperature was not constant all through the lab, the data would have been skewed depending on whether the temperature was decreasing or increasing. Another error could have arose from the fact that the persulphate ions have a small tendency to react with the thiosulphate ions, thus providing an incorrect reaction rate and rate constant. The iodide ion could have reacted with the iodine molecule to produce a triiodide ion, which could have reacted with the persulphate ion. This is also another possibility from which discrepancies could have arisen. References Gillenwater, J. Y. (2002). Adult and Pediatric Urology. Philadelphia: ippincott Williams & Wilkins. evine, I. N. (2002). Physical Chemistry, 5th Ed. New York: McGraw Hill. Moya, M.., Izquierdo, C., & Casado, J. (1991). Microemulsions as a medium in chemical kinetics; the persulphate-iodide reaction. The Journal of Physical Chemistry, The Rate of an Iodine Clock Reaction. (n.d.). Retrieved March 8, 2013, from comcast: 11
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 informationCHEM 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 informationCHEM 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#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 informationExperiment 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 informationExperiment 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 informationDetermining 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 informationChemical Kinetics Ziyue Zhu 2015/2/4
Chemical Kinetics Ziyue Zhu 2015/2/4 Introduction: The purpose of this experiment was to measure the effects of changes in the concentrations of reactants and temperature on the rate of a reaction. The
More informationDetermination 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 informationEXPERIMENT 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 informationRate 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 informationRate 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 informationEXPERIMENT 3 THE IODINE CLOCK
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
More informationKinetics 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 informationA 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 informationKinetics 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 informationIODINE 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 informationKinetics; 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 informationExperiment #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 informationCHM112 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 informationCHM112 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 informationExamining 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 informationExperiment 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 informationChemistry 40S Chemical Kinetics (This unit has been adapted from
Chemistry 40S Chemical Kinetics (This unit has been adapted from https://bblearn.merlin.mb.ca) Name: 1 2 Lesson 1: Introduction to Kinetics Goals: Identify variables used to monitor reaction rate. Formulate
More informationTHE 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 informationExperimental 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 informationPRACTICAL 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 informationClocking the Effect of Molarity on Speed of Reaction. reaction. While most people do assume that the temperature of the solution is often the most
Ding 1 Chunyang Ding Mr. Rierson AP/IB Chemistry SL 28 January 2013 Clocking the Effect of Molarity on Speed of Reaction In basic levels of chemistry, most of the experimenter s attention is on the reaction
More informationU N I T T E S T P R A C T I C E
South Pasadena AP Chemistry Name 2 Chemical Kinetics Period Date U N I T T E S T P R A C T I C E Part 1 Multiple Choice You should allocate 30 minutes to finish this portion of the test. No calculator
More information15. 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 informationU N I T T E S T P R A C T I C E
South Pasadena AP Chemistry Name 3 Chemical Equilibrium Period Date U N I T T E S T P R A C T I C E Part 1 Multiple Choice You should allocate 30 minutes to finish this portion of the test. No calculator
More informationChemistry 141 Laboratory Lab Lecture Notes for Kinetics Lab Dr Abrash
Q: What is Kinetics? Chemistr 141 Laborator Lab Lecture Notes for Kinetics Lab Dr Abrash Kinetics is the stud of rates of reaction, i.e., the stud of the factors that control how quickl a reaction occurs.
More informationLecture (8) Effect of Changing Conditions on the Rate Constant
Lecture (8) Effect of Changing Conditions on the Rate Constant The relationship between the rate of a chemical reaction and the concentration of the reactants is shown by the rate equation of the reaction.
More informationKinetics Practice Test 2017 Name: date: 1. Use the data provided the answer the question.
Kinetics Practice Test 2017 Name: date: 1. Use the data provided the answer the question. The data above was obtained for a reaction in which X + Y Z. Which of the following is the rate law for the reaction?
More informationCHEMISTRY 225 SEMESTER REACTION KINETICS
CHEMISTRY 225 SEMESTER 01-2007 REACTION KINETICS 1) Dinitrogen pentoxide (N 2 O 5 ) decomposes slowly when in solution in tetrachloromethane to form nitrogen dioxide and oxygen. The reaction may be represented
More informationName AP CHEM / / Chapter 12 Outline Chemical Kinetics
Name AP CHEM / / Chapter 12 Outline Chemical Kinetics The area of chemistry that deals with the rate at which reactions occur is called chemical kinetics. One of the goals of chemical kinetics is to understand
More informationKinetics and Mechanisms of the Iodine Clock. Reaction
0 Kinetics and Mechanisms of the Iodine Clock Reaction Chikarmane and Jonathan White Department of Chemistry University of Oregon Eugene, OR 97403 May 18, 2014 Abstract: The mechanism by which the iodide/peroxide
More informationWhat Is the Rate Law for the Reaction Between Hydrochloric Acid and Sodium Thiosulfate?
What Is the Rate Law for the Reaction Between Hydrochloric Acid and Sodium Thiosulfate? Introduction The collision theory of reactions suggests that the rate of a reaction depends on three important factors.
More informationUNIT 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 informationChapter 14 Chemical Kinetics
Chapter 14 Chemical Kinetics Factors that Affect Reaction rates Reaction Rates Concentration and Rate The Change of Concentration with Time Temperature and Rate Reactions Mechanisms Catalysis Chemical
More informationProperties of Solutions and Kinetics. Unit 8 Chapters 4.5, 13 and 14
Properties of Solutions and Kinetics Unit 8 Chapters 4.5, 13 and 14 Unit 8.1: Solutions Chapters 4.5, 13.1-13.4 Classification of Matter Solutions are homogeneous mixtures Solute A solute is the dissolved
More informationCHEMISTRY - CLUTCH CH.13 - CHEMICAL KINETICS.
!! www.clutchprep.com CONCEPT: RATES OF CHEMICAL REACTIONS is the study of reaction rates, and tells us the change in concentrations of reactants or products over a period of time. Although a chemical
More informationCHEM N-4 November 2014
CHEM1002 2014-N-4 November 2014 The reaction order for a chemical reaction is given by the sum of the powers in the rate law. Why is the reaction order usually given by a small positive integer, i.e. 2
More informationKINETICS 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 informationEXPERIMENT 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 informationU N I T T E S T P R A C T I C E
South Pasadena AP Chemistry Name 3 Chemical Equilibrium Period Date U N I T T E S T P R A C T I C E Part 1 Multiple Choice You should allocate 30 minutes to finish this portion of the test. No calculator
More information21-Jan-2018 Chemsheets A Page 1
www.chemsheets.co.uk 21-Jan-2018 Chemsheets A2 1001 Page 1 SECTION 1 Recap of AS Kinetics What is reaction rate? The rate of a chemical reaction is a measure of how fast a reaction takes place. It is defined
More informationName. Chem 116 Sample Examination #2
page 1 of 8 Name Last 5 digits of Student Number: XXX X Chem 116 Sample Examination #2 This exam consists of eight (8) pages, including this cover page. Be sure your copy is complete before beginning your
More informationA 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 informationSolubility Product Constant (K sp ) and the Common-Ion Effect for Calcium Iodate, a Salt of Limited Solubility
Solubility Product Constant (K sp ) and the Common-Ion Effect for Calcium Iodate, a Salt of Limited Solubility Purpose Determine the solubility product constant (K sp ) for a sparingly soluble salt. Study
More informationThe 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 informationPURPOSE: 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 informationChapter 4. Chemical Quantities and Aqueous Reactions
Lecture Presentation Chapter 4 Chemical Quantities and Aqueous Reactions Reaction Stoichiometry: How Much Carbon Dioxide? The balanced chemical equations for fossilfuel combustion reactions provide the
More informationCHEMpossible. Final Exam Review
CHEMpossible Final Exam Review 1. Given the following pair of reactions and their equilibrium constants: 2NO 2 (g) 2NO (g) + O 2 (g) K c = 15.5 2NO (g) + Cl 2 (g) 2 NOCl (g) K c = 3.20 10-3 Calculate a
More informationIB 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 informationKinetics CHAPTER IN THIS CHAPTER
CHAPTER 14 Kinetics IN THIS CHAPTER Summary: Thermodynamics often can be used to predict whether a reaction will occur spontaneously, but it gives very little information about the speed at which a reaction
More informationIodine 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 informationChapter: Chemical Kinetics
Chapter: Chemical Kinetics Rate of Chemical Reaction Question 1 Nitrogen pentaoxide decomposes according to equation: This first order reaction was allowed to proceed at 40 o C and the data below were
More informationExperiment [RCH 2 Cl] [OH ] Initial rate/mol dm 3 s
1. The kinetics of the hydrolysis of the halogenoalkane RCH 2 Cl with aqueous sodium hydroxide (where R is an alkyl group) was studied at 50 ºC. The following results were obtained: Experiment [RCH 2 Cl]
More information(b) Increase in pressure. (1)
1 This question is about the equilibrium reaction between hydrogen and carbon dioxide. H 2 (g) + O 2 (g) H 2 O(g) + O(g) H = +40 kj mol 1 What effect would the following changes have on the rate of reaction
More informationThe rate equation relates mathematically the rate of reaction to the concentration of the reactants.
1.9 Rate Equations Rate Equations The rate equation relates mathematically the rate of reaction to the concentration of the reactants. For the following reaction, aa + bb products, the generalised rate
More informationChemistry 12 August 2003 Provincial Examination
Chemistry 1 August 003 Provincial Examination ANSWER KEY / SCORING GUIDE CURRICULUM: Organizers 1. Reaction Kinetics. Dynamic Equilibrium 3. Solubility Equilibria 4. Acids, Bases, and Salts 5. Oxidation
More informationACTIVATION 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 informationEXPERIMENT - 2 DETERMINE THE PRODUCT OF A REDOX REACTION REACTION OF BROMATE AND HYDROXYLAMMONIUM IONS CHM110H5F
EXPERIMENT - 2 DETERMINE THE PRODUCT OF A REDOX REACTION REACTION OF BROMATE AND HYDROXYLAMMONIUM IONS CHM110H5F EXPERIMENT PERFORMED ON: 03 OCTOBER, 2012 REPORT SUBMITTED ON: 10 OCTOBER, 2012 SUBMITTED
More informationOH (ammonium hydroxide) are in 3.47 moles of NH 4. OH? 1 grams. 2 Na(s) + Cl 2. (g) 2 NaCl(s) (32.00 g/mol) according to the reaction C 3
Question #: 1 Posting ID: 423347 Course: CHE 105 2015 SU Instructor: Sarah Edwards How many grams of NH 4 OH (ammonium hydroxide) are in 3.47 moles of NH 4 OH? 1 grams Question #: 2 When 2.61 grams of
More informationTHE COLLEGE OF THE BAHAMAS
TE CLLEGE F TE BAAMAS MIDSEMESTER EXAMINATIN SEMESTER 01-010 FACULTY F PURE AND APPLIED SCIENCES SCL F CEMISTRY, ENVIRNMENTAL & LIFE SCIENCES X NASSAU FREEPRT EXUMA ELEUTERA DATE F EXAMINATIN: Monday 1
More informationEXPERIMENT 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 informationEXPERIMENT 22 SOLUBILITY OF A SLIGHTLY SOLUBLE ELECTROLYTE
EXPERIMENT 22 SOLUBILITY OF A SLIGHTLY SOLUBLE ELECTROLYTE INTRODUCTION Electrolytes are compounds that are present in solution as ions. They are more likely to be soluble in water than in most other liquids
More informationTHE 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[Ca 2+ ] = s (3) [IO - 3 ] = 2s (4)
E10 Chemical Equilibria: K sp of Calcium Iodate Objective! Understand the relation between the molar solubility and the solubility product constant of a sparingly soluble salt.! Measure the molar solubility
More informationb. Free energy changes provide a good indication of which reactions are favorable and fast, as well as those that are unfavorable and slow.
Chem 130 Name Exam 3, Ch 7, 19, 14 November 9, 2018 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with the correct
More informationAP CHEMISTRY CHAPTER 12 KINETICS
AP CHEMISTRY CHAPTER 12 KINETICS Thermodynamics tells us if a reaction can occur. Kinetics tells us how quickly the reaction occurs. Some reactions that are thermodynamically feasible are kinetically so
More informationALE 1. Chemical Kinetics: Rates of Chemical Reactions
Name Chem 163 Section: Team Number: ALE 1. Chemical Kinetics: Rates of Chemical Reactions (Reference: Sections 16.1 16.2 + parts of 16.5 16.6 Silberberg 5 th edition) How do the surface area, concentration
More informationThe solvent is the dissolving agent -- i.e., the most abundant component of the solution
SOLUTIONS Definitions A solution is a system in which one or more substances are homogeneously mixed or dissolved in another substance homogeneous mixture -- uniform appearance -- similar properties throughout
More informationL = 6.02 x mol Determine the number of particles and the amount of substance (in moles)
1.1 The Mole 1.1.1 - Apply the mole concept to substances A mole is the name given to a certain quantity. It represents 6.02 x 10 23 particles. This number is also known as Avogadro's constant, symbolised
More informationMole: base unit for an amount of substance A mole contains Avogadro s number (N A ) of particles (atoms, molecules, ions, formula units )
Mole: base unit for an amount of substance A mole contains Avogadro s number (N A ) of particles (atoms, molecules, ions, formula units ) N A 6.0 10 mol -1 1 mol substance contains N A Molar mass (g/mol)
More informationStudent Number Initials N. G Z. Mc Z. Mo T. N H. R M. S M. T.
Student Number Section 003 Initials 5037785 N. G. 50417065 Z. Mc. 50419357 Z. Mo. 50418455 T. N. 50184967 H. R. 503899 M. S. 5038787 M. T. Find Jan or Sandy asap in the Chem. labs Section 006 Student Number
More informationKinetics 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 informationA 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 informationAP Chem Chapter 14 Study Questions
Class: Date: AP Chem Chapter 14 Study Questions 1. A burning splint will burn more vigorously in pure oxygen than in air because a. oxygen is a reactant in combustion and concentration of oxygen is higher
More informationKinetics of Crystal Violet Fading AP Chemistry Big Idea 4, Investigation 11 An Advanced Inquiry Lab (adapted by Flinn Scientific, Inc.
Introduction Kinetics of Crystal Violet Fading AP Chemistry Big Idea 4, Investigation 11 An Advanced Inquiry Lab (adapted by Flinn Scientific, Inc.) Crystal violet is a common, beautiful purple dye. In
More informationConcentration 0. 5 M solutions 1. 0 M solutions. Rates Fast Slow. Which factor would account for the faster reaction rate in Experiment 1?
72. Consider the following experimental results: Experiment 1 Experiment 2 2+ - - 4 2 2 4 aq Reactants Fe ( aq) + MnO4 ( aq) MnO ( aq) + H C O ( ) Temperature 20 C 40 C Concentration 0. 5 M solutions 1.
More informationNCEA COLLATED QUESTIONS ON RATES OF REACTION
NCEA COLLATED QUESTIONS ON RATES OF REACTION Previously part of expired AS 90301, now part of 91166, Demonstrate understanding of chemical reactivity 2012 (91166 exam) When dilute hydrochloric acid, HCl(aq),
More informationWe can csalculate the MASS FRACTION of each component, then multiply the mass fraction by 56 g (the sample's actual mass) to get the mass of each
87 We can csalculate the MASS FRACTION of each component, then multiply the mass fraction by 56 g (the sample's actual mass) to get the mass of each component. 88 Commercial sulfuric acid (98% by mass)
More informationHow 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 informationEquilibrium. What is equilibrium? Hebden Unit 2 (page 37 69) Dynamic Equilibrium
Equilibrium What is equilibrium? Hebden Unit (page 37 69) Dynamic Equilibrium Hebden Unit (page 37 69) Experiments show that most reactions, when carried out in a closed system, do NOT undergo complete
More informationKinetics 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 informationChapter 4 Reactions in Aqueous Solution
Chapter 4 Reactions in Aqueous Solution Homework Chapter 4 11, 15, 21, 23, 27, 29, 35, 41, 45, 47, 51, 55, 57, 61, 63, 73, 75, 81, 85 1 2 Chapter Objectives Solution To understand the nature of ionic substances
More informationPartner: 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 informationCHEMICAL KINETICS. Collision theory and concepts, activation energy and its importance VERY SHORT ANSWER QUESTIONS
Topic-3 CHEMICAL KINETICS Collision theory and concepts, activation energy and its importance 1. What is law of mass action? VERY SHORT ANSWER QUESTIONS This law relates rate of reaction with active mass
More informationPhysicsAndMathsTutor.com. Advanced Subsidiary Unit 3: Chemistry Laboratory Skills I
Write your name here Surname Other names Pearson Edexcel International Advanced Level Centre Number Chemistry Advanced Subsidiary Unit 3: Chemistry Laboratory Skills I Candidate Number Monday 7 November
More informationReaction Kinetics. Reaction kinetics is the study of the rates of reactions and the factors which affect the rates. Hebden Unit 1 (page 1 34)
Hebden Unit 1 (page 1 34) Reaction kinetics is the study of the rates of reactions and the factors which affect the rates. 2 1 What are kinetic studies good for? 3 How to speed up: 1. Paint drying 2. Setting
More informationSchools Analyst Competition
Royal Society of Chemistry Analytical Division North West Region Schools Analyst Competition 19 th April 2005 Experimental Handbook Adran Cemeg - Department of Chemistry Prifysgol Cymru - University of
More informationKinetics of Crystal Violet Fading AP* Chemistry Big Idea 4, Investigation 11 An Advanced Inquiry Lab
Introduction Kinetics of Crystal Violet Fading AP* Chemistry Big Idea 4, Investigation 11 An Advanced Inquiry Lab Catalog o. AP7644S Publication o. 7644S Crystal violet is a common, beautiful purple dye.
More informationChem 401 Unit 1 Exam: Thermodynamics & Kinetics (Nuss: Spr 2018)
Date: Exam # Chem 401 Unit 1 Exam: Thermodynamics & Kinetics (Nuss: Spr 2018) Multiple Choice Identify the choice that best completes the statement or answers the question. (3 pts each) 1. Which of the
More informationWhen a solution of thiosulfate is acidified, the following reaction takes place: S2O3 2 - (aq) + 2H + (aq) H2O + SO2 (g) + S (s) (1)
EXPERIMENT 1 The Kinetics of a Thiosulfate Solution INTRODUCTION: Various approaches are used to study the kinetics of reactions. A usual procedure is to monitor some property, such as intensity of color
More informationThe Mole. Relative Atomic Mass Ar
STOICHIOMETRY The Mole Relative Atomic Mass Ar Relative Molecular Mass Mr Defined as mass of one atom of the element when compared with 1/12 of an atom of carbon-12 Some Ar values are not whole numbers
More informationChemistry 12 April 2003 Provincial Examination
Chemistry 12 April 2003 Provincial Examination ANSWER KEY / SCORING GUIDE CURRICULUM: Organizers 1. Reaction Kinetics 2. Dynamic Equilibrium 3. Solubility Equilibria 4. Acids, Bases, and Salts 5. Oxidation
More informationChem 130 Name Exam 2 October 11, Points Part I: Complete all of problems 1-9
Chem 130 Name Exam October 11, 017 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with the correct units and significant
More informationFactors That Affect Rates. Factors That Affect Rates. Factors That Affect Rates. Factors That Affect Rates
KINETICS Kinetics Study of the speed or rate of a reaction under various conditions Thermodynamically favorable reactions DO NOT mean fast reactions Some reactions take fraction of a second (explosion)
More information