Kinetics: The Iodination of Propanone

Kinetics The Iodination of acetoneMary AdesinaThis individual investigation pull up stakes be exploring kinetics through experimentation the receptionThis contradiction is described as autocatalytic as it is produces the very species that increases the direct of reaction (hydrogen ions7).BackgroundReactants atomic number 53 is chemical that takes place in the reaction. Iodine is a halogen (group 7 on the periodic table) with a simple moleeecular covalent structure. Halogens are often diatomic as they nominate seven electrons on their outermost shell (a full shell world eight) so to share electrons would allow them to be stable. Halogens are very electronegative elements meat they are very possible to attract a bonding pair of electrons. As one if the less reactive halogens Iodine is a grey solid in standard conditions, this is repayable to it being a bigger so the outer electrons are further from the nucleus and thus harder for the attraction of an electron to form and Halide ion12.The other halogens consist of Fluorine, Chlorine, atomic number 35 and Astatine.Fluorines material state is a pale yellow gas as it is the most reactive halogen. However it may not react with propanone in the same way as ace as it does be lay down as a very good nucleophile. This is due to fluorine being less ready to share electrons with the electrophilic carbon in propanone.Chlorines physical state is a green gas and arouse be make into a virtually colourless solution but in this particular reaction will produce Chloroacetone ( utilize as tear gas in the war) 10. This would throw up everyone is the laboratory at risk as tear gas can cause tearing, coughing and sneezing but inflaming mucous membranes in the eyes, perfume and mouth. ever-changing the type of ketone in the reaction to butanone will prevent this haloketone from being produced, however the new ketone has a different chain length and and and so there is a need to attempt if there is a significant deviance between the rates of the reaction the iodination of propanone and the iodination of butanone.Bromines physical state is a red-brown liquid and is yellow/orange in solution that reacts with propanone in a way that is analogous to single4. This halogen is to a greater extent than reactive than iodine as thus should result in a faster reaction rate12.Astatine cannot be used in this reaction as it is further in any case unreactive as well as radioactive.Propanone (also know as acetone) is the most simple of ketones consisting of three carbons. Ketones are formed by refluxing secondary alcohols with acidified cat valium Dichromate Figure 4.ProductsIodopropane is produced in the reactionSpectator IonsTheoryIn order for a reaction to take place particles need to collide, as occurs goose egg is shifted between them changing the amount of energy they have this is known as Collision Theory13. The distribution of this energy is displayed in a Maxwell-Boltzmann frizzle Figure 2 . The factors that have positive correlation with the rate constant3 and therefore effect the rate of a reaction do so because they affect the number of collisions (concentration) or the energy that for each one particle possesses (temperature) because this effects the number of particles that possess the activating energy (the minimum energy required for the reaction to take place)13. Catalysts also affect the rate of reaction by providing an alternative route for the reaction to occur this route has a lower activation energy than the original reaction Figure 2 meaning more particles have enough energy to react thus increasing the reaction rate.If a reaction has a great activation energy, the increase in temperature will have a large effect on the rate of reaction whereas if this activation energy was smaller, the change in temperature will be far less significant. This suggests that there is a relationship between reaction rate, temperature and activation energy. Due to this rel ationship the Arrhenius equation, utilise the temperature dependence of the rate constant 13(k Figure 1), is apply to calculate activation energy of reaction via deriving a form of that fits y=mx+c (taking the natural logarithm).Rate of reaction is defined as the speed at which reactants are formed into products or change in concentration over time taking into consideration the factors that affect it such as surface area, temperature and concentration13. There are many ways of metre the concentration during a reaction but some are more efficient depending on the property that changes during the reaction. For example, the original reaction being investigated, the iodination of propanone, has an obvious colour change so a technique that detects absorbance (Colorimetry) would be a more efficient than measuring loss of mass when there is no gas released3.With many techniques there arises the need to convert a particular property to concentration, in order to do so a calibration curve is needed. This curve is created by selecting known concentrations and measuring the level or amount of the property associated with the reaction and then gulp a property-concentration curve Figure x. Although it may be referred to as a curve more often than not it turns out to be rather elongate as the concentrations used are rather low as the reactions would occur far too quickly if they were any higher, also high concentrations tend to have a higher hazard.It is only through practical experiments that a rate equation giving the order of reactants can be written5.0 order Changing the concentration of this species has no effect on the rate of reaction.1st order The rate of reaction is directly proportional to the rate of reaction.2nd order As the concentration doubles the rate of reaction quadruples (exponential relationship).The overall order of a reaction is calculated by adding the orders of each species Figure 1.The order of a reaction with respect to A shows the number of m olecules of A which are involved in the rate find step. As a result of this a mechanism can be suggested if the rate equation is known as if the reactant is not in the rate equation it cannot feature in the rate ascertain step. The rate determining step is the slowest step in the reaction and thus it is responsible for the rate of the overall reaction. This step can be first or utmost (Bottleneck effect) and it would make no difference on the overall reaction rate. aspirationsExplore the effects of different accelerators on the rate of the reaction and thus the activation energy. by and by finding the rate equation for the original equation, the same experiment will be carried out with catalysts sulphuric, nitric and hydrochloric acid then with no catalyst (see reactions below). The activation energy can then be calculated via finding the different rates of reaction and thus the different values of the rate constant. This is all anticipate the spectator ions have no effect on t he reaction.Explore the effects of changing the type of halogen on the rate of the reaction.The chosen halogens are Bromine and Chlorine. The pursuance are the reactions that are going to take place as a result (respectively).Use rate equation to propose a rate determining step and explore a suggested mechanism.If time permits exploring a suggested mechanism may consist of testing the presence of a product of one of the steps in the mechanism.TechniquesColorimetryThis technique will be used to calculate the order of the reaction between iodine and propanone.This technique will also be used to measure the rates of the reactions betweenIodine and propanoneIodine and butanoneBromine and propanoneHypothesis Although the ketones propanone and butanone have different formulas, the difference between the rates of reactions will be negligible and therefore the results for the reaction between chlorine with butanone and chlorine with propanone are more or less similar.Equipment ListChemical List9 Boiling Tubes10ml PipetteSpark Data loggerPipette FillerColorimeter20ml of 0.02 mol dm-3 Iodine10ml of 0.02 mol dm-3 Bromine20ml of 0.02 mol dm-3 Propanone10ml of 0.02 mol dm-3 Butanone30ml 0.02 mol dm-3 HCLDistilled waterCalibration CurveSet up the colorimeter according to the instructions. station a cuvette full of distilled water inside the colorimeter and press the zero the button. take away a suitable filter (gives your greatest concentration an absorption of most to one). propose up 0.04, 0.016, 0.004, 0.0016, 0.0004, and 0.00016 mol dm-3 of iodine solution in test provides by adding distilled water.Label each test tube.Place 6 ml 0.04 mol dm-3 of iodine solution in a cuvette and record the absorbanceDo the same for each of the other concentrations.Draw a calibration curve by placing known concentrations of iodine solution in the colorimeter and transcription the absorption.Only repeat the concentrations that dont seem to fit in the curve.Method To achieve Aim 1Attach data logger to collect data automatically.Place a cuvette full of distilled water inside the colorimeter and press the zero the button.Select a suitable filter (gives your greatest concentration an absorption of close to one). motley sample A, sample B and 2 ml of 0.02 mol dm-3 HCL in a cuvette (add sample A last). this instant place cuvette inside the colorimeter and start recording absorbance at time intervals of 30 seconds for 6 minutes victimization the data logger. borrow Steps 2 to 5 two more times and calculate an average.Use calibration curve to convert absorbance to concentration then excerpt a concentration-time graph.Sample ASample B prove 12ml of 0.02 mol dm-3 Iodine2ml of 0.02 mol dm-3 PropanoneExperiment 22ml of 0.02 mol dm-3 Iodine2ml of 0.02 mol dm-3 ButanoneExperiment 32ml of 0.02 mol dm-3 Bromine2ml of 0.02 mol dm-3 PropanoneMethod To achieve Aim 3 (Determine a rate equation)Attach data logger to collect data automatically.Place a cuvette full of distilled water inside the colorimeter and press the zero the button.Select a suitable filter (gives your greatest concentration an absorption of close to one).Add sample A, sample B and sample C in a cuvette.Immediately after adding Xml of 0.02 mol dm-3 Iodine sol, place the cuvette inside the colorimeter.Start recording absorbance at time intervals of 30 seconds for 6 minutes using the data logger.Repeat Steps 2 to 6 two more times and calculate an average.Sample ASample BSample CXExperiment 10.9ml of 0.02 mol dm-3 Propanone0.9ml of 0.02 mol dm-3 HCL3.3ml distilled water0.9Experiment 21.8ml of 0.02 mol dm-3 Propanone0.9ml of 0.02 mol dm-3 HCL2.4ml distilled water0.9Experiment 30.9ml of 0.02 mol dm-3 Propanone1.8ml of 0.02 mol dm-3 HCL2.4ml distilled water0.9Experiment 40.9ml of 0.02 mol dm-3 Propanone0.9ml of 0.02 mol dm-3 HCL2.4ml distilled water1.8Use calibration curve to convert absorbance to concentration then draw a concentration-time graph.Conductivity Meter11This technique will be used to measure and compare the reaction rates of the iodination of propanone with a different catalysts.Hypothesis The catalyst with the most hydrogen ions available will have the fastest reaction of rate and thus the lowest activation energy. This is assuming the spectator ions have no effect on the conductivity meter.Equipment ListChemical List100ml BeakerConductivity Meter10ml PipettePipette filler2 Water bathsKettle/ bunsen BurnerTest tubes220cm3 of 0.02 mol dm-3 Propanone120cm3 of 0.02 mol dm-3 HCL60cm3 of 0.02 mol dm-3 H2SO4220cm3 of 0.02 mol dm-3 HNO3220cm3 of 1 mol dm-3 IodineDistilled waterMethod To achieve Aim 3 (Effect of catalysts on activation energy) annoy two water baths (one large one small) at X degrees Celsius using a kettle and tap water.Label 2 test tubes A and B then fill with 9ml of 0.02 mol dm-3 Propanone and 9ml of 0.02 mol dm-3 Iodine respectively.XExperiment 110Experiment 220Experiment 330Experiment 440Experiment 550Experiment 660Label 3 more test tubes X,Y and Z then fill with 3ml of 0.02 mol dm-3 H2SO4 , 3ml of 0.02 mol dm-3 HCL and 3ml of 0.02 mol dm-3 HNO3 respectively.Place all of the test tubes in the small water bath for 2 minutes.Place a beaker in the large water bath.Pour 3 ml from test tubes A and X into the beaker.Place conductivity probe in the beaker and adjust settings to consider the temperature of the water bath.Add 3ml from test tube B into the beaker.Start conductivity probe and record the conductivity every 30 seconds for 6 minutes.Repeat steps 6 to 9 but using the table of contents of test tube Y.Repeat steps 6 to 9 but using the contents of test tube Z.Repeat steps 1 to 11 two more times and calculate an average.Titration9, 12 14This technique will be used to measure the decrease in concentration of chlorine water throughout the reaction between chlorine solution and butanone in order to find the initial rate of reaction. As chlorine solution is virtually colourless it would be more effective to conduct an analysis that doesnt rely on a colour change.A Redox titration will be used to measure the decrease in iodine concentration to pick up that the technique used to collect data doesnt have a significant effect on the results. sodium enthalpy Carbonate will be used to decimate the reaction as it removes the hydrogen ions from the reaction.Silver nitrate TitrationThe chloride ions produced by the reaction will react with the silver nitrate to form a white precipitate (silver chloride).The end-point of the titration is a red precipitate caused by silver chloride reacting with the Sodium Chromate to form Silver Chromate(VI).Redox TitrationThe iodide ions produced by the reaction will oxidate the Sodium Thiosulphate, so the thiosulphate ions become tetrathionate ions in a redox reaction.The solution will gradually start to go from brown to almost pale yellow. When this happens the starch indicator is added and reacts with triiodide forming a very dark blue-black complex. The end point is when this so lution becomes colourless because it means that there is no perennial any iodine left.Hypothesis As Chlorine is more reactive than Iodine, the rate of the reaction should be faster. This is assuming that the technique has no significant effect on the results gained in this experiment.Equipment ListChemical ListDistilled Water2 Conical FlasksTest tubesA White TileStopwatchBeakerWhite paper50 ml of 1 mol dm-3 Sodium Hydrogen CarbonateSodium Chromate50 ml Silver process100ml of 0.02 mol dm-3 ChlorineButanoneCalibration Curve for ChlorineSet up apparatus as seen in picture above.Mark white sheet of paper with a large black cross.Make up 10ml of 0.04, 0.016, 0.004, 0.0016, 0.0004, and 0.00016 mol dm-3 Chlorine solution in test tubes by adding distilled water.Label each test tube.For each test tube Pour the contents of the test tube into a conical flask along with 1g Sodium Chromate dissolved in 20 ml distilled water.Place conical flask on white sheet under burette.Fill a burette with a recorded amount of 0.1 mol dm-3 Silver Nitrate solution.Add drops of Silver Nitrate solution into the solution, swirling after every few drops, there will be a white precipitate formed.Add more drops until the cross is no lasting visible due to a brick red precipitate forming.Record the new amount of Silver Nitrate in the burette.Repeat steps 3 to 10 two more times and calculate an average titre (difference of 0.1).Method To achieve Aim 1 (Reaction rate of Chlorine and Butanone)XExperiment 11Experiment 21.5Experiment 32Experiment 42.5Experiment 53Experiment 63.5Experiment 74Set up apparatus as seen in picture above.Mark white sheet of paper with a large black cross.Mix 3ml of 0.02 mol dm-3 Butanone, 3ml of 0.02 mol dm-3 HCL and 3ml of 0.02 mol dm-3 Chlorine in a conical flask.After X minutes add 3ml of 1 mol dm-3 Sodium Hydrogen Carbonate to quench the reaction.Add 1g Sodium Chromate dissolved in 20 ml distilled water to the conical flask.Place conical flask on a white sheet under burette.Fill a burette with a recorded amount of 0.1 mol dm-3 Silver Nitrate solution.Add drops of Silver Nitrate solution into the solution, swirling after every few drops, there will be a white precipitate formed.Add more drops until the cross is no longer visible due to a brick red precipitate forming.Repeat steps 3 to 9 two more times and calculate an average titre (difference of 0.1).Use calibration curve to obtain a concentration-time graph.Calibration Curve for IodineSet up apparatus as seen in picture above.Make up 10 ml of 0.04, 0.016, 0.004, 0.0016, 0.0004, and 0.00016 mol dm-3 iodine solution in test tubes by adding distilled water.Label each test tube.For each test tube Pour the contents of the test tube into a conical flask.Add 3ml of Starch indicator to the conical flask.Fill a burette with Sodium Thiosulphate, recording the amount.Add drops of Sodium Thiosulphate into the solution, swirling after every few drops until there is a permanent colour change from a Black-B lue to colourless.Record the new amount of Sodium Thiosulphate in the pipette.Repeat steps 1 to 7 two more times and calculate an average titre (difference of 0.1).Method To achieve Aim 1 (Reaction rate of Iodine and Propanone)Set up apparatus as seen in picture above.Mix 3ml of 0.02 mol dm-3 Propanone, 3ml of 0.02 mol dm-3 HCL and 3ml of 0.02 mol dm-3 Iodine in a conical flask.XExperiment 11Experiment 21.5Experiment 32Experiment 42.5Experiment 53Experiment 63.5Experiment 74After X minutes add 3ml of 1 mol dm-3 Sodium Hydrogen Carbonate to quench the reaction.Add 3ml of Starch Indicator to the solution.Fill a burette with Sodium Thiosulphate, recording the amount.Add drops of Sodium Thiosulphate into the solution, swirling after every few drops until there is a permanent colour change from Blue-Black to colourless.Record the new amount of Sodium Thiosulphate in the pipette.Repeat steps 1 to 7 two more times and calculate an average titre (difference of 0.1).Use calibration curve to obtain a concentration-time graph. encounter AssessmentChemical/ProcedureHazardRiskAction if OccurredPrecautionsRisk Likelihood (out of 10)ColorimetryTitration(Precipitation)Use of a Conductivity MeterPropanoneButanoneIodineChlorineBromineHydrochloric Acid sulfuric AcidNitric AcidSodium Hydrogen CarbonateIodopropanoneChlorobutanoneBromopropanoneIodine/Bromide/Chloride ionsSodium NitrateSodium ChromateStarch IndicatorSodium Thiosulphate1 Page