Iodine Clock Reaction Essay Sample
1. Investigate the consequence of temperature on the rate of reaction.
For this purpose 3 sets of consequences will be obtained by clocking how long it takes for the coloring material alteration to happen in different temperatures determined by the usage of an electric H2O bath. With these consequences. the consequence of temperature on the rate of reaction will be investigated.
2. Determine the activation heat content with and without the accelerator ammonium molybdate ( VI ) and with different protic acids and utilize this to compare the effectivity.
To happen out which accelerator is most effectual. this purpose will be carried out as an I clock reaction. The end of this purpose is to happen out what accelerator is best to do this reaction occur at the fastest rate.
3. Determine the effects of the presence of ethyl alcohol on the rate equation.
It is known that ethanol effects H peroxide and therefore it has an consequence on the rate equation. This purpose will happen out the consequence of ethyl alcohol by transporting out the I clock reaction with and without ethanol nowadays and the consequences will be compared to pull a decision.
4. Investigate the order of reaction with regard to hydrogen peroxide. iodide and acid.
The end of this purpose is to happen out what order of reaction each chemical produced by doing a graph for each of the reactants and analyzing the line of best tantrum.
5. Investigate the rate equation. rate changeless and possible mechanism for this reaction.
Investigating the possible mechanism will picture why the reaction occurs as it does. This purpose is theory based and it will inform as to how the chemicals react and how this forms the merchandises. By happening the rate equation. the dependance of rate on the concentration can be worked out. The rate invariable will assist to work out the rate equation.
6. Determine how the presence of a accelerator changes the mechanism of the Harcourt-Essen reaction and whether the mechanism is effected by monoprotic. diprotic or tripotic acids.
Catalysts speed up chemical reactions and so this theory based purpose will happen out how this happens and which catalysts is the most efficient at increasing the rate of reaction.
7. To happen out how the concentration of iodide ions and peroxodisulphate ( VI ) ions affects the rate of reaction.
Potassium iodide reacts with H peroxide to organize I. in this purpose the concentration of iodide and peroxodisulphate ions will be measured to see how this effects the rate of reaction.
The equation for this experiment is as follows:
H2O2 ( cubic decimeter ) + 2I- ( cubic decimeter ) + 2H+ ( I2 ( s ) + 2H2O ( cubic decimeter )
2I- ( I2 + 2e-
H202 + 2H+ + 2e- ( 2H2O
In this reaction the iodide ions are oxidised by the H peroxide and turned into I. the H peroxide additions negatrons and is turned into H2O.
The I clock reaction occurs in two parts the first of which is the reactions between I and Na thiosulfate. which produces iodide ions and a tetrathionate anion. The bluish black coloring material of the starch-iodide composite shows up when all of the thiosulphate ions have reacted with the I. The reaction is shown below:
I2 ( s ) + 2S2O32- ( cubic decimeter ) ( 2I- + S4O6 ( cubic decimeter ) –
The iodide ions being responding with the amylum once the thiosulphate ions have been exhausted. this produces the starch-I5- composite that gives the bluish black coloring material that is recorded to give the sum of H peroxide that has reacted and the clip that the reaction took. The equation is shown below:
I2 + amylum ( starch-I5- + I-
The particulars of the reaction between the amylum and I are non wholly known but it is thought that the spirals of amylose are where the I fits. The I transportations charge to the amylum. which combined with the spacing between the energy degrees in the composite that is formed. corresponds to the soaking up spectrum therefore the bluish black coloring material is given off.
The 2nd equation is as follows:
2KMnO4- ( L ) + 5H2O2 ( L ) + 6H+ ( 2KMn2+ ( aq ) + 5O2 ( cubic decimeter ) + 8H2O ( cubic decimeter )
In this equation K permanganate is the reagent as it brings about the coloring material alteration. Potassium permanganate is an inorganic compound which is a salt because it has k+ and MnO4- ions. The oxidising ability of this compound is really strong and it dissolves in H2O to bring forth really dark violet solution. Potassium permanganate was once known as Condy’s crystals because the solution in H2O would vaporize to give prismatic crystals of a purple/black coloring material that glistened.
How the Rate of Reaction Varies:
Harmonizing to the hit theory. every reaction has a minimal energy demand for the molecules to get down responding. Activation energy is the minimal energy required for the reaction to get down. the energy is required to interrupt bonds and organize new 1s so that merchandises can organize. If two molecules collide with energy less than the activation energy so the molecules will non interrupt any bond. which means no new bonds can organize and therefore no reaction has taken topographic point. Temperature affects the activation energy because by heating the reaction. molecules gain kinetic energy therefore take downing the activation energy and hence the reaction can take topographic point faster because the kinetic theory provinces that molecules move faster. Faster traveling molecules are more likely to clash with more energy than the activation energy and hence therefore the reaction takes topographic point faster. Activation energy holds great importance in any reaction and so cognizing the proportions of responding atoms that have adequate energy to reaction is really helpful. All atoms have legion energies that can be shown with gases for which the Maxwell-Boltzmann Distribution shows all the energies of a gas. The Maxwell-Boltzmann Distribution is a graph where the figure of atoms is plotted against energy as shown below:
The figure of molecules is shown by the country under the graph. this graph shows the kinetic energy to ne’er be equal to nothing. As there is no defined maximal value this graph could potentially go on onto eternity and it besides shows that are non many molecules with a high energy.
Increasing the concentration of the reactants can do the reaction occur faster because for a reaction to take topographic point atoms must clash with each other. Increasing the concentration increases the frequence of hits and therefore more successful hits take topographic point and so the overall reaction happens faster. This is because when the concentration additions there are more reactant atoms present to clash. This thought can be displayed with the undermentioned diagram:
In this diagram each atom has an equal opportunity of being hit this means that the opportunities of a ruddy atom clashing with the solid blue atom is 25 % . If another blue atom is added. ( represented by the dotted atom ) . so the concentration has increased and the opportunities of a bluish atom being hit is now 50 % which is a 50 % addition.
The greater the surface country of a reactant. the faster the reaction will take topographic point. This is because a greater surface country means more of the reactant is available to respond in a certain sum of clip for illustration the pulverization signifier of a molecule will respond faster than a solid ball of that molecule because in the pulverization more molecules are available to clash and therefore to respond. Below is a ocular representation of the pulverization illustration:
In the above illustration shows that when the ruddy reactant is a pulverization more atoms are available to respond which means that the reaction happens faster and the rate of reaction additions.
Pressure merely effects reactions with gases. it has no consequence on solids or liquids. When the force per unit area of a reaction is increased the rate of reaction besides increases. Increasing the force per unit area means compacting the gaseous reactant into a smaller volume. this increases the likeliness of hits and as the hit theory provinces ; hits are necessary for a reaction to go on. Pressure uses the same construct as concentration. increases the concentration of a reaction means there are more atoms in a given infinite and increasing the force per unit area means there are more atoms in a smaller sum of infinite. The below equation demonstrates the relationship between force per unit area and the rate of reaction:
pV = nRT
P = force per unit area.
V = volume
n = figure of moles
R = grinder gas invariable
T = Temperature
In this equation RT is a changeless therefore it can be represented by the missive K and the full equation can be rewritten to read:
P = K ( n/v )
( n/v ) is the same as the concentration and so the equation can besides be written as P = kC nevertheless because the concentration is non ever known it is non the best signifier for the equation. This equation shows a proportionality so the concluding equation would be as below:
P ( K ( n/v )
A accelerator speeds up a reaction by supplying an alternate tract that has a lower activation heat content and it remains chemically unchanged at the terminal of the reaction. By supplying a tract that requires a lower activation heat content means that there will be more atoms that have adequate energy to respond and get down interrupting bonds.
The alteration in activation heat content would hold the undermentioned impact on the Maxwell – Boltzmann diagram:
The consequence it would hold on an heat content profile diagram would be as follows:
Catalysts can either adsorb or organize intermediate compounds. Adsorption is normally used auto fumess to do the exhausts safe and make less pollution. This is when molecules attach to a surface utilizing really weak forces such as instantaneous dipole – induced dipole. The bonds between the reactants weaken and interruption and so new bonds are formed between the reactants that form merchandises. The merchandises so spread off from the surface of the accelerator.
Enzymes work by organizing an intermediate that is known as an enzyme-substrate composite. The reactants combine with the accelerator to make an intermediate compound. which is really unstable and reacts about consecutive off. When the intermediate compound reacts it forms the concluding merchandise and the accelerator remains chemically unchanged.
Orders of Chemical reaction:
The rate of reaction is the rate of alteration of a reaction as clip additions which is why rate Torahs are differential equations. Zero order reactions occur seldom. most are either first order or 2nd order. For zero order Torahs the rate is independent of concentration.
The graph below is of a nothing order reaction. In this graph the rate of reaction remains changeless throughout the reaction which means that the gradient is besides changeless which produces the consecutive diagonal line that is seeable. The graph besides shows that the half life decreases as the concentration decreases as there is a smaller each clip.
The zero order graph shows that the rate of reaction is unaffected by the reactant and hence if a reactant is zero order it is non needed in the rate equation as it has no impact on the rate of reaction.
First order graphs show changing rate of reactions throughout the reaction which so means the gradients is besides invariably altering. This produces a curve like the one in the graph below and this graph besides shows that the half-life lessenings as concentration lessenings.
The first order graph shows that the rate of reaction is affected by the reactant and hence first order reactants are included in the rate equation is the reactant has a direct affect on the rate of reaction.
Second order graphs show that the rate of reaction varies throughout the reaction merely like first order graphs nevertheless for 2nd order graphs the invariably altering gradient green goodss and exponential curve as shown below. In this graph besides the half-life lessenings as the concentration decreases.
The relationship between the rate of reaction and the concentration of the reactant is exponential which means that if the concentration doubles so the rate of reaction quartets. The rate of reaction is straight relative to the concentration squared.
I have chosen to transport out the reaction utilizing colorimetric analysis because I am mensurating a sudden coloring material alteration and a tintometer will give an accurate reading of how much the coloring material has changed by. Colorimeters are really accurate pieces of equipment and can observe really little alterations in visible radiation absorbency which is much more accurate than seeking to see the coloring materials alteration by sight.
I am traveling to graduate the H peroxide because H peroxide is known to degrade in the bottle into O and H2O. which means the concentration written on the bottle is non the true value. Calibrating the H peroxide will guarantee that the right concentration of H peroxide is used.
I have decided to do the amylum solution because this will be more accurate than utilizing starch solution from a bottle which may be contaminated from old usage. By doing my ain solution I will easy be able to alter the volume or concentration of the amylum solution depending on the consequences of my preliminary experiment. this will guarantee that I obtain consequences that are every bit accurate as possible.
The Arrhenius equation is used to demo how the rate changeless alterations when the temperature alterations or when the activation energy is changed by adding a accelerator.
The Arrhenius equation is shown below:
K = Ae- ( EA/RT )
K is the rate invariable
EA is the activation energy
T is the temperature ( in Ks )
Roentgen is the gas invariable ( 8. 31JK-1mol-1 )
A is apporoximately changeless. and is taken as changeless over little temperature ranges. vitamin E is a mathematical entity.
The equation above can be rewritten to read:
Ln K = c – EA ( 1/t ) Roentgen
When this equation is plotted on a graph. it produces a consecutive line graph which can be used to work out the activation energy. In this graph the gradient is represented by ( EA/R ) because this corresponds to ‘m’ in the general equation for a line – Y = maxwell + degree Celsius.
Background of Chemicals:
Hydrogen peroxide has the chemical expression H2O2 and it as a pH of 4. 5 this is the simplest compound with a individual oxygen-oxygen bond and is hence known as peroxide. The physical visual aspect of H peroxide is that it is a clear liquid that appears colorless in dilute solutions and it is a somewhat thicker consistence than H2O. Hydrogen peroxide is a extremely reactive O species and this belongings makes it ideal to utilize in bleaches or other cleansing agents. it can besides be used as a propellent in rocketry. Hydrogen peroxide is a byproduct of oxidative metamorphosis in beings and most living species have enzymes known as catalyse peroxidases. which are used in the decomposition of low concentrations of H peroxide into H2O and O.
The expression for H peroxide is below:
When a bottle of H peroxide is left in the presence of visible radiation it undergoes decomposition. for this ground H peroxide is kept in a brown bottle in a cool topographic point. Due to this nature of H peroxide. it will be titrated with K permanganate to happen out it’s true concentration and so it will be diluted to the needed sum.
The merchandises that hydrogen peroxide give off when it decomposes are H2O and O which are shown in the reaction below:
2H2O2 ( 2H2O + O2
Hydrogen peroxide decomposes at a rate which is related to the temperature and the pH of the chemicals within the reaction. Acid can be added to the solution of H peroxide to stabilise it because H peroxide is incompatible with many substances that have the ability of to catalyze the reaction. passage metals and their compounds inclusive.
In this reaction the iodide ions come from the inorganic compound K iodide which has the chemical expression KI. Potassium iodide is a white salt that is less hygroscopic than Na iodide therefore it is easier to utilize. Potassium iodide is commercially used for medicative intents such as protecting the thyroid for radioactive I. it is besides used in radiation sensors and Geiger counters.
The structural expression for K iodide is shown below:
Positive H ions are a proton that hydrates readily they can non nevertheless exist freely in solution. They are formed when atomic H loses an negatron and forms a positive ion and they are found in all aqueous solutions of acids. Hydrogen ions are formed when an negatron is removed from a H atom. which leaves a individual proton because H merely has one negatron. Hydrogen ions are really reactive and therefore can merely be in an environment that is virtually particle free such as a vacuity or in its gaseous province.
Sodium thiosulphate is normally found in its pentahydrate province in which it is a colorless crystalline compound. The expression for Na thiosulphate is Na2S2O3. 5H2O and in this experiment it will be used in this province. This compound can be used to tan leather for chemical industry or it can repair movie in picture taking.
The structural expression for the pentahydrate signifier of Na thiosulphate is shown below:
Potassium permanganate had the chemical expression KMnO4 and it is an inorganic chemical compound. This compound is besides known as permanganate of potassium hydroxide or Condy’s crystals and it is a salt made up of K+ and KMnO4- ions. Potassium permanganate has a strong oxidizing ability. This compound is dissoluble in H2O and gives off a strong purple colour and upon vaporization it leaves prismatic dark purple crystals. This belongings allows us to find the concentration of H peroxide because the colorless H peroxide turns somewhat pink which is the end point for this reaction.
The construction for KMnO4 is below:
Hydrogen chloride is a monoprotic acid because it merely has one proton that it is able to donate. This solution is hydrogen chloride dissolved in H2O. which is really caustic and hence must be diluted before usage. Hydrochloric acid is of course happening in stomachic acid.
Scheme and Justification:
Calculating The Rate:
The rate can be calculated by mensurating assorted things such as volume or force per unit area or an analysis of consequences can state us what the rate is.
By mensurating the volume of the merchandise that is produced. the rate invariable can be calculated. This can be done with such methods as an upside-down burette or a gas syringe in a reaction that produces a gas such as H peroxide and catalase. The O that is produced in the boiling tubing is passed through some gum elastic tube ; this so displaced the H2O in the upside-down burette or pushes the stopper in a gas syringe. This enables us to be able to mensurate the merchandise that is formed. The rate would be worked out by pulling a graph for each experiment in which the initial rate of reaction would move as the gradient of volume of merchandise produced against clip graph. The value obtained for the initial rate of reaction would be plotted against the concentration bring forthing a graph. which would state us the order of reaction. However for the Harcourt-Essen reaction. no gas is produced so the volume can non be measured.
Measuring force per unit area
A variable force per unit area is noticeable when two molecules respond together to give off a gaseous merchandise. A graph can be plotted by comparing a reaction that has taken topographic point under normal room force per unit area and a reaction that has taken topographic point under compaction. for illustration puting a spile on a trial tubing would change the force per unit area. The force per unit area would be plotted against clip and the gradient for the graph would give the initial rate of reaction. This information can so be plotted on another graph to happen the overall order of reaction.
Titration is frequently used for chemical analysis to find the concentration of a known reactant. A substance is put into a burette and is easy poured into a conelike flask. which allows for the exact sum of a reactant to be determined before the end point is reached. Small sums of the substance in burette must be taken out at intervals to guarantee that the reaction does non travel past the end point. The measurings that are made utilizing this method are the concentrations of the reactant at the minute the sample was taken out. By plotting concentration against clip. a graph can be drawn.
Colorimetery can be used to cipher the rate. For this type of experiment. taking the right size and colour of the filter is of high importance because the substance has to absorb the same wavelength of visible radiation which is being transmitted by the tintometer. This is known as the complementary colour for the colour of the substance because they are the same. During the experiment. the per centum abosorbancy is measured at certain intervals normally at approximately 10 seconds. This information can so be plotted on a graph against times that has the units of mol s-1. This can besides bring forth a standardization curve for which optical density is plotted against clip.
In this method. the conductance of a solution is measured. If the solution is aqueous so the ions in the solution can carry on electricity while the reaction is taking topographic point. By mensurating the electrical conduction. the rate of reaction can be measured. To bring forth a graph from this information. the conduction of the substance would be plotted against concentration in which the initial curve gives the initial rate of reaction.
Clock Reaction method:
In a clock reaction little sums of solutions are reacted together by adding them to a conelike flask from a burette. which produces intermediate substances and so the concluding merchandise. An index is used so that the colour of the concluding merchandise can be observed. Other substances are besides added to barricade the production of the reactant through agencies of a chemical reaction. This works because the reactant and the index to respond until the extra substance is used up. one time this had been used up the index and reactant signifier a coloured composite. The most normally used illustration of this is the iodine clock reaction in which Na thiosulphate is added to the reaction bring forthing I. Not until all the thiosulphate ions have been used up in the reaction will the I construct up.
In this experiment the clock reaction method will be used to cipher the rate of reaction. this is because the Harcourt-Essen reaction does non bring forth a gaseous merchandise and hence the first two methods are non applicable. The colorimetric analysis will besides be used to find the consequence of concentration on the rate of reaction because tintometers are really accurate pieces of equipment that can observe bantam alterations in optical density so hence they will able to observe the absorbency of the different blue colourss that are observed. The conductimetric method can non be used because an aqueous solution is non produced and hence no electrical conductivity can be detected.
• 3 burettes. burettes are extremely accurate measurement setup and therefore they are appropriate to utilize for this experiment because exact measurings of solutions are required. • 2 boiling tubings. boiling tubings are much larger than trial tubings and hence when heated. the solutions will heat more equally and there is less opportunity of the contents ptyalizing out. Boiling tubings are besides larger which makes it easier for the assorted solutions to blend decently. • A thermometer to mensurate the temperatures of the boiling tubings to maintain the trial reliable. • A tintometer. tintometers are able to mensurate the slightest colour alteration and therefore they are being used in this experiment because colour alterations of assorted strengths will take topographic point. • Cuvettes to pour the mixture into to put into the tintometer. • Stopwatch to clip how long it takes for the colour alteration to take topographic point. • Test tubing rack to keep the boiling tubing in.
• A stirring rod to stir the mixture and do certain that it is equally dispersed.
• Conical flask to keep the H peroxide in.
• Weighing graduated table to mensurate the mass of the remnant K permanganate.
• Hydrogen peroxide – 0. 3 moldm-3
• Sulfuric acid – 0. 3 moldm-3
• Sodium thiosulfate – 0. 005 moldm-3
• Potassium iodide – 0. 02 moldm-3
• Starch solution
• Ammonium molydbate ( accelerator )
• Hydrochloric acid ( monoprotic acid )
• Sulphuric acid ( diprotic acid )
• Phosphoric acid
• Potassium permanganate – 0. 1 moldm-3
Dynamicss of the Harcourt Essen reaction
Chemical reaction: H2O2 + 2I– + 2H+ > I2 + 2H2O
1. Investigate the consequence of temperature on the rate of reaction. Equipment:
• 150cm3 Hydrogen peroxide
• 100cm3 Sodium thiosulphate
• 150cm3 Sulphuric acid
• 2 boiling tubings
• Test tubing rack
• pH strips
• 3 Burettes
1. Put up 3 burettes with H peroxide. Na thiosulphate and sulfuric acid 2. Topographic point 150cm3 of 0. 300moldm-3 of H peroxide. 100cm3 of 0. 00500moldm-3 of Na thiosulphate. 150cm3 of 0. 300moldm-3 of sulfuric acid and H2O into a boiling tubing and label this A. Using a boiling tubing will guarantee that all the constituents are assorted and heated every bit. 3. The boiling tubing will so be placed in a trial tubing rack. 4. Measure and record the temperature each clip. The temperature must be kept changeless in every experiment to maintain the experiment reliable. 5. Following. pipette 2cm3 of K iodide into a different boiling tubing and label it B. 6. Pour boiling tubing B into the other A and instantly get down the timing from the clip the solution is added. 7. Stir the mixture.
8. Stop the clip when the first bluish coloring material appears and enter the clip in the tabular array of consequences. 9. After the reaction coatings. look into the pH and record it down to guarantee that the pH is kept changeless in each experiment. This ensures a dependable trial. 10. Repeat the reaction three times. This helps to cut down anomalousnesss and gives an accurate set of consequences. with the experiment being a just trial. If there are is an anomalous consequence. reiterate the reading. 11. Following. secret plan a graph for the clip against the concentration for each set of ( averaged ) consequences. A tangent will so be drawn on the first portion of the graph. The gradient of this tangent will give the initial rate of the reaction. Making this for each set of consequences will give initial rates for all of the experiments. 12. These would so be plotted against concentration. leting the order of reaction to be found.
2. Determine the activation heat content with and without the accelerator ammonium molybdate ( VI ) and with different protic acids and utilize this to compare the effectivity. Equipment list:
• 3 Burettes
• 150cm3 Hydrogen peroxide
• Starch solution
• Sodium thiosulphate
• 150cm3 sulfuric acid
• 2 boiling tubings
• Stop ticker
• pH strips
1. Put up 3 burettes
2. Topographic point 150cm3 of 0. 300cm-3 solutions of H peroxide. starch solution. Na thiosulphate. 150cm3 of 0. 300moldm-3 sulfuric acid and H2O into a boiling tubing and label this A. The lone concentrations that alteration are the volumes of H peroxide and H2O. The entire volume stays the same. 3. Measure and record the temperature of the boiling tubing. The temperature must be kept changeless in every experiment to maintain the trial reliable. 4. Following. pipette 150cm3 of 0. 0200moldm-3 of K iodide into another boiling tubing label this B. Making this will halt the reaction taking topographic point before it is required. 5. Calibrate and reset the tintometer utilizing a cuvette filled with distilled H2O. This will maintain the trial reliable because it will do certain the tintometer has non been tampered with. 6. Pour the solution from boiling tubing B into boiling tubing A and instantly get down clocking from the 2nd the solution is added. 7. Quickly reassign some of the solution from the boiling tubing to the cuvette and topographic point this into the tintometer 8. Every 10 seconds measure the per centum absorbency of the solution. and record this in a tabular array. 9. Stop after 120 seconds.
10. After the reaction coatings. look into the pH and record it down to guarantee that the pH is kept changeless in each experiment. this makes the trial reliable. 11. Repeat the reaction twice for each accelerator. This helps to cut down anomalousnesss and gives an accurate set of consequences. If there are any anomalous consequences. reiterate the reading. 12. Following. secret plan a graph for the clip against the % absorbency for each set of ( averaged ) consequences. A tangent will so be drawn on the first portion of the graph. The gradient of this tangent will give the initial rate of the reaction. Making this for each set of consequences will give initial rates for all of the experiments. 13. These would so be plotted against concentration. leting the order of reaction to be found.
3. Determine the effects of the presence of ethyl alcohol on the rate equation. Method: Titration
2MnO4- ( aq ) + 5H2O2 ( aq ) + 6H+ ( aq ) ( 2Mn2+ ( aq ) + 5O2 ( g ) + 8H2O ( cubic decimeter )
1. Dissolve 8. 3g of K permanganate into 200g of H2O in a beaker. 2. Fill a beaker with H2O and so add 30g of H peroxide and 10g of concentrated sulfuric acid. 3. Using a burrette. add potassium permanganate into the acidified H peroxide and halt when the purple colour is relentless. 4. Once the purple colour is relentless. take out the staying K permanganate and weigh how much is left over. 5. Use the computation described in ‘How techniques Work’ to happen out the concentration of the H peroxide. 6. Transport out the I clock reaction mentioned in the above method to transport out the experiment. 7. Repeat the experiment 3 times with ethyl alcohol and 3 times without ethyl alcohol. This keeps the experiment dependable and reduces the opportunities of anomalous consequences.
4. Investigate the order of reaction with regard to hydrogen peroxide. iodide and acid. Equipment:
• Starch pulverization
• 3 burettes
• 50cm3 Sulphuric acid
• 50cm3 Na thiosulfate
• 50cm3 Potassium iodide
• Conical flask
• Stop ticker
1. Fix a starch solution utilizing 20g of amylum pulverization and 100 cm3 of H2O. once the amylum pulverization has dissolved boil the solution. 2. Put up 3 burettes with 50 cm3 of sulphuric acid. one with 50 cm3 of Na thiosulfate and the 3rd with 50 cm3 of K iodide. 3. Measure out 10. 0 cm3 of sulphuric acid 6. 0 cm3 of Na thiosulfate. 25. 0 cm3 of K iodide 1. 0 cm3 of starch solution and 4. 0 cm3 of H2O into a little beaker. 4. Pour 10. 0 cm3 of H peroxide into a conelike flask. 5. Pour the contents of the little beaker into the conelike flask and instantly get down the stop watch. 6. Stop the timer when a sudden colour alteration is observed and enter the clip taken. 7. Repeat the above stairss 4 times and each clip dilute the solution being investigated following a tenfold consecutive dilution. 8. Plot a graph for concentration against clip. pull a line of best tantrum and find the order of reaction.
2. Investigate the rate equation. rate changeless and possible mechanism for this reaction. Method:
The rate equation can be worked out with the Arrhenius equation and the rate changeless and mechanism can be found by plotting a graph.
3. Determine how the presence of a accelerator changes the mechanism of the Harcourt-Essen reaction and whether the mechanism is effected by monoprotic. diprotic or tripotic acids. Equipment:
• 3 burettes
• 50cm3 sulfuric acid
• 50cm3 Na thiosulphate
• 50cm3 K iodide
• 1cm3 starch solution
• Conical flask
• Stop ticker
1. Put up 3 burettes with 50 cm3 of sulphuric acid. one with 50 cm3 of Na thiosulfate and the 3rd with 50 cm3 of K iodide. 2. Measure out 10. 0 cm3 of sulphuric acid 6. 0 cm3 of Na thiosulfate. 25. 0 cm3 of K iodide. 1. 0 cm3 of starch solution and 4. 0 cm3 of H2O into a little beaker. 3. Add 10. 0 cm3 the solution being investigated into the little beaker. 4. Pour 10. 0 cm3 of H peroxide into a conelike flask. 5. Pour the contents of the little beaker into the conelike flask and instantly get down the stop watch. 6. Stop the timer when a sudden colour alteration is observed and enter the clip taken. – Repeat the above stairss for all the different accelerators and protic acids being investigated. – Work out the mechanism for each experiment.
5. To happen out how the concentration of iodide ions and peroxodisulphate ( VI ) ions affects the rate of reaction. Equipment:
• 3 burettes
• 50cm3 Sulphuric acid
• 50cm3 Sodium thiosulphate
• 50cm3 Potassium iodide
• 1cm3 Starch solution
• Stop ticker
1. Put up 3 burettes with 50 cm3 of sulphuric acid. one with 50 cm3 of Na thiosulfate and the 3rd with 50 cm3 of K iodide. 2. Measure out 10. 0 cm3 of sulphuric acid 6. 0 cm3 of Na thiosulfate. 25. 0 cm3 of K iodide. 1. 0 cm3 of starch solution and 4. 0 cm3 of H2O into a little beaker. 3. Pour 10. 0 cm3 of H peroxide into a conelike flask. 4. Pour the contents of the little beaker into the conelike flask and instantly get down the stop watch. 5. Stop the timer when a sudden colour alteration is observed and enter the clip taken. 6. Repeat the above stairss 4 times and consecutive dilute the solution being investigated following a tenfold dilution each clip. 7. Plot a graph for concentration against clip and work out the rate of reaction.