• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigating the Factors Affecting the Rate of Reaction for the Iodine Clock

Extracts from this document...

Introduction

Science Coursework: Investigating the Factors Affecting the Rate of Reaction for the Iodine Clock Contents Introduction Scientific Theory Strategy (Plan) Results Analysis Evaluation References Introduction I am going to investigate how reaction rates in the iodine clock are affected. To do this I will consider the four possible independent variables: concentration, surface area, temperature and catalysts. I will then choose one factor and carry out a number of experiments, only changing that variable, and record the reaction speed. This will show how the reaction speed differs when the variable is altered. I predict that as the concentration of the Hydrogen Peroxide increases, the reaction rate will decrease. I think this because if there are more hydrogen peroxide particles to react with the other particles, the reaction will happen sooner. Theory The theory of the experiment is partly explained by the collision theory. The reaction can only take place when particles collide with enough energy. If there is not enough energy the reaction will not happen and the particle will bounce away again. The rate of a reaction depends on the number of successful collisions in a given amount of time. ...read more.

Middle

Using a burette, measure out the following amounts: * 30ml Potassium Iodide * 5ml Sodium Thiosulphate * 10ml Sulphuric Acid * 10ml Starch 2. Pour the chemicals into a conical flask 3. Using a burette, measure 30ml of Hydrogen Peroxide and add this to the conical flask. 4. Use the stopwatch to time how long the solution takes to change colour. 5. Repeat the experiment using 25ml of Hydrogen Peroxide and 5ml of deionised water, 20ml of Hydrogen Peroxide and 10ml of deionised water, 15ml of Hydrogen Peroxide and 15ml of deionised water and 10ml of Hydrogen peroxide and 20ml of deionised water. Repeat each experiment three times. Results Time of Reaction in Seconds Concentration of Hydrogen Peroxide (m) Test 1 Test 2 Test 3 Mean 0.1 326 24 23 23.5 0.083 36 36 34 35.3 0.067 42 40 41 41 0.05 60 (went yellow) 60 57 59 0.03 87 83 86 85.3 The first experiment contains an outlier because I was using a different hydrogen peroxide solution with a significantly lower molarity. This led to the time being much longer than the other results so I will discount this result from all averages. ...read more.

Conclusion

My results were very consistent and showed what I expected, so they are likely to be accurate, meaning my conclusions are likely to be accurate. I had one outlier, which was because I used a different hydrogen peroxide solution. I didn't have any other outliers which suggests the method and apparatus was accurate. However in one experiment it turned yellow, instead of the purple colour that occurred in every other experiment. I don't know why this was, but it is possible that I included the wrong amount of one of the chemicals. As the time was similar to the times recorded in the other experiments, I still included this in my results. Another way in which I could have improved my investigation would have been to investigate more than one factor and then compare the results. The title of the investigation was "Investigating the Factors Affecting the Rate of Reaction for the Iodine Clock" so by considering more than one variable I could have investigated this further. I would still have been unable to investigate surface area or catalysts but I could have carried out similar experiments to the ones I did, altering the temperature each time. This way I could have seen if the temperature affects the reaction more or less than the concentration. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Patterns of Behaviour essays

  1. Rates of Reaction - The Iodine Clock

    [A] Doubling the concentration of reactant B quadruples the rate ?second order w.r.t. [B] The rate equation for this reaction can therefore be written as: Rate of Reaction ? [A]1[B]2 = k [A] [B] 2 The overall order would be equal to three.

  2. The Iodine Clock Investigation

    is equal to the power to which the concentration of this species is raised to (a, b or c) The overall order of the reaction is equal to the sum of the powers of the concentration. Order = a + b + c Where the rate expression shows the reaction

  1. The Iodine Clock

    the thiosulphate increased the time of that it took for the cross disappear also increased which is different to my prediction, although it can be explained. Prediction 2: I predict that the thio will slow down the experiment as when its concentration increases there is less iodine being produced, unlike the other substances; when Sodium thiosulphate (Na2S2O3)

  2. Investigate the factors affecting the rate of a reaction.

    1.0 molar hydrochloric acid and the slowest, sodium thiosulphate with 0.2 molar solution of hydrochloric acid. Since the rate of reaction increases as the concentration increases I will expect the rate of reaction graph to have a reasonably strong, positive correlation and the time graph a strong negative correlation.

  1. A-Level Investigation - Rates of Reaction – The Iodine Clock

    The order with respect to a particular reagent is known as a singular order, however, the overall order of a reaction is found by adding together all the singular order involved. E.g. In the reaction A + B --> C Doubling the concentration of reactant A doubles the rate ?First order w.r.t.

  2. Investigation Into the Factors Affecting Rate of Reaction

    my experiment at around 20cm� Beakers- I will use these to pour the raw chemicals into. They will be 250cm� as I will not need any bigger and smaller would be unsafe. Conical Flask- This is the piece of equipment where the apparatus will take place.

  1. Factors Affecting Enzyme Activity

    I put a rubber bung on the boiling tube which had a hole in the top allowing me to put a syringe through it meaning that the reaction was completely contained in a sealed unit so any gas given off would only go into the measuring cylinder.

  2. Find out how the rate of hydrolysis of an organic halogen compound depends on ...

    If this spill is on the clothes then the contaminated clothing should be removed and put outside. If the spill is not in any of these areas but in the laboratory then the area of the spill should be ventilated as soon as possible.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work