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

Investigation into how the concentration of Sodium thiosulphate affects the rate of reaction.

Extracts from this document...


Investigation into how the concentration of Sodium thiosulphate affects the rate of reaction In this investigation I am going to find out how the concentration of Sodium thiosulphate affects the rate of reaction when reacting with hydrochloric acid. In the experiment there are many factors that could change the reaction rate, these are; * Temperature as the higher the temperature, the faster the particles move, increasing the chance of a successful collision * Stirring the solution as it gives the particles more energy to collide with. * Concentration of the Hydrochloric acid / Sodium thiosulphate as the more particles there are in the solution, there is a higher chance of a successful collision. * The volume of the Hydrochloric acid / Sodium thiosulphate as this again increases the chance of a successful collision as there are more particles to be collided with. In this investigation I have chosen to change the concentration of the Sodium thiosulphate as it is an easy factor to change. The reaction that will be used is: In this investigation, I predict that as the concentration of the Sodium thiosulphate increased, the time taken for the reaction will decrease. I predict this because as the concentration of the Sodium thiosulphate increases there are more particles for the hydrochloric acid to collide with. The frequency of collisions increases, making the chance of a successful collision greater. ...read more.


To make the readings as accurate as possible I am going to use the teat pipettes to get the Sodium thiosulphate and hydrochloric acid as accurate to the measurements as possible. The same safety precautions are going to be used as in the preliminary work. To start the experiment take 50cm� Sodium thiosulphate and add to the conical flask. Add 10cm� hydrochloric acid and pour into the conical flask and stir once. Start timing the experiment and watch the solution to turn colour until the X underneath the conical flask and stop the stopwatch. I then repeated the same method using the ratio sodium thiosulphate : water for: 40:10 30:20 20:30 10:40 The results for the investigation are below. Vol. of Thiosulphate (cm�) Vol of water (cm�) Time taken for X to disappear 1 2 3 Average 1/t 50 0 21.68 21.5 - 21.59 0.046 40 10 24.5 23.78 2.63 23.71 0.042 30 20 33.28 32.03 - 32.66 0.031 20 30 45.59 49.97 50.5 47.78 0.021 10 40 140.62 135.4 139.22 139.92 0.0071 Looking at my results, I can see that my prediction was right and there is a clear pattern seen between the time taken and the ratio between the sodium thiosulphate. As the sodium thiosulphate decreases in concentration the time taken increases. My quantitative prediction was also true as the time taken also doubles when the concentration halves. For example, the 20:30 and the 40:10 double from 0.021 to 0.042. ...read more.


The hardest was keeping the temperature the same as it was carried out in room temperature. Also, stopping the stopwatch at the exact time is hard to do as there is a reaction time before you press the button. Some of the results had to be repeated a 3rd time. This could be because of many different factors such as timing incorrectly, spilling acid or a slight increase/decrease of acid. These factors could also be applicable to the anomalous results in my experiment. In my opinion using the average of 2 results only gives a rough idea of the time taken. To make the results more reliable, I think 5 readings would be more accurate and up to 10 concentration. To make the timing as accurate as possible I would use a light probe to measure the amount of brightness passing through the solution. When the light passing through gets dark enough, that is when the timing of the experiment stops. To keep it a fair test we would stop when an exact amount of brightness is lost through the solution. To further advance the investigation I would then do another experiment changing a different factor such as increasing/decreasing the temperature. If the temperature is increased the rate of reaction would also increase as the particles would have more energy to collide with each other, in turn increasing the successful collision rate. ?? ?? ?? ?? Mathew Howell ...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. How Concentration affects the rate of reaction.

    Volume of water (cm�) 1 50 0 2 40 10 3 30 20 4 20 30 5 10 40 I will do 5 experiments, each with a varying concentration of hydrochloric acid. This is the only variable I am changing, which means I should keep other variables the same e.g.

  2. Enzyme Investigation.

    Batch of Hydrogen Peroxide The same batch of hydrogen peroxide had been used in different concentrations throughout the experiment. This was to ensure that there were no differences in the batches made. Therefore this would give more reliable results. Surface Area of Carrot The surface area of the carrot needs to be kept the same for each of the experiments.

  1. What Affects the Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid?

    The more successful collisions there are, the faster the rate of reaction." http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/rocks_metals/7_faster_slower1.shtml To be systematic and to gain more accurate and practical results, we have also agreed that we would increase the thiosulphate amount in gaps of 5cm3, and increase the amount of Hydrochloric acid from 5cm3 per reaction to 10cm3.

  2. We will carry out an experiment to see how concentration affects rate of reaction ...

    It would be unfair if the person judging changed, because the times would alter, and this would not display the results accurately. We will also keep it in the same area, where there is little change in the light throughout the experiment, as light change would alter when we judged the cross to disappear.

  1. An investigation into how concentration affects the rate of a reaction

    - A measuring cylinder - MnO4 granules - 20 vol. H2O2 solution When fully set up, I believe the experiment should look like this: METHOD When gases are produced in a reaction, it is customary to use 'collection over water' methods to collect the gas.

  2. In this investigation I am trying to find out how the concentration of sodium ...

    We placed the conical flask onto the paper and timed how long it took for the cross to disappear. We recorded our results and then drew a graph. Paper colour Volume of sodium thiosulphate, cm� Volume of water, cm�

  1. An investigation of one factor which affects the rate of reaction between Sodium Thiosulphate ...

    You need to break bonds first and then the collisions have to be hard enough. Not all collisions are successful. They have to have enough energy to break bonds. The amount of energy they need to get over is called the activation energy.

  2. Enzyme Investigation

    There are more collisions of the acid particles and the powdered Mg, and so the Mg will dissolve faster. > Enzymes: Enzymes are biological catalyst, which are proteins in nature. Enzymes are specific they only break down one substance at a time.

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