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

Rate of reaction- Sodium Thiosulphate and Hydrochloric Acid.

Extracts from this document...


Rate of reaction- Sodium Thiosulphate and Hydrochloric Acid Introduction When sodium thiosulphate and hydrochloric acid react they produce a cloudy precipitate. The two chemicals are both clear solutions and will react together to form a yellow precipitate of sulphur, the equation for which is as follows: Na2S2O3 + 2HCl ?2NaCl + SO2 + S + H2O As the solution will turn cloudy, we can observe the rate of reaction by placing a black cross underneath the beaker and seeing how long it takes for it to disappear. There are factors that affect this experiment such as temperature, concentration and time. I do not think that surface area will affect the experiment, as both chemicals are liquids. For my experiment I will study concentration as this is easily observed and can be easily varied. Prediction I think that as the concentration of sodium thiosulphate increases, the amount of time taken for a reaction decreases. I know this because before two particles can react they must meet. In a low concentration, the particles will be few and widely spread. This means that the number of reactions will be limited because less particles will meet. At higher concentrations there are more particles and so they probability of them coming into contact with other particles is increased. ...read more.


This is because if I use above 50 the results will not be affected anyway and so a substantial amount of thiosulphate is not obtainable, due to limitations on the school's resources. This is also the best range to use because in my evaluation I will need to discuss further work, and then I could use 5, 15, 25, 35 and 45 to create further results and make my experiment more accurate. Method Take a piece of paper with an "x" clearly marked on it, conical flask, measuring cylinder and timer. Measure 50cm3 of sodium thiosulphate and 5cm3 of hydrochloric acid. Add the hydrochloric acid to the sodium thiosulphate in the conical flask and gently swirl. Place conical flask on the paper with "x" marked and start the timer. Observe the reaction through the top of the conical flask and stop the timer as soon as the cross can no longer be seen. Repeat experiment with 40cm3 thiosulphate, 5cm3 hydrochloric acid and 10cm3 water. Keep repeating, adding 10cm3 less thiosulphate and 10cm3 more water each time. Record results in a table of results. Apparatus Sodium thiosulphate, hydrochloric acid and water Paper with "x" clearly marked. Conical flask Measuring cylinder Timer Results Time taken for cross to disappear (S) Volume of thiosulphate (cm3) Volume of HCL (cm3) ...read more.


Also, the human eye causes errors such as this The eye could also have made mistakes in judging whether or not the cross had actually completely disappeared If the same person watching the reaction was working the timer, errors could occur in their co-ordination. We could remove these errors by: Making sure the bottom of the meniscus is read so that it is the true reading. Using a burette to measure. This would remove the measuring errors associated with measuring cylinders, as they are correct to 0.1 cm where measuring cylinders are only 0.4. Burettes are a far more accurate way of measuring the correct amounts. Use light sensors to detect when the cross is no longer visible. The experiment could be connected to a light sensor, and to a timer. These light sensors will detect when there is no light shining through the substance. This would automatically stop the timer and therefore make the experiment fairer and more accurate. To further investigate this experiment, I could use a wider range of times. I used 10, 20, 30, 40 and 50 and so I could use the mid points of these times for more accuracy. I could also go up to 100cm3 to obtain more results but this possibly would not affect my experiment. Andy Fraser ...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 Aqueous Chemistry 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 Aqueous Chemistry essays

  1. The action of amylase and pectinase in varying amounts when clarifying cloudy apple juice.

    My results for this are shown below. 15 minute time intervals Colorimeter reading (arbitrary units) 0.9-0.1 2.65 0.8-0.2 2.55 0.7-0.3 2.55 0.6-0.4 2.55 0.5-0.5 2.6 0.4-0.6 2.65 0.3-0.7 2.6 0.2-0.8 2.8 0.1-0.9 2.8 The results shown here showed me that there was not that much clarification going on.

  2. See how long it takes for sodium Thiosulphate and hydrochloric acid to react at ...

    So for the next experiment I will change the measurement for the sodium thiosulphate so that when water is added the total measurement of the two is 50cm�. For example using 40cm� of sodium thiosulpahte and 10cm� of water. The measurement for the hydrochloric acid always stays the same for each case.

  1. What factors affect the rate pf reaction between sodium thiosulphate and hydrochloric acid?

    In order to do this I use the precipitation method. This is when I observe a cross through the solution and measure how long it takes for it to disappear. I am using this method because there is a precipitate formed between the reactants.

  2. Investigation to find out the lengths of times for a solution of hydrochloric acid ...

    These results aren't very accurate so I will have to do the experiment again with a few changes... This time I will get the same equipment and do everything the same, except I will use a wider range of solutions, varying the amount of sodium thiosulphate and water used each time, more than before.

  1. Investigate the rate of reaction between colourless solutions, hydrochloric acid and Sodium Thiosulphate by ...

    o Pour both reactants in the beaker simultaneously o The concentration of the sodium thiosulphate should also stay constant o Each experiment should also take place at room temperature o Each experiment should be repeated at least three times, to make that the results are accurate.

  2. My Aim is to see how concentration of acid will affect the time it ...

    One bad points is that I will have to be very careful with measuring out My results on the whole are what are incorporated into my prediction. Also in my pilot I decided not to stir the solution because the more you stir the more energy you give the particles

  1. To find out how the rate of reaction between sodium thiosulphate and hydrochloric acid ...

    This is because by doubling the number of hydrochloric acid molecules present the chance of a collision should be doubled, as there is now twice the possibility of a collision-taking place initially. This can be thought of as like people in an enclosed space, if there is twice the number

  2. Experiment to investigate the factors that affect the rate of reaction between sodium thiosulphate ...

    When they react, they will create a cloudy liquid. I can use this fact to test the effect of concentration on the rate of reaction. In the experiment, I have a range of molars of acid available to me. I will test 0.5, 1 and 2 molars and observe which will give me the best result.

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