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

Investigating the effect of temperature on the reaction between Sodium Thiosulphate (Na2S2O3) and Hydrochloric Acid (HCl)

Extracts from this document...


Investigating the effect of temperature on the reaction between Sodium Thiosulphate (Na2S2O3) and Hydrochloric Acid (HCl) Planning and Prediction Apparatus List Conical Flask 3 measuring cylinders Sodium Thiosulphate (Na2S2O3) Hydrochloric Acid (HCl) Thermometer Stop watch When sodium thiosulphate reacts with hydrochloric acid, the solution becomes opaque. I will investigate how the rate of this reaction is affected when the experiment is carried out at different temperatures. The reaction that occurs produces sulphur dioxide, water and sodium chloride. It can be shown by this equation: Na2S2O3 (aq) + 2HCl (aq) --> S (s) + SO2 (g) + H2O (l) + 2NaCl (aq) sodium thiosulphate + hydrochloric acid --> sulphur + sulphur dioxide + water + sodium chloride The rate of chemical reactions can be affected by a number of things: * changes in surface area * changes in concentration of the reactants * changes in temperature * added substances called catalysts * and changes in pressure if the reactants are gases. In most chemical reactions the rate changes with time, normally slowing down. Prediction I will be investigating the effect that temperature has on the reaction between sodium thiosulphate and hydrochloric acid. I predict that the higher the temperature, the faster the reaction will occur. ...read more.


This is because by the end of each experiment the temperature of the solution will have cooled and the temperature taken at the beginning would be inaccurate. Each experiment will be repeated at least twice and an average will be taken. This will ensure that results that are inaccurate will be noticed and the time will be as accurate as possible. The only variable in the experiment will be the temperature; the amounts of HCl, Na2S2O3, water and everything else will be kept constant. The apparatus must be carefully cleaned out after each experiment because just one drop of HCl in Na2S2O3 can contaminate it and make all the results inaccurate, as I found out in my preliminary tests. Results Desired Temperature (�C) Temperature at start (�C) Temperature at finish (�C) Time (seconds) 20 24 24 211 24 24 182 23 23 199 30 32 31 106 30 28 108 40 42 40 51 43 41 52 50 50 48 40 52 50 35 60 64 64 22 64 62 24 Averages Desired Temperature (�C) Average Temperature (�C) Average Time (seconds) Rate of reaction (1/time) 20 24 197 0.0051 30 30 107 0.0093 40 42 52 0.019 50 50 38 0.026 60 64 23 0.043 Conclusion As the temperature increases, the time for the cross to disappear decreases, so the reaction becomes faster. ...read more.


The first graph produced a good curve which did not seem to have any inaccuracies in the points. However, on the straight line graph the point for 60�C did not fit the straight line like the other points. It could be that the graph should curve up at this point. To see if this is the case I would have to take more readings, possibly at a higher temperature. The other, more likely, possibility is that the readings I took for 60�C were slightly inaccurate and although this did not show up on the first graph it showed on the second graph because the second graph used a much smaller scale. The rate of reaction appears to be too fast. It could be that the stopwatch was stopped a few degrees of a second out, or that the person watching the cross judged that the cross had disappeared too soon, or there could have been inaccuracies in the exact measurements of the sodium thiosulphate and the hydrochloric acid. Either way I would have to do further experiments to sort out the inaccuracy. To provide a more detailed pattern of results the experiments could be done at more temperatures, for instance every five degrees instead of every ten degrees like I did. My experiments showed quite successfully that temperature speeds up a chemical reaction at an increasing rate. ...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. Marked by a teacher

    In my investigation I am going to look at how concentration affects the rate ...

    3 star(s)

    Strategy for results I will find the average time taken for the "X" to be obscured by a solution of sodium thiosulphate and hydrochloric acid from 3 readings. I will record my results in a table form (as shown below)

  2. The Rates of Reaction Between HCl and Na2S2O3.

    To work out the rate of reaction, I will inverse (1/time taken) the time it takes for the reaction to finish then I will multiply the time by 1000. This will give me my rate of reaction. I will then repeat the experiment increasing the concentration of the HCl by 1cm� and decreasing the H2O concentration by 1cm�.

  1. Reaction between sodium thiosulphate solution (Na2S2O3) and dilute hydrochloric acid (HCl)

    With a greater surface area of solid there are more collisions taking place hence the reaction rate is greater. The rate of reaction increases if you increase the concentration of reactants. In dilute acids there are not so many H+ ions therefore there is not much chance of an H+ ion colliding with an atom of the other reactant.

  2. Sodium Thiosulphate - investigating the rates of reaction, and the effect different changes have ...

    The water is heated to the necessary temperature (30�C to 70�C) then the two measuring cylinders are taken out and the contents of both are poured into a conical cylinder. The time it takes for the X to disappear is timed and recorded.

  1. Safety To investigate the effect of concentration on the rate of reaction between sodium ...

    We presume that when the concentration of Na2S2O3 is increased, the rate of reaction will be higher. This is because if there are more molecules, they are more likely to collide and react. However, the collision theory states that a very small percentage of these collisions result in a reaction.

  2. Propanone reacts with Iodine slowly at room temperature. This reaction can be faster if ...

    Increasing the concentration of HCl was quite complicated, so I thought that it would be easier to decrease the concentration instead, which can easily be done by adding water, but making sure the volume stays the same. I have to consider different factors that could affect my experiment: 1.

  1. Sodium thiosulphate and hydrochloric acid Investigating how the rate of reaction is affected ...

    Thus for the reaction of two compounds (in this case X and Y) that form a product (Z) the equation would be: X + Y = Z The Rate of Reaction varies greatly. Some chemical reactions, such as explosions, happen very quickly while others like rusting occur very slowly.

  2. Investigate how temperature affects the rate of reaction of sodium thiosulphate (Na2S2O3) and hydrochloric ...

    This should be most effective for eliminating anomalous points and experimental error in the given time. Prediction/ Background Knowledge Matter is made up of particles. Substances are made up of molecules bonded together, and molecules are made up of atoms bonded together.

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