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

Investigating how concentration affects rate of reaction

Extracts from this document...


Lindsay Newell Investigating how concentration affects rate of reaction Planning Introduction The experiment I am doing to change the rate of reaction is: Sodium thiosulphate + Hydrochloric Acid � Sulphur + Sodium Chloride +Sulphur Dioxide + Water Na2S2O3 (aq) + 2HCl (aq) � S (s) + 2NaCl (aq) + SO2 (g) + H2O (l) Possible ways of changing the reaction time are: * Changing the concentration, if you increase the concentration there will be more collisions because there are more particles in the same volume, * Changing the temperature, if you increase the temperature it will make reactant particles move faster and collide more often, * If a catalyst is present, it will speed up the reaction. I will be changing the concentration because it is the most suitable thing to do. Aim For this experiment I am changing the concentration of Sodium thiosulpate to alter the reaction time for the reaction between sodium thiosulphate and hydrochloric acid. Hypothesis I am going to change the concentration of sodium thiosulphate by adding water to it. By doing this it should take longer for the mixture to go cloudy. Fair test To make my test fair I will have to make sure: * The concentration and volume of hydrochloric acid stays constant, * The outside temperature is constant, because if it is too hot and heats up my experiment the particles in the chemicals will move faster making them collide more often. ...read more.


Concentration of Sodium thiosulphate when water is added (g/dm�) Time taken Temperature (�C) 40 30.28 sec 26 35 35.25 sec - 30 44.47 sec - 25 51.94 sec 26 20 1 min 3.53 sec - 15 1 min 34.93 sec - 10 2 min 35.29 sec - 5 6 min 16.09 sec 26 In my preliminary I did what I described in my method and used all of the volumes and concentrations I stated, I think my preliminary test went very well although there are a few things I will do to retrieve exact results. When I did the preliminary I found what I guessed in my prediction and what I will be able to explain in more detail after my real experiment, but I found that the lower the concentration of sodium thiosulphate the longer the time. With my preliminary results I came across a few problems, the cross on the paper got wet and the cross faded every time I repeated the experiment. To fix this I could: make photocopies of the same cross for every repeat, wipe the bottom of the flask dry after each time I rinse it out and be careful when pouring chemicals or I could draw an "X" and have it laminated. I think I will just wipe the bottom of the flask each time as if I photocopy the "X" the machine could be running low on ink and make the second "X" fainter then the first. ...read more.


the inside to make sure the excess water did not affect the experiment, I noted down the size of all the beakers and measuring cylinders as well. If I had used a different sized beaker it would have made a large difference, say I had used a larger beaker instead that would men that the chemicals would be more spread out so the reaction would take place and the cross would have taken longer to disappear. The opposite would happen with a smaller beaker. I did not get anomalous results because the graph was a curve. I chose to use a curve because it looks better and the results would not fit a line of best fit. The only thing I will say about my curve it there is quite a large gap between the points at 30 and 35. This could be because there is suddenly not a lot of sodium thiosulphate to react with the hydrochloric acid. It also could have been because of a mistake I made, but it happened in every experiment I did including the preliminary. Further work to do on the experiment would be to research a wider variety for results and compare them with what I have already done or test another way of altering the reaction time of sodium thiosulphate and hydrochloric acid. By doing this I could see if it is quicker to do it by changing the concentration or the new method, and I could also see which one was more accurate. ...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.

    This would allow them all to reach the same temperature. Then after 15 minutes I would take them out and mix them and then put them back in for another 15 minutes. This would mean that the enzymes had reached their optimum temperature for working and then had been giving 15 minutes to work.

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

    the experiment for 2 hours so they can adjust to room temperature. Same conical flask used; this is so that it is a fair test so I can compare the result with the results from other experiments conducted in the same conical flask.

  1. Rates of Reaction

    Catalyst The word catalyst means an added substance, in contact with the reactants, that changes the rate of a reaction without itself being chemically changed in the end. Catalysts increase the rate of a reaction by helping break chemical bonds in reactant molecules and provide a 'different pathway' for the reaction.

  2. Rate of Reaction

    For example if sodium thiosulphate was heated at 20oC the movement energy in the particles is less, and is more likely to be below the activation energy whereas at 60oC the movement energy in the particles is higher, making it more likely to be above the activation energy.

  1. to investigate how the concentration affects the rate of the reaction

    PREDICTION In my experiment, I predict that if I change the concentration of the hydrochloric acid (by adding water to make it dilute) the rate of the reaction will be slowed down. This is because by adding water to the acid, the number of particles that will react with the

  2. Rate of Reaction between Sodium Thiosulphate and Dilute Hydrochloric acid

    out the balanced equation so I knew what the reaction would give me at the end and I used my text book: Chemistry for AQA(Heinemann) by Ann and Patrick Fullick to help me back my prediction with solid scientific knowledge.

  1. The effects of concentration on reaction rate with sodium thiosulphate

    acid into the conical flask first, and the water, and sodium thiosulphate at the same time, second. * After each experiment I will clean the conical flask, so the results can be fair. While carrying out the experiment I will always need to think of them points if I want to keep the experiment exact and accurate.

  2. I am investigating how the effect of concentration has on the rate of reaction ...

    what volume and concentration should then be used to get the optimum results. The concentration of the Sodium Thiosulphate that was used in the preliminary experiment was 0.003M which was weak; the volume of the sodium thiosulphate and the hydrochloric acid was too low.

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