• 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...

Introduction

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.

Middle

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.

Conclusion

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. Marked by a teacher

    To see how the concentration of acid, reacting with potassium carbonate, affects the rate ...

    4 star(s)

    continue to react and because there are fewer particles in the volume there is a lower chance of a successful collision, so the reaction produces less CO2 per 10 seconds so it slows down gradually resulting in a curve. From my graphs I can say that the reaction rate does not double if concentration of acid doubles.

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

    My dependent variable is the rate of reaction and the hydrochloric acid used. My controls are: Temperature; the temperature affects the rate of reaction as the reaction is faster at a higher temperature. In order to keep the temperature the same I will leave my solutions in the room before

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

    So I determined my results by trying to make a conscious decision about all of them as fairly as possible. \ Analysis The Graph:- *** *** After drawing my first graph, I realised that I could not interpret it because I could not see if there was a relationship between them or not.

  2. Investigation to find out; what happens to the rate of reaction when you change ...

    RESULTS CONCLUSION I have found out that as concentration of the Hydrochloric Acid gets higher the rate of reaction gets lower, this is because if the solution is more concentrated it means there are more particles of reactant in between the water molecules, which makes collisions between important particles more likely.

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

    The syringes will all be clearly labelled and will not be used for any other things to avoid contamination. The apparatus was set up as shown in the diagram below. Risk assessment: Amylase can be an irritant so I will wear plastic goggles to protect my eyes and use a spatula when handling it and take care.

  2. Rates of Reaction

    is a much smaller collision frequency this means that there is less chance of an acid particle colliding with the calcium carbonate molecule due to the concentration. B) In flask B the acid is much more concentrated (simply meaning that there are much more acid particles contained in it).

  1. Rate of Reaction

    The reacting molecules however have to overcome the activation energy to react and if the activation energy is high then only the most energetic molecules will be able to overcome it making the reaction slower. If, however, the activation energy is small then more of the collisions will be effective and the reaction will be faster.

  2. 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

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