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

The aim of this investigation is to see how the concentration of sodium thiosulphate when added to hydrochloric acid affects the rate of the reaction.

Extracts from this document...


Aim: The aim of this investigation is to see how the concentration of sodium thiosulphate when added to hydrochloric acid affects the rate of the reaction. The reaction that takes place is Na2S2O3 (aq) + 2Hcl(aq) S (s)+ 2NaCl (aq) + So2 + H2O Sodium + Hydrochloric Sulphur + Sodium + Sulphur Thiosulphate Acid Chloride Dioxide Theory: In this experiment when the hydrochloric acid is added to the sodium thiosulphate, each of the liquids particles will collide with each other and bonds will be broken. When the concentration is higher the rate of reaction will be quicker, this is because when the concentration is higher there will be more particles and therefore bonds will be broken quicker as there will be more collisions. The rate of reaction is the speed at which, in this case the two liquids, hydrochloric acid and sodium thiosulphate react with each other. In this experiment we will measure the rate of reaction by placing a flask on top of a piece of paper with a black cross on it. Then we will add the two liquids to the flask and time the reaction until the black cross can no longer be seen. This happens because the reaction becomes murky and turns gradually opaque. There is a minimum amount of energy that particles need in order to collide with each other and react. ...read more.


* 2 x 50cm� measuring cylinder- 1 for measuring the thiosulphate and the other for measuring the amounts of water. Accurate enough to make results reliable. * Sodium Thiosulphate- To use in the experiment. * Hydrochloric acid- To use in the experiment. * Safety goggles- For safety reasons. * Stopwatch- To time the experiment. Accurate to 100th second. Time will be rounded up to nearest 10th of a second to eliminate human errors when timing. Fair Testing and Reliability To ensure that the test will be fair and reliable I will do the following: 1. Use the same cross underneath the beaker. 2. Use all the same apparatus. 3. Take all of my readings on the same day to avoid a possible temperature change if I took them over two periods that could affect the results. 4. Always use the same person to start and stop the stopwatch as different people may have different reaction times. 5. Take all the Thiosulphate and Hydrochloric acid from the same batch to avoid slightly different concentrations. Method: * Collect and set up the apparatus as stated above. * Place the conical flask on top of the piece of paper and then add 5cm� of hydrochloric acid to the flask. * Measure out, initially, 50 cm� of Sodium Thiosulphate and then add this to the hydrochloric acid. * Swirl the flask and then begin timing immediately. ...read more.


Naturally, the above means that the graphs plotting rate against concentration has positive correlation as the concentration is increased so does the rate of reaction. This is because when the temperature is increased the particles will have more energy and thus move faster. Therefore they will collide more often and with more energy. When solutions of reacting particles are made more concentrated there are more particles per unit volume. Collisions between reacting particles are therefore more likely to occur. Evaluation: In my opinion the experiment was a very big successful. I obtained a substantial quantity of very accurate results from which I was able to create informative graphs. I obtained a good amount of results. However if I was to repeat the experiment I would also test the effect of temperature on the reaction time. The range of concentrations was well chosen. This made my results more accurate and allowed me to make greater assumptions from my results. I felt my method was well thought-out and provided fair and reliable results. To make my results more accurate I could have measured the volumes of liquids more accurately. If I were to repeat the experiment I would have possibly found a more accurate way to measure out the solutions and to determine the concentrations. All my results followed the set pattern, but some were not as close to the line as others (slightly anomalous results). This could have been caused by human errors. Overall I was extremely pleased with my results. ...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.

    + 2HCl(aq) -> 2NaCl(aq) + S(s) + H2O(l) + SO2(g) Water was also produced in the reaction even though I could not tell it was produced. I also found out that the rate of which the Sulphur was produced varied due to the concentration of the sodium thiosulphate.

  2. The aim of the investigation is to examine the kinetics involved in the reactions ...

    Each rate-determining step has highest activation energy in the reaction. Therefore it determines the overall rate of the reaction. Prediction: As the hydrochloric acid has pre-dissociated previously, increasing the concentration of solute will not have an overall effect on the actual order of the reaction.

  1. Enzymes - show how substrate concentration affects the rate of reaction for an enzyme ...

    n r = Sxy SxxSyy OR Sxy = ? (xi - x) (yi - y) Sxx = ? (xi - x) � Syy = ? (yi - y) � r = Sxy = ? (xi - x) (yi - y) V (SxxSyy) V ? (xi - x) � ?

  2. An investigation into how surface area affects the rate of reaction

    I repeated the results 3 time so that I can spot any anomalies due to inaccuracies. In order to keep a fair test, only the surface area (i.e. size) of the marbled chips is variable. Other variables are to be kept constant to avoid obtaining wrong results.

  1. An investigation to see the difference in the rate of reaction when catalyse is ...

    In my preliminary work I also tested the gas that was being produced with a burning and the burning splint flared up and the flame grew and then died down. This is the test for oxygen and the test came out positive.

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

    Plan After the preliminary experiments, I now have results which can influence my decisions on how to perform the main experiment. I will draw a thick black cross on a piece of paper. This will act as a visual marker to let us know when the reaction has occurred.

  1. An investigation into the effect of concentration on the rate of chemicl reaction ...

    thiosulphate solution in the experiment and also to find out what concentration of Hydrochloric acid should I use for my investigation. The result shows that 0.1 M and 0.2 M concentration of Hydrochloric acid with 0.3 M of sodium thiosulphate, there were no reaction as this take too long for cross to disappear.

  2. Investigation to see how the concentration affects the rate of reaction.

    product molecule and the enzyme whose reactive site can now be re-used by another reactant molecule. Below is a picture of this reaction: KEY: E = free enzyme EP = enzyme product complex S = free substrate reactant molecule E = free enzyme ES = enzyme reactant complex P =

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