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

    smaller than 2.0cm. This would in turn have decreased the rate of the reaction, as there are fewer atoms available on the solid to react with. In order to overcome this problem, a 10.0 cm strip of magnesium was cut prior using a ruler and mark off 2.0 cm with a pen.

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

    of water in order to get a concentration of 2 mol/dm�. Hence because 2 moles is: Number of moles = Mass Molar Mass Hence: 2 moles = Mass 34.0g/mol Therefore Mass = 2 moles � 34.0g/mol = 68.0g So therefore in order to make a hydrogen peroxide to a concentration

  1. An investigation into the effect of Concentration of Sodium Thiosulphate on the rate of ...

    This minimum energy level is called the activation energy. This is once a reaction has started - and therefore enough energy has been created in the collision to break the covalent bonds - and energy is therefore released from bond formation (in the products). As bond forming is exothermic, releases heat energy this energy then helps more collisions to become successful.

  2. The aim of my experiment is to see how temperature affects the reaction rate ...

    * Conical flask * 2 measuring cylinders * A sheet of paper with a cross on it * Water bath (for different temperatures) * Hydrochloric acid * Distilled water * Sodium thiosulphate * Thermometer * Stopwatch Procedure- The first thing to do is know what temperature you are going to do the chemicals at.

  1. 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.

  2. We will carry out an experiment to see how concentration affects rate of reaction ...

    We will keep exactly the same Sodium Thiosulphate and Hydrochloric Acid, so the concentration does not differ more than we control it to do. We will do this because, for example, even if we find another bottle of Sodium Thiosulphate with 2 molar concentration, it will be different from another

  1. An investigation into how concentration affects the rate of reaction between Sodium Thiosulphate and ...

    0.2 20 80 0.4 40 60 0.6 60 40 0.8 80 20 Method Firstly we measured out our first concentration of hydrochloric acid (0.2) using 20 cm3 of Hydrochloric acid and 80cm3 of distilled water. We then poured 50 cm3 of Sodium Thiosulphate into a conical flask and placed it

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

    I will measure out 4g of marble chips on a scale and put them in the flask, as soon as all the marble chips are in the flask, I will put the rubber tube in the flask and start the stopwatch.

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