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

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

Extracts from this document...


What Affects the Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid? By Will Lilley 14-3-10 What affects the rate of reaction between Sodium Thiosulphate and Hydrochloric acid? By Will Lilley Aim I plan to find out how the rate of reaction between Sodium Thiosulphate and Hydrochloric acid can be sped up or slowed down depending on the concentrations. Introduction To know what affects the rate of reaction in an experiment, we must first know how to calculate the rate of reaction. This is done by dividing 1 by the amount of time taken for the reaction to have completed. The rate of reaction is driven by the collision theory, which states that "When two chemicals react, their molecules have to collide with each other with sufficient energy for the reaction to take place." http://www.purchon.com/chemistry/rates.htm There are also four factors which could affect the rate of a reaction, according the collision theory: Temperature, concentration (of the solution), pressure (in gases), and the surface area of the solid reactants. By the end of the experiment, I hope to have proved that when the concentration of the solution is increased, the rate of reaction increases, because there are more molecular collisions. I am going to measure the rate of reaction that occurs when I mix sodium thiosulphate and hydrochloric acid. A product of this reaction will be sulphur in the solution, which will make it go cloudy. This is shown by: Sodium Thiosulphate + Hydrochloric acid �Sodium Chloride + Water + Sulphur Dioxide + Sulphur Na2S2O3 (aq) + 2HCl (aq) � 2NaCl (aq) + H2O (l) + SO2 (g) + S (s) ...read more.


I drew a thick black cross on a piece of paper. I then created a reaction table, seen below, which I could follow as I was performing the experiments. I placed these amounts into a conical flask (which was placed on the cross) and used a stopwatch to record how long it took for the reaction to turn to a cloudy white colour. When I could no longer see the cross, I stopped the stopwatch and recorded how long it had taken for the reaction to take place. Once this had been done, I washed the beaker out and started again with the next amount. It is possible that my measuring of the liquids could have been more accurate, and there may have been some time lapse problems using the stopwatch. Measuring the liquid using pipettes may have been more consistently accurate. Results Here is my table of results from the experiments. It involves the three experiments that we did, along with the average time and the average rate of reactions: If we look at the average time (in seconds) column, we can see that each experiment's reaction time gradually decreases. However, as we can see from the table, there is an evident outlier between the times gathered from the 25cm3 (of thiosulphate) experiment and the 30cm3 experiment (51.67 value). This can also be seen on my graph, as the 30cm3 experiment does not fit into the line of best fit. On my graph (appendix 1) I have plotted the average rates of reaction and used the rates for the upper and lower time values to calculate other rates. These can be seen in the table below. I have used these calculations to build error bars into my graph. ...read more.


There are several reasons for this; A pattern was clear from my graph (an upward sloping straight line suggesting a strong positive correlation between volume and rate of reaction) and from the table of figures even with outlying values. We would need to repeat the experiments again several more times to improve reliability but if my theories in section (B) above are correct, then the overall conclusion would seem to be sound. With more time I should also like to have done an experiment where I varied the volumes of acid and kept the thiosulphate constant to cross-check the results and ensure reliability. The graph suggests that a fair degree of reliability in my results. My line of best fit passes within the error bars of most of the points plotted. According to the table in my results section, the average reaction time falls steadily with an increase of thiosulphate and the average rate of reaction increases with increased levels of thiosulphate. This suggests that the results have an acceptable level of accuracy and thus the conclusion is reliable. I have tried to investigate my conclusion in more detail by calculating the gradient of my line of best fit. Using my knowledge that the equation of a straight line graph can be expressed as 'y=mx+c', I can show that the equation of my line is 'y=0.088 x - 0.26'. Therefore, the expectation that rates of reaction would double with twice the volume of thiosulphate was inaccurate. However, this equation does give me the ability to forecast the reaction for any given volume of thiosulphate. To improve the reliability of my conclusion I could redo the experiments and make predictions about the rates of reaction using my graph. If my predictions were correct, this would show that my conclusions were correct. ?? ?? ?? ?? ...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. Experiment to Investigate the Rate of Reaction between Hydrochloric Acid and Sodium Thiosulphate, with ...

    From my results and observations I made adjustments and modifications to my method to make my results more accurate. The changes I made were as follows: * I doubled the volume of hydrochloric acid added to the reaction from 5cm� to 10cm� as the time taken for the precipitate to

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

    This must be done as quickly as possible as you want as little heat to be lost as possible. Once the time has been recorded you then wash out the conical flask with water. You then repeat the test with either a different temperature water bath or the same, remembering

  1. Investigate the rate of a catalysed reaction, when altering the temperature of the solution ...

    If I took a sample that roughly, but not exactly the same colour as the iodine and then after 30 seconds, took another sample, and this time it was identical as the colour of

  2. How does the Temperature affect the Rate of Reaction between Sodium Thiosulphate and Acid?

    molecules will be effective and then the collisions will be able to overcome the EA, making the reaction faster. Also when the collisions are relatively gentle, there isn't enough energy available to start the bond-breaking process, and so the particles don't react.

  1. Experiment to investigate how changing the concentration of hydrochloric acid affects the rate of ...

    * If I use 100ml of hydrochloric acid it would be much easier for me to change its concentration. I will explain how to do this later. As mentioned earlier, the hydrochloric acid breaks down the calcium carbonate into three different substances: Carbon dioxide, Calcium chloride and water.

  2. Rates of Reaction experiments

    be slower but when the temperature is raised to a higher degree the magnesium strip will react with HCl much faster. So when the particles move faster they would have more collisions between them. In cold temperature In hot temperature Example when magnesium strip is set to react with HCl

  1. Find out how the concentration of the reactants affects the rate of reaction between ...

    I will then look down the flask to look at the cross until I cant see the cross no more and at that point where I cant see the cross any more I will stop the stop clock straight away. I will then record the time down in my book.

  2. Investigate how temperature affects the rate of reaction in the reaction of Sodium thiosulphate ...

    time taken was 9.12 seconds, from theses results you can clearly see that the reaction was speeded up. The results that I have obtained support my original prediction. This is because in the prediction I said that the longer I heated the Sodium thiosulphate the faster the reaction would take place.

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