• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12

How Concentration affects the rate of reaction.

Extracts from this document...

Introduction

How Concentration affects the rate of reaction I am investigating the rates of reaction and how the different variables can affect it. I know that the temperature, a catalyst, concentration, the surface area, light and pressure of a gas can affect the rate of reaction. In this particular experiment I am going to investigate on how the concentration of one of the reactants affects the rate of reaction. To show that the concentration does affect the rate of reaction I am going to carry out the reaction of sodium thiosulphate and hydrochloric acid. The reactant I am going to change in concentration for each experiment/reading is sodium thiosulphate. Word Equation Sodium + Hydrochloric � Sodium + Sulphur + water + Sulphur Thiosulphate acid Chloride dioxide Chemical Equation Na2S2O3(aq) + 2HCl(aq) -> 2NaCl(aq) + S(s) + H2O(l) + SO2(g) Equipment Sodium Thiosulphate (NaSO) of different concentrations and volumes 5cm� Hydrochloric acid (HCl) Water of different volumes Paper marked with a cross 2 Measuring cylinders Conical Flask Stopclock I will set the equipment up as shown in the diagram below Method I am going to measure out the right amount (50cm�) and concentrations of the sodium thiosulphate and hydrochloric acid. I will vary the concentration of the sodium thiosulphate but will still keep the volume of the acid the same. I will keep the volume (5cm�) and concentration (2.0 moi/dm�) of the hydrochloric acid the same. The table below shows the amount of water I will add to the sodium thiosulphate to vary the concentration in each experiment. Experiment Number Volume of 0.15 mol/dm� sodium thiosulphate (cm�) Volume of water (Cm�) Concentration sodium thiosulphate solution (mol/dm�) 1 50 0 0.15 2 40 10 0.12 3 30 20 0.09 4 20 30 0.06 5 10 40 0.03 I will pour the right amount and concentration of sodium thiosulphate (varies in each experiment No.) in the conical flask, which is on the cross that is marked on the paper. ...read more.

Middle

By doing 4 sets of results I could spot anomalous results and I can find out why they had happened. 2 sets of the results were done on the same day and the other 2 were done on 2 other days. Each set of results had 5 readings. The range between each reading was the 10cm� dilution of water added to the sodium thiosulphate solution. This is good range, as it has not got a too bigger gap from the last reading or too minute gap that I cannot detect any changes in the time for the cross to be obscured. The calculations I used to calculate the rate of reaction was: 1/time for the cross to be obscured. The 4 sets of results are on the next page. After having compared the results, I realised that the 2 sets of results done on the same day had quicker times for the cross to be obscured, which has also made the reaction faster. I repeated the other 2 results again but the times were very similar to the original results. I think the 2 sets of results produced on the same day had warmer water, which gave the particles of the solution more energy, this made them move faster and collide more frequently and more effectively to give a faster rate of reaction. I noticed that the other two experiments that were done on two other days had used colder water. So, this was probably what had caused the time difference between the results. I am going to use the 2 sets of results that were done on the same day to draw my conclusion, find averages and plot graphs because they are more reliable. - They were done on the same day, and the water and room used was roughly the same temperature. All these factors make the results of these 2 particular sets of results reliable and trustworthy. ...read more.

Conclusion

From these results I will average them to get a single reliable reading. I will also work out the rate of reaction (1/time). I will then plot 2 graphs showing the rate of reactions and how it affects the time taken to collect the gas and how the concentration of hydrochloric acid affects the time taken to collect the gas. From the graph and results I should be able to draw conclusions and see whether if my prediction is correct. Even though my method of finding how the concentration of sodium thiosulphate affects the reaction rate is good, I have researched another method which can be used for the same experiment but produces more accurate results. It involves a computer with special light sensitive equipment. It records how much light passes through the solution as the Sulphur makes it more and more cloudy. This method also involves machinery that put the reactants together for you. When you choose to do an experiment, the acid is added to the flask containing the sodium thiosulphate solution (the flask is partly covered to stop any stray light affecting the measurements). After a short time, the reaction starts and you will see the light intensity reading on the computer screen change as the Sulphur is formed. The lower the reading, the less light is being allowed through, the more Sulphur is being formed. I also had a problem when I plotted my graph. I found it quite difficult to join the points with a line of best fit. If I have to plot a graph in future I am going to use a computer as the curves will be smoother and therefore the line of best fit will be more accurate. All in all I think this was a good experiment but it could have been improved if I used more of the resources available and had more time to do the experiments. The results supported my predictions and they seem to be fairly reliable results. Sheena Lam 10H ...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. Marked by a teacher

    Chemistry Coursework - How the concentration effects the rate of reaction between sodium thiosulphate ...

    A conical flask will be used to place the solutions into and then commence the experiment. Under the conical flask will be a piece of card with a large X on it. I will then fill the 100cm� beaker with the hydrochloric acid so that I have sufficient amounts of

  2. Free essay

    Investigating the Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid

    Another important factor to ensure a fair test is to keep the colour and size of the cross the same at all times as if this is not followed, the results could be different and the test would not be fair.

  1. Experiment to Investigate the Rate of Reaction between Hydrochloric Acid and Sodium Thiosulphate, with ...

    As it is a strong acid and has is able to kill bacteria, it is used in detergents such as toilet cleaners and rust removers in high concentrations that are lethal to humans. It is very corrosive, and can cause blindness and injury to the skin if the person handling it is unprotected.

  2. Measuring the reaction rate of sodium thiosulphate in hydrochloric acid

    The chemical reaction between sodium thiosulfate and hydrochloric acid is mildly exothermic. Figure 3: 2.4 Factors Increasing the concentration of the reactants and raising the temperature bring about more collisions and therefore more successful collisions, increasing the rate of reaction.

  1. The aim of this coursework is to investigate the rate of reaction between sodium ...

    0.125M, 0.150M), the rate of reaction was fairly high. * In general, when the concentration of sodium thiosulphate was increased, the rate of reaction also increased. I think that the procedure that I used helped me achieve accurate and precise results.

  2. How does temperature affect the rate of reaction between sodium thiosulphate and hydrochloric acid?

    to obscure the black cross, meaning the reaction time also increase as the temperature increase. On my second reading at 30(0C) I didn't get a time. This is because I pressed the wrong button on the stop clock, causing it to reset, not giving me a reading.

  1. Investigation on the Effect of Temperature on the Rate of Reaction between Sodium Thiosulphate ...

    Once the cross becomes obscured from vision, I will stop the stopwatch, and note the time 7. Since I will re-use the conical flask, I will then carefully wash it to remove any remains of the reactants from it. Theory The reaction between sodium thiosulphate and hydrochloric acid can be

  2. Effects of Concentration of Sodium Thiosulphate in the reaction of Hydrochloric Acid and Sodium ...

    My controlled variable, what I will keep the same, will be the volume and concentration of hydrochloric acid. The temperature at which the reactions take place will be constant also. These are to remain the same so as to keep the test fair.

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