• 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 ...

    Vol. Water (cm�) Time (seconds) Concentration (Mol.dm ) 5 50 0 27.82 0.15 5 40 10 40.37 0.12 5 30 20 54.28 0.09 5 20 30 79.22 0.06 5 10 40 209.62 0.03 5 0 50 - 0.0 Fro my preliminary test and results, in the final run of the experiment I did not actually change anything.

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

    When handling hot beakers and measuring cylinders a pair of tongs will be used. A gauze and heatproof mat will be used while heating to avoid any damage to the equipment. During the heating stage of the experiment, a blue flame will be used throughout.

  1. The reaction between sodium thiosulphate and hydrochloric acid:Looking at the graph the order of ...

    The great majority don't have enough energy, and will simply bounce apart. Investigation 3: The effects of temperature changes and catalyst The same calculations as above were carried out to find out the activation energy (refer to figure 4.3). The activation energy for the effect of iron (lll)

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

    However, the graph agrees with the prediction to the extent of temperature affecting the rate of reaction directly, and that the increase in the rate of reaction increases with the temperature. This can be coupled with the similarity of the real line to the theoretical line, which I believe is evidence enough that this increase is exponential.

  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. Rate of Reaction between Hydrochloric Acid and Sodium Thiosulphate.

    As it is poured in, the stopwatch will be started and time taken for the cross underneath the beaker to disappear from view will be recorded. This will then be repeated for accuracy and, if the two results vary greatly, they will be repeated again.

  1. How does temperature affect the rate of reaction between Hydrochloric acid and sodium thiosulphate ...

    Anomalous Results From the results that I obtained none of the results that I collected were anomalous and they all fitted to a certain extent of accuracy into a pattern.

  2. Investigating the effect of temperature on the rate of reaction between Sodium Thiosulphate and ...

    This is based on the collision theory. Therefore my prediction was correct, as it was exactly the same as the conclusion. This shows that I managed to use my scientific knowledge to make an accurate prediction. Explanation: When gases or liquids are heated the particles gain kinetic energy and move faster.

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