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Chemistry Rates Reaction Coursework

Doc Brown's Chemistry KS4 science GCSE/IGCSE Revision Notes

A BRAINSTORM on "Rates of Reaction" for chemistry coursework investigations-projects

Ideas for coursework assignments or projects involving the rates or speed of chemical reactions and is a companion page to see also the DETAILED GCSE Revision Notes on the Factors Affecting the Rates of Chemicals which also has brief descriptions of experimental methods and equations, particle pictures and fully explains all the factors affecting the rate of a chemical reaction

Advanced level chemistry theory pages for GCE/AS/A2/IB and adventurous GCSE students!

and A few health and safety ideas on risk assessment

AIM for a high investigation-project mark - you have nothing to lose for your assessment!

 e.g. suppose you are investigating the effect of hydrochloric acid concentration on the rate at which the acid dissolves limestone (calcium carbonate)
  • BUT you can use and extend these 'brain stormed' ideas to most rates of reaction coursework assignments
e.g.
  • The magnesium/zinc + acid reaction, you can investigate acid concentration and amount of metal
and the zinc reaction is catalysed by copper and other ions in the acid).
  • Decomposing hydrogen peroxide with a solid catalyst or soluble transition metal compound.
  • Enzyme catalysed reactions e.g. decomposition of hydrogen peroxide solution by catalase
  • (can tricky at GCSE level).
  • The sodium thiosulphate-hydrochloric acid reaction, you can investigate the effects of temperature and concentration.
  • (as far as I know sulphur formation is only catalysed acid)
  • and these reactions get a mention here and there and don't forget to pre-study the rates of reaction revision notes, lots of theory and descriptions of experimental methods and graphs etc.
  • WARNING
    : Your write-up must be your work produced from your study and your experiments.
    • This web page is meant to teach you how to tackle an coursework e.g. on rates, it is not meant to be copied and the details filled in! Your coursework write-up must expressed in your language and expressed at 'your scientific level'.
    • Your teacher will have a good idea what to expect and you must be able to justify all your write-up. Use the sources/references mentioned below and clearly indicate them in your write-up.
    • More marks are lost by not writing things down, than by not doing experiments! Your write-up must be your work produced from your study and your experiments. This web page is meant to teach you how to tackle an coursework e.g. on rates, it is not meant to be copied and the details filled in!
    • Your coursework write-up must expressed in your language and expressed at 'your scientific level'. Your teacher will have a good idea what to expect and you must be able to justify all your write-up.
    • Use the sources/references mentioned below and clearly indicate them in your write-up. More marks are lost by not writing things down, than by not doing experiments!
    • EMAIL a query or comment on the rates/coursework ideas pagesbut I do NOT do students coursework for them, neither do I replace your teacher supervisor! however I sometimes get really interesting questions and learn something new myself - and that's always a pleasure!

      A BRAINSTORM outline of a whole investigation is outlined below, it is not meant to be prescriptive, but can form the basis of aiming for a high mark and hopefully give you plenty of ideas.
    • For sources and references you should research 'rates of reaction' for theory, experimental methods etc. using textbooks, the Internet, and of course your class work and exercise books and mention your research sources in your coursework report AND QUOTE YOUR RESEARCH SOURCES  and ANY PREVIOUS 'RATES' EXPERIENCES
    • Any previous 'rates of reaction' experience is invaluable and can be used/quoted in your write-up - particularly knowledge of experimental methods which can count as preliminary work.
    • Word process your work if you can and your results can be tabulated and processed into graphs using software packages like Excel
    • Preliminary work usually involves doing a few trial runs of the experiment to see how it goes and making modifications if necessary. By writing up how, and why, you have changed the experimental conditions or 'recipes' you can gain more marks.

    skill P: Planning - the theory and your experiment design!

    First, you can start by describing the reaction situation you are intending to  investigate e.g. with the word and symbol equation, short description about the reaction, and this sets the scene.
  • If you are confident and chosen the VARIABLE you want to investigate you should try to make a prediction and maybe justify it with some theory if you can.
  • You can continue in a broader context by introducing some background theory and descriptions of the factors or VARIABLES which may have an effect on the rate of the reaction you are studying (include briefly factors which might not apply). In your 'method' description use the correct units or descriptors.
  • The factors to discuss might be ...  amount of limestone?, temperature of reactants?, acid concentration?, volume of acid?, size of limestone pieces? (relate to surface area?), stirring of the reacting mixture, size of reaction vessel, volume of thiosulphate, any added water to dilute etc.
  • Is there any other factor for the reaction you are studying?, will any of the reactants or products be affected by change in temperature or pressure? e.g. there are several reasons why the same acid should be used if its a reactant in the investigation, e.g. (1) its the hydrogen ion, H+(aq), is the active ingredient that actually 'attacks' the metal or carbonate, and acids can ionise to different extents, (2) 1 molar or 1 mol dm-3 (1M) H2SO4 is twice as acid as 1M HCl because each H2SO4 provides 2 H+'s whereas each HCl just 1.
  • If you have decided, for example, to investigate the effect of acid concentration on the speed of a reaction, then everything else should be kept constant for a fair test, and this should be obvious in your plan for the reasons discussed above!
  • If you haven't already chosen the VARIABLE, do so now, and make a prediction and justify it with some theory which you may have previously described and should refer to.
  • Next you should describe initially, but briefly, some methods for following the reaction = measuring the speed of the reaction. If a gas is formed, there are at least two ways of collecting a gas e.g. initially empty gas syringe or a measuring cylinder/burette full of water inverted over water with appropriate tube connections and there is one other very different method available for 'following' the reaction using a balance to record the mass loss.
  • The hydrochloric acid - sodium thiosulphate reaction depends on the time for a certain amount of sulphur precipitate to form and obscuring a marked black X on white paper.
  • Briefly
  • explain how the method can be used to measure the speed - the results of the first few minutes is usually the most crucial - you can discuss (briefly) other methods, but perhaps better in evaluation as a means of further evidence.
  • When you have decided on the method, give a detailed description of how you might carry it out. Include details of the amounts of chemicals you might use mass, volumes, dilutions + UNITS etc. etc.
  • Clearly indicate why the method would be expected to produce precise and reliable evidence - the results!
  • Include 'health and safety' points.
  • If you are looking at changing the reaction temperature, its not easy to accurately vary and control the temperature of the reactants without a thermostated water bath to hold the reaction flask in. Even with a thermostated water bath (normally only available to advanced level students), all the reactant solutions should be pre-warmed in the bath before mixing and start the timing and recoding of results. 
    • If you are varying temperature, you need to heat up the reactant solutions separately and take their temperatures, mix, start stopwatch. However, they will cool a little standing out in the laboratory, so not completely satisfactory solution to the problem. In the case of the sodium thiosulphate - acid reaction, you can leave the thermometer in the flask and take the temperature at the end, then use an average for the temperature of the reaction.
    • If temperature isn't a variable, it must be kept constant. The simplest solution here, is to make sure all the chemicals have been standing in the laboratory prior to the lesson. Then, they will all be at the same temperature, which should be recorded. If more experiments are conducted at another the time, the temperature must again be checked and recorded.
  • Refer to any previous laboratory experience with 'rate of reaction' experiments which may have helped you decide and design the experimental method.
  • A clearly labelled diagram of the method with a brief outline of how you intend to carry out the experiments - this  cuts down on the writing and makes the scene clear!
  • You must give details of  how long you might time the experiment as well as the time interval between experimental readings
  • REMEMBER you can change your 'recipe' or way of doing the experiment. If you have to change anything, describe and explain the changes you have made to the procedure (some of this might count as valuable marks for the EVALUATION skill)
  •   AND DON'T FORGET AT ALL TIMES QUOTE THE CORRECT UNITS in P, O, A or E.

  • skill O: Obtaining evidence - observations, measurements, in other words the results! (possibly some data you might have been given)

    These must be clearly recorded in neat tables showing all the units e.g.

    Run 3: acid concentration ?????, temperature ????
    Time ????Gas volume ????Gas volume ??? (repeat)corrected gas volume ???
    0?????????
    153???
    2119???
      You can produce a summary table with the average/corrected (if necessary)  gas volumes v time for all the different acid concentrations or whatever variable
      • For the hydrochloric acid - sodium thiosulphate reaction you are recording just the reaction time for different thiosulphate or acid concentrations or temperatures, so the data gathering and subsequent processing is 'simpler'.
    • All experiments should be repeated where time allows to check for accuracy and consistency, this may become more necessary after you have done a preliminary analysis
    • The 'bung effect'! - look up about dead volumes and its correction when dealing with gas volumes!
    • Your recorded results should indicate the accuracy of the measuring equipment e.g. 0- 2 decimal places.
    • Some of the work done here in presenting the results, e.g. working out averages etc. actually counts towards the mark for analysing (described below).
    • Have you got enough results, do they seem ok? Starting the analysis as soon as possible will help you decide whether further, wider ranging or repeat  experiments  - best decided after examining the graphs of results (see below) - difficult to decide just looking at tables of data.

    skill A: Analysing and considering the evidence - what do the results mean in terms of your prediction and theory!

    The results are initially processed into graphical form ('graphing') for several reasons for both the analysis and evaluating the experimental  .... they can clearly show the general trend of the effect of changing that factor or variable, highlighting experimental 'runs' that don't seem to fit the pattern of the other sets of results for the other runs, individual points that don't seem the pattern of a particular sets of results - BUT ITS UP TO YOU
  • Ideally you should plot the average(*) corrected gas volumes on the y axis and time on the x axis - what should the origin be? (* May depend on the consistency of your results).
    • For the hydrochloric acid - sodium thiosulphate reaction you can plot either (i) reaction time, or (ii) 1/time versus a concentration or temperature (1/time = relative rate of reaction).
  • It is best, if possible,  to have all the average results points plotted on the same graph for easy comparison - take care because this may involve 4 or 5 lines for 4 or 5 different acid concentrations
  • Make sure you use a clear KEY for the different line points and a clear title for the graph AND clearly label the axis including the units  or whatever ..
  • Use smooth 'best curves' for as many of the points as possible, though some parts of the graph might be linear, watch out for the 'scatter' - the experiment is not that easy to get good results.
  • From the graph you can then describe in words what the results mean, always refer to the graph lines and gradients directly - don't make vague comments.
  • So what we are after is the main 'trend(s)' or 'pattern(s)' describing with reference to the graphs.
  • Does the 'trend' of all the graph lines support you're your prediction, are all the results consistent with your prediction AND theory?
  • For different the acid concentrations you can do a 2nd and more advanced graphical analysis of the limestone results. This involves measuring from the graph, the speed of the reaction at the start. Explain why best data at the start? (i.e. first 3-5 mins?).
  • What graph could you then plot?...   where does the graph line start?, origin?, what is the 'shape' of the graph? is it a better way of showing consistency (or inconsistency!) in your results?
    • We are basically talking about plotting the initial rate versus e.g. acid concentration.
    • If you are doing something like the hydrochloric acid - sodium thiosulphate reaction, your reaction time measures the formation of a fixed amount of sulphur per 'time'. So the rate is 'x amount of sulphur per time', which means the speed or rate is proportional to 1/time, then plot this 1/time against the concentration of the acid.
  • From this graph re-discuss your findings in a more mathematical way and relate this to the particle collision theory of reactions! It's all about chance!  and explain why/why not the results support your prediction.

  • skill E: Evaluating - and how good are your results then? error sources? can we improve the existing method? are there other experimental methods?

    Do your results seem consistent and accurate - always refer directly to the graph or graphs in your analysis ... do any of the sets of results not fit in with the others?, do most/all sets of results fit a pattern?, are there any particular points that don't fit the pattern? (anomalies), can some results be ignored in drawing your conclusion(s)? if so, which results and why? QUOTE DIRECTLY - WITH REFERENCE TO YOUR GRAPH(s)
  • Discuss possible sources of error which might lead to inconsistent results i.e. points or sets of results that don't fit the pattern AND how could the method be improved to minimise these sources of error ... e.g. chip size? ,temperature or pressure checks for each experiment? dead volume?, ? gas syringe operation? draughts? where these or any other factor OK? in other words how suitable was the method overall? Do think the results are reliable bearing in mind any anomalies?
    • For the hydrochloric acid - sodium thiosulphate reaction think about the precipitate, observing it etc.
  • What further experiments, using the same method or another method, could be done to support your prediction or conclusion? In other words give some detailed ideas on further work that would provide additional relevant evidence.
    • e.g. in the case of the sodium thiosulphate - hydrochloric acid experiment , you can use a light gate to detect the precipitate formation. The system consists of a light beam emitter and sensor connected to computer and the reaction vessel is placed between the emitter and sensor. The light reading falls as the sulphur precipitate forms.
  • Keeping the temperature constant is really important for a 'fair test' if you are investigating speed of reaction/rate of reaction factors such as concentration of a soluble reactant or the particle size/surface area of a solid reactant. On the advanced gas calculations page, temperature sources of error and their correction are discussed in calculation example Q4b.3, although the calculation is above GCSE level, the ideas on sources of errors are legitimate for GCSE level.
    • Note that if the temperature of a rates experiment was too low compared to all the other experiments, the 'double error' would occur again, but this time the measured gas volume and the calculated speed/rate of reaction would be lower than expected.
  • -
  • This page should help with rates of reaction coursework projects or assignments investigations


    Rate of Reaction

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    Rate of Reaction Coursework

    Aim: To investigate how temperature affects rate of reaction.

    Introduction: I am going to investigate how temperature affects the
    rate of reaction of hydrochloric acid with calcium carbonate.

    This is the reaction that will take place:

    Hydrochloric acid + Calcium Carbonate è Calcium Carbonate + Water +
    Carbon Dioxide

    The rate of reaction can be measured in various different ways:

    * Using a balance you can check the mass before the reaction and
    then after the reaction has taken place. Then check the change in
    mass.

    * You can also use the method of obscuring a cross with sodium
    thiosulphate and time which cross becomes invisible first.

    I am going to use a syringe to measure the amount of carbon dioxide
    given of at regular intervals. This is because it is accurate as the
    smallest division on it is 1ml.

    The important variables are:

    * Temperature – if it is increased the reaction as the particles
    will have more energy.

    * Number of calcium carbonate chips – if there are a lot of chips
    more carbon dioxide will be formed.

    * Amount of acid – if there is more acid the rate of reaction will
    be faster.

    * Surface area – if the chips have a larger surface area then the
    rate of reaction will be faster.

    Prediction:

    I have chosen to investigate the affect of hydrochloric acid on
    calcium carbonate chips. I predict that as the temperature of the acid
    increases so will the rate of reaction. This is because for two
    substances to react they have to have a successful collision which
    means the have to collide with a minimum amount of energy which is
    called the activation energy.

    This diagram shows how the particles will react with each other with
    the minimum amount of energy (activation energy):

    The higher the temperature of the acid the faster the acid particles
    will be moving around as they’ll have more energy and there will more
    collisions. This energy will also allow there to be more successful
    collisions and so more carbon dioxide will be formed in smaller amount
    of time. Therefore the rate of reaction will be faster.

    This diagram shows the reaction of particles with more energy from the
    heat:

    I can also predict that the shape of my final graph of rate of
    reaction and temperature will look like this:

    From this graph I can predict that as I increase the temperature by
    10°C the rate of reaction will double.

    Apparatus: 1 Bunsen burner

    Calcium Carbonate chips

    Hydrochloric acid

    1 Syringe
    1 50ml measuring cylinder
    1Heatproof mat
    1 Wire gauze
    1 Conical flask
    1 Beaker filled with ice
    1 Thermometer
    1 Clamp

    I chose to use the syringe as it has small divisions to help me make

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    Related Searches

    Rate Of Reaction         Carbonate Chips         Activation Energy         Carbon Dioxide         Calcium Carbonate         Collisions         Syringe         Diagram        




    an accurate measurement of the amount of carbon dioxide formed. I
    chose to use a 50ml measuring cylinder rather than a 100ml one because
    it has smaller divisions on it and is therefore more accurate.

    Method:

    1) Set up syringe as shown in the diagram.

    2) Measure 50ml of hydrochloric acid, at room temperature, using the
    measuring cylinder and pour into conical flask.

    3) Immediately put 5 calcium carbonate chips in the acid and seal the
    top using the cork on the syringe.

    4) Start the stopwatch straight away and record the volume of carbon
    dioxide formed every 10 seconds.

    5) Repeat the experiment to ensure the results are reliable.

    6) Repeat steps 1 – 4 for a range of different temperatures. Use the
    beaker filled with ice to cool the acid and the Bunsen burner to warm
    it.

    Fair test:

    To make this a fair test I will control a various variables that will
    affect the rate of reaction. I the only variable I will change is the
    temperature as this my independent variable. However I have to keep
    the all other variables constant. I will use the same number of
    calcium carbonate chips every time I repeat the experiment, if I use
    more one time and less another time then the rate of reaction will
    increase or decrease accordingly. Along with same number of chips I
    will try to ensure that the chips that I use have the same surface
    area because if the surface area changes so will the rate of reaction.
    Also I will use the same amount of acid throughout the experiment
    because if there is too much acid the rate of reaction will be fast
    but if there is too little then it will be slow. In addition to this I
    will ensure that the acid is of the same concentration throughout the
    experiment.

    Reliability: To make my results reliable I will repeat the experiment
    and find an average volume of carbon dioxide formed at each
    temperature. I will also use temperatures ranging from 15 degrees
    Celsius to 60 degrees Celsius. Also to make sure I have enough points
    on my graph to show a strong correlation I will take 6 readings of
    carbon dioxide gas formed at each temperature. When I repeat the
    experiment if I have any two points at the same temperature which are
    very different I will repeat the experiment and I will use the results
    which are closest together to find the average.

    Safety: To ensure safety I will wear goggles to protect my eyes from
    the acid. I will also wash my hands after using the acid as it is an
    irritant.

    Preliminary: From my preliminary work I learnt that if the temperature
    of the acid is too low then it doesn’t react with the calcium
    carbonate and no carbon dioxide gas is given off. I also found out
    that if the temperature is too high the calcium carbonate reacts too
    quickly and we can’t make enough readings of carbon dioxide formed.
    This is why I am using the range of temperatures from 15 – 60 degrees
    Celsius.

    I also realised if I use small chips of marble they react too quickly
    as well and as temperature increases it isn’t possible to make enough
    readings of carbon dioxide formed. This is because the smaller the
    surface area the higher the rate of reaction.

    GRAPH

    GRAPH

    I worked out the rate of reaction by choosing a point on my line or
    curve of best fit and then dividing the volume by the temperature (the
    initial gradient). I used these results to draw my graph of rate of
    reaction and time.

    Conclusion: In my graphs of temperature and volume of carbon dioxide
    formed the line of best fit shows an increase of carbon dioxide
    formed. Also if I compare the line of best fit I can see that the
    graphs with the higher temperatures have a steeper line. On the graph
    of rate of reaction and temperature the shape shows the doubling of
    the rate of reaction. From this I can conclude that as the temperature
    of the hydrochloric acid increases so does the rate of reaction.

    The reason for the rate of reaction increasing with the temperature
    is, as the acid gets hotter the energy of the acid particles
    increases, therefore causing more successful collisions. For a
    successful collision to take place the acid particles must have a
    minimum amount energy called the activation energy. With this energy
    the acid particles can collide and react with the calcium carbonate
    particles, but if the acid particles don’t have the activation energy
    even if they collide with chips a reaction won’t take place. I know
    that the activation energy for this reaction was approximately 15°c; I
    know this because if the temperature was any lower than this no carbon
    dioxide would be formed. Therefore as I increased the temperature the
    particles gained more energy and had more successful collisions with
    the calcium carbonate chips, this increased the amount of carbon
    dioxide formed.

    My graph of rate of reaction agrees with my prediction because as the
    temperature increases so does the rate of reaction and from my line of
    best fit it is possible to see that as the temperature increases by
    10°C the rate of reaction approximately doubles. For example when the
    temperature is 25°C the rate of reaction is 0.34ml/s and when the
    temperature increases to 35°C the rate of reaction doubles to
    0.68ml/s. This proves my quantitative prediction to be correct; as the
    temperature increases the rate of reaction doubles.

    Also my other graphs of amount of carbon dioxide formed and
    temperature also agree with my prediction. This is because on the
    graphs with higher temperatures the line of best fit is steeper and so
    the initial gradient is higher, this proves that as the temperature
    increases so does the rate of reaction.

    Evaluation: I think that my measurements were quite accurate but not
    completely because if they were there wouldn’t be any anomalous points
    on my graphs. I think that the syringe I used was accurate because its
    smallest division was 1ml. Also my measuring cylinder was accurate as
    it was a 50ml measuring cylinder and again it had small divisions of
    1ml, if I had used a larger measuring cylinder it wouldn’t be as
    accurate because the divisions on it would be bigger. However whilst
    making measurements I might’ve made a few human errors. Also when I
    was measuring the volume of carbon dioxide formed sometimes it was
    difficult to read the amount formed as it was in between the small
    divisions so I had decide which millilitre it was closest to, this
    might caused error as the measurement wasn’t exact. Also when I
    measured the acid I tried to use the lower meniscus but in some cases
    I forgot to check and so some measurements might not have been
    completely accurate. Furthermore when I added I chips of calcium
    carbonate to the acid they started to react straight away but I
    couldn’t put the bung in straight away due to my slightly slow
    reaction time, this is one of the human errors that I caused.

    To get more reliable results I could’ve repeated my experiment again
    to get a more reliable average. Some of my averages weren’t reliable
    because when I repeated the experiment for the second time the first
    and second time the results were not similar.

    I might have some incorrect results because my evidence isn’t
    completely reliable. The reason for this is, I only measured the
    volume of carbon dioxide formed for 60 seconds, and to make my
    evidence more reliable could have taken more measurements so I could
    draw firmer conclusions.

    To improve my experiment I could have used a balance to measure the
    change in mass of the acid and calcium carbonate chips. This would
    have been more accurate because I wouldn’t have to worry about carbon
    dioxide escaping before I put the bung on. Another reason this method
    would be more accurate is because when I counted the chips some were
    different sizes and this made my results slightly less reliable.
    However if I could weigh the chips then I would know the exact mass of
    calcium carbonate that I started with. Therefore I could use the same
    mass of calcium carbonate every time and this would make my results
    more reliable.