• 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

To investigate how particle size affects reaction rates

Extracts from this document...

Introduction

Chemistry Coursework Purpose : To investigate how particle size affects reaction rates Key factors > Temperature > Particle size > Concentration > Measurements > Pressure > Catalysts Background information A chemical reaction involves one or more substances (reactants) that react to produce other substances (products). Chemical engineers exploit chemical reactions to produce materials on a commercial scale. Different reactions happen at different speeds (rates.) Some reactions like explosives are so fast they are almost instantaneous. For example, when a burning splint is put into a mixture of hydrogen and chlorine, there is a loud bang and hydrogen is produced: H2 (g) + CL2 (g) ? 2HCL (g) Other reactions, like the rusting of steel and the weathering of limestone on buildings happens so slowly that it may be years or even centuries before we notice their effects. The following is the way to work out the reaction rate: Reaction rate = Change in amount (or concentration) of a substance Time taken E.g. 0.1g of magnesium added to dilute hydrochloric acid disappears in 10 seconds Rate = 0.1 10 = 0.01g/s "The speed of a reaction is inversely proportional to the time taken for the reaction to finish" The rate of reactions can be measured in two different ways: > Measuring change in mass on scales > Measuring gas produced with a gas cylinder Both are equally good measures of the rate of reaction. To measure change in mass is relatively easy; you just add the reactants together and measure the change in mass. ...read more.

Middle

For the same mass, small chips can have a several times larger surface area. This therefore speeds up the rate of reaction as the reactive substance (hydro choleric acid) can be dissolving many different sides of the chips at any one time rather than having to dissolve a whole side before reaching the next bit. The diagram below shows the acid (arrows) and the chips (square) the whole one has been divided up in to segments to illustrate the area that is left unexposed as compared to the small chips. "Reactions in which the reactant is solid take place faster when the solid is divided into small pieces. The smaller particle have a large surface area to mass ratio against the larger particles" --------------- A reaction into the effects of heat on a reaction (Sodium thio sulphate and hydrochloric acid) Sodium thio sulphate and hydrochloric acid were reacted together at temperature intervals of 10?C. They produced sulphur. Warming the solution makes the sulphur form faster. There is a steep increase in the speed of the reaction as the temperature is increased. The reaction goes approximately twice as fast at 30?C as it does at 20?C. It double speed again between 30?C and 40?C and so on. The reason: At higher temperature the ions have more kinetic energy. Moving through the solution more rapidly, they collide more often and so there is a greater chance they will react each second. Therefore the reaction will finish much quicker. Safety To ensure safety, I must follow several rules when conducting my experiment. ...read more.

Conclusion

Explaination Evaluation The experiment was very successful and I would say that there do not seem to be any major inaccuracies. The result for 15 marble chips is slightly lower than anticipated but still reasonable. The results are accurate as we repeated the experiment three times and then took an average. Certainty & Experimental Error As with any experiment that is not done in a completely scientific laboratory with perfect equipment, there will be small inaccuracies that, although you may try to avoid will still be there. The actual markings on the gas syringe that we took the measurements fast cannot be 100% accurate, also we may have read the syringe slightly wrong, resulting in small inaccuracies that could affect the results. The syringe may, itself not be air tight, resulting in small amounts of gas leaking. The bung that connected the gas syringe to the conical flask may have leaked slightly, or some gas may have escaped immediately after we put the marble chips in. We did try to use all the same acid, however some may have been slightly stronger, as we did not measure the strength of each acid we used. Extension We could extend the experiment in several ways; in fact you could carry on extending it almost indefinitely. It would be a sensible start to decrease the amount of time that the samples are taken at. For example take readings every 5 seconds instead of every 10, which would give us a better picture of how the initial rate actually occurs. We could investigate how other reactants occur with marble chips and compare this to our experiment. 1 Reaction Rates Page Steve Green ...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. To investigate the factors which affect the rate of reaction between marble chips and ...

    This is because of the average result of the medium chips was 0.93 cm3 and rate of reaction for small chips is 1.30 cm3. This result has proved that the more surface area the faster the reaction. Furthermore the powdered chips would be expected to slightly higher then the small

  2. Sodium thio sulphate and hydrochloric acid reactions.

    Then I had more results to draw a conclusion on however the anomalous results I repeated several times. In this experiment there is a good chance of making a mistake therefore I need to repeat to check my results and confirm them.

  1. How higher or lower concentration and temperature affects rates of reactions

    Hypothesis; We assume that, by increasing the concentration of the substance, increases the rate of reaction because the higher the concentration is of the reactant, there is a greater chance of collisions to occur. In some cases, increasing the concentration of one of the reactants may have slight effect on

  2. Investigating Rates of Reactions

    When the temperature is increased, the number of particles with energy equal to or greater than the activation energy increases dramatically. Therefore there is a dramatic increase in the number of successful collisions and hence an increase in rate. This is the most important factor when considering the effect of temperature on rate.

  1. Free essay

    Close Your Eyes

    I shut the door and ran down the steps before she had a chance to stop me. I looked around and realised I actually had no idea where I was going and after 15 minutes of walking round in circles I eventually stopped to ask someone.

  2. Investigation to find out how particle size affects the reaction rate.

    o Hydrochloric acid - Used to displace the different particle sizes of calcium carbonate. o Calcium carbonate - Used to react with the hydrochloric acid to see whether particle size affects the rate of reaction. o Weighing scales - Used to check that the mass of the calcium carbonate remains constant so that it is a fair test.

  1. How the Concentration of a Solution Affects Rates of Reaction.

    [Source: Chemistry For You - Lawrie Ryan] Temperature: Temperature can have a large affect on rates of reaction. As the temperature raises, reaction rates increase, and as it drops, the rates decrease. This can partly be explained again by collision theory.

  2. Understand factors that affect the rates of chemical reactions - temperature, concentration of reacting ...

    Other vinegar/chalk/peroxide mixtures can be poured down the sink. Kits should be returned to SC 5414 as soon as you return to campus from the school. MATERIALS 8 test tube racks 9 aluminum pie pan 8 pairs of scissors 8 small ziploc bags 8 slivers of potatoes (not supplied)

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