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

An experiment to show the relationship between shape and diffusion rate

Extracts from this document...


An experiment to show the relationship between shape and diffusion rate Aim To see whether there is a relationship between the surface area and the diffusion rate Hypothesis I predict that the smaller blocks of agar will turn clear, or diffuse first, as it has a smaller surface area. This is because there is less surface area and volume for the sulphuric acid to diffuse into. Apparatus * Three sizes of agar, 20x20x20mm, 20x20x10mm, 20x20x5mm * 240ml of sulphuric acid [80ml per beaker] * 3 100ml beakers * Tile used for placing the agar * Tissue to wipe off the sulphuric acid off the agar * 3 scalpels * Ruler, measurable in mm * Stop clock * Calculator Method 1. First, cut three pieces of sulphuric acid in the following sizes 20x20x20mm, 20x20x10mm, 20x20x5mm, as accurately as possible 2. Next, fill the three beakers with 80ml of sulphuric acid each 3. Then, prepare the stop clock, and make sure it is has been reset 4. ...read more.


Surface area/mm� 2400 1600 1200 Volume/mm� 8000 4000 2000 Surface are to volume ratio O:O.3 O:O.4 O:O.6 Conclusion My prediction as to which block will go clear first was correct, being the smaller block, as its surface area to volume ratio was the greatest out of all three, even though there was not much difference between the three values. This is because the third block has a greater surface area for the sulphuric acid to diffuse into the agar, causing the diffusion rate to be greater. The blocks have become 'clear' through diffusion caused by neutralization between the sulphuric acid and the agar, which is an alkaline. Evaluation Quite a few things did not go as planned in this evaluation, but I have come up with ideas on how to improve them if we do an experiment like this again. Firstly, the jelly size may not be accurate from cutting it, and when it has been stirred, bits of it may have chipped off causing a change in its surface area. ...read more.


This problem may be reduced by measuring the sulphuric more carefully, maybe with a measuring cylinder before then placing it into the beaker, instead of measuring it into the beaker straight away. Our measurements of the depth of the clear layer of the blocks of agar jelly may have been incorrect as well, and to prevent this, we could possibly use a microscope next time and use a graticule to measure the depth that the jelly has diffused to obtain a more accurate result. The last problem I noticed while doing the experiment was when we were blotting the sulphuric acid off the agar. I found that there may have been some sulphuric acid left on the agar after we have blotted it, which may have caused further diffusion and adjusting our result. This is caused from not blotting off enough sulphuric acid off the agar. Next time, we could carefully blot all the sulphuric acid, and use one piece of tissue for each block of agar so that there is no sulphuric acid on the tissue before blotting each block of agar. ?? ?? ?? ?? Macha Cauchois ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Physical Chemistry 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 AS and A Level Physical Chemistry essays

  1. Heat of Neutralization

    Experiment No. 1 2 3 4 5 Vol. of ~1.0M alkali(aq) 25.00 20.00 15.00 10.00 5.00 Vol. of 1.0M acid(aq) 5.00 10.00 15.00 20.00 25.00 4. The content in the polystyrene foam cup was let equilibrate for a few minutes and measured the temperature of the solution (initial temperature).

  2. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    Page 37 shows the graph (graph 3.5.3) of against concentration for hydrogen ions. It is clear from the graph that the correlation is not linear, so the reaction is not first order with respect to hydrogen ions. I suspect that the reaction is second order with respect to hydrogen ions.

  1. The Determination of rate equation

    Concentrated solutions of this acid are extremely corrosive; very dilute solutions are mildly corrosive. Toxic by inhalation - the concentrated solution releases dangerous quantities of hydrogen chloride vapour. If it does come in contact with your skin then rinse with cold water immediately and if it comes in contact with

  2. detremining the rate equation

    * 100 cm3 conical flask this where the reaction takes place ( where the reactants will be mixed) * a black cross drawn on a white tile- this will be used to determine the end of the reaction when it disappears.

  1. Investigating how concentration affects rate of reaction

    I came across a few problems that need to be adjusted in my final experiment. I originally decided to just monitor the temperature of the water bath, but soon realised that this would most likely not share the same value as the solutions in the boiling tubes.

  2. To investigate the relationship between the time taken for diffusion and cell dimension.

    That is why we see that the surface area to volume ratio decreases as size increases. As the gelatin block grows it needs to carry out more and more reactions with the hydrochloric acid in order to turn fully pink.

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