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

Effect of concentration on osmosis.

Extracts from this document...

Introduction

Effect of concentration on osmosis. Aim To find out how the concentration of sucrose solution affects the mass of the potato chip left in the solution for one day. Prediction I predict that when the sucrose concentration is low the potato chip will gain mass. This is because there will be a higher sucrose concentration in the potato chip so water will go into the potato from the solution. I predict that when there is a high concentration of sucrose the potato will lose mass. This is because there is a higher concentration of sucrose solution in the solution compared to that in the potato chip so water from the potato will go into the solution to even it out. Osmosis is "the movement of a solvent through a selectively permeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane" Osmosis is the movement of water from high water concentration to lower water concentration through a selectively permeable membrane. Selectively permeable membranes are very thin layers of material (cell membranes are selectively-permeable), which allow some molecules to pass through them but prevent other molecules from passing through. Cell membranes will allow small molecules like Oxygen, water, Carbon Dioxide, Ammonia, Glucose, amino-acids, etc. to pass through. Cell membranes will not allow larger molecules like Sucrose, Starch, protein, etc. to pass through. In my experiment I will have a test tube with a potato chip in. ...read more.

Middle

Put them in the test tube rack. Then weigh the chips one at a time and record its mass and which solution it will go in so that you will be able to compare the mass before and after. Once they are weighed put them in the correctly labelled test tubes. Then measure out the sucrose for each of the tubes accurately and put it in then measure out the distilled water and put that in. Leave them in a safe place overnight and return to them the following day. Pour away the solution from each test tube and dab dry the chip with a paper tissue. Weigh each of the chips and record the results. Do the same for all the test tubes. I did one trial run before I did it for real. I did not measure the length of the chips but then I decided it would be interesting to see what the effect was on the length. I did not have any big problems in the trial run. My results were as follows: Concentration (mol) Average Mass before (g) Average Mass after (g) Difference (g) 1 2.723 2.193 -0.53 0.75 2.984 2.587 -0.397 0.5 2.34 2.161 -0.179 0.25 2.49 2.514 +0.025 0 2.62 2.789 +0.169 From this I can see that my prediction was correct but I would like to measure the length as well in the real experiment. I found that the concentration of the potato must be between 0.5 and 0.25 as that is where the graph would have crossed 0. Results Table showing mass. ...read more.

Conclusion

Evaluation I think that the experiment could have been improved to give me more accurate results. If I were to do it again I would have more results to take an average of at each level of concentration by having more chips in each test tube. This would make it more accurate as when I had two in a test tube if one of them was a long way out it made the graph not follow the line well when I plotted the averages. There was one anomalous result at 0.5 mol. I think this was because we patted them dry when we got them out of the test tubes as we did not want to weigh there water on the outside of the potato but I think that we may not have dried them all equally so this anomalous result may have been due to it having water left on the outside of it. Also the potato itself was not from the same part of the potato and was not exactly the same size, although I did try to cut them to 36mm each. I could also try the same experiment but with different volumes of cell tissues and see if the percentage change differed with a bigger and smaller surface area. I could now investigate the smaller range near to 0.25 to see the sucrose concentration equivalent to the potato. Finally, I could extend the experiment to a more exact level by looking at the potato cylinders under a microscope, then I would be able to see the cells in greater detail and draw some more observational results. Samantha Hopkinson 11lv ...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 Exchange, Transport & Reproduction 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 Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Biology coursework planning - the effect of lead chloride on the growth of cress ...

    5 star(s)

    Two methods were chosen, namely grid 1 and grid 2 (as discussed below). Since the first test portrayed that the best medium to use was cotton pads, the second test was carried out using these. The method below simply describes how the test was conducted: * Place a cotton pad into three separate petri dishes.

  2. Marked by a teacher

    The Effect Of Temperature On The Permeability Of The Cell Membrane

    3 star(s)

    If I get unreliable results then I can know that my factors that need to be kept constant were not kept constant accurately. These are the factors that need to be kept constant Surface Area Of Beetroot Mass Of Beetroot Volume Of Water Beetroot is in Time For Each Test

  1. Marked by a teacher

    Effect of temperature on membranes

    3 star(s)

    It is claimed that the beetroot aids tissue growth, lowers blood pressure, reduces risk of osteoporosis, prevents certain cancers, lowers cholesterol, is high in powerful antioxidants and is able to treat anaemia and fatigue.8 The beetroot has a spherical

  2. permeability of beetroot membranes

    We decided to measure how changing the concentration of the glucose solutions affected the rate at which osmosis takes place in potato tissue. Our controls for this experiment were the amount, size and shape of potato, the apparatus used and the volume of solution used for each concentration.

  1. An investigation into changing the concentration of sucrose soltion on the rate of osmosis ...

    the lower the solute molecules present in the solution the faster the rate of osmosis. At 0.2 M concentration the potato chips again showed a considerable increase in mass. However if we compare the chips in the 0.2 M solution to the 0 M solution there is a significant difference in mass-5.2g.

  2. Design an experiment to investigate the effect of temperature on the movement of a ...

    This means that the oxygen atom is more negative, whereas the hydrogen atom in the bond is more positive. Therefore the oxygen and hydrogen attract because they have opposite charges, causing a hydrogen bond. Hydrogen bonds are very weak, however if there are lots of them they can have a significant effect, as in the secondary structure of proteins.

  1. Osmosis in Potato cells

    Time in which each potato chip is left in the solution. Each potato chip needs to be left within the solutions for exactly the same length of time as one left in for longer will either lose or gain more in mass or length.

  2. Aim: To find out the water potential of potato cells using different concentrations of ...

    I thought all the information I have gained and used had good terminology to explain the theory of osmosis, water, pressure solute potential. Also they all provided and agreed with the same theory. Prediction My investigation is to find out the water potential of potato cells using different concentrations of sucrose solutions.

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