• 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
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19

Osmotic pressure

Extracts from this document...

Introduction

A study of osmosis Trevor Gotting Sept 30 2007 Ida Bailey Introduction: Osmosis is when water diffuses from an area of high water concentration to a low water concentration. Also there are various effects of solute concentration on cells, which we will be studying. In this lab we will determine how osmosis affects pieces of potatoes. Also we will see how much the change of mass the potato will end up after sitting in the solute. Hypothesis: If the concentration of solutes outside the potato is higher than the concentration of cells in the potato, the potato piece should shrink. Also if both concentration of cells from the potato and the solute are equal, then the potato shouldn't change. Lastly if the concentration of cells in the solute is lower than that in the potato, the potato should get larger. Materials: see page 80. Procedure: see page 80. Change in mass observation Test tube # Solute concentration Initial mass (g) Final mass (g) Change in mass (g) Percent change in mass 1 0 4.53 g 5.49 g 0.96 g 21.2 % 2 0.2 4.54 g 4.79 g 0.25 g 5.5 % 3 0.4 4.56 g 4.46 g -0.1 g -2.2% 4 0.6 4.53 g 3.67 g -0.87 g -19.2% 5 0.8 4.54 g 3.41 g -1.13 g -24.9% 6 1.0 4.55 g 3.41 g -1.08 g -23.7% Calculations: Analyze: 1. From the graph information it shows that the solute concentration of sucrose in the potato pieces was around 0.38. If a potato piece was put into a solution with the sucrose concentration of 0.38 it would be isotonic. 2. Shown on graph 3. Some potato sections lost mass because there is a higher concentration of sucrose in the solution than the potato. Therefore the water in the potato is escaping and trying to equilibrate the solution through osmosis, causing the potato to shrink (hypertonic). Some potato sections got bigger because there was a higher concentration of sucrose in the potato than the solute. ...read more.

Middle

I never repeated any readings for this preliminary experiment as it was only a trail experiment for me to fully understand what I was doing, get used to all the equipment which I was going to use and finally to find out what concentrations of sucrose solution will be needed for my main experiment. Results: Concentration of solution (M) Original Length (cm) Original Mass (g) 1.00 5.2 4.13 0.75 5.1 4.26 0.50 4.9 4.09 0.25 4.7 3.81 0.00 4.9 4.00 After 30 minutes: Concentration of sucrose (M) Length (cm) Change in length (%) Mass (g) Change in mass (%) 1.00 4.9 -5.8 3.90 -5.6 0.75 5.0 -1.96 4.10 -3.8 0.50 4.9 0 4.06 -0.7 0.25 4.7 0 3.94 +3.4 0.00 4.9 0 4.20 +5.0 After 60 minutes: Concentration of sucrose (M) Length (cm) Change in length (%) Mass (g) Change in mass (%) 1.00 4.9 0 3.73 -4.4 0.75 4.9 -2.0 3.98 -3.9 0.50 4.8 -2.04 3.98 -2.0 0.25 4.7 0 4.03 +2.3 0.00 5.0 +2.04 4.32 +2.9 After 90 minutes: Concentration of sucrose (M) Length (cm) Change in length (%) Mass (g) Change in mass (%) 1.00 4.7 -4.08 3.59 -3.8 0.75 4.9 0 3.86 -3.0 0.50 4.8 0 3.94 -1.0 0.25 4.7 0 4.10 +1.7 0.00 5.1 +2.0 4.39 +1.6 After 120 minutes: Concentration of sucrose (M) Length (cm) Change in length (%) Mass (g) Change in mass (%) 1.00 4.5 -4.2 3.47 -3.3 0.75 4.9 0 3.79 -1.8 0.50 4.8 0 3.91 -0.8 0.25 4.9 +4.08 4.81 +2 0.00 5.2 +2.04 4.41 +1.4 Overall change in length and mass: Concentration of sucrose (M) % change in length % change in mass 1.00 -13.4 -16 0.75 -3.92 -11 0.50 -2.04 -4.4 0.25 -4.08 +9.7 0.00 +6.12 +10.2 o Therefore I decided that I would use concentration of sucrose solution for my detailed experiment to be: 0.25M, 0.29M, 0.33M, 0.35M, 0.38M and 0.40M o For my detailed experiment I decided to replicate the experiment, so I could ensure that my results are reliable and to eliminate any errors which I could have possibly made. ...read more.

Conclusion

More strikes result to more molecules passing through the pores, which in turn results in net diffusion of water from the compartment with high concentration of water to that with low concentration of water. In osmosis, water flows in a response to differences in molarity across a membrane. The size of the solute particles does not influence osmosis. Equilibrium is reached once sufficient water has moved to equalize the solute concentration on both sides of the membrane, and at that point, net flow of water ceases. Here is a simple example to illustrate these principles: Aim To find out how the concentration of the sugar solutions affects the amount of water intake by potatoes. Equipment Beakers Measuring Cylinders 6 sugar solutions of different concentrations ranging from 0.0-0.5% Weighing machine to 2 decimal places Hypothesis Potatoes are plants and they have a general plant structure. It contains a plasma membrane which will is selectively permeable, allowing water and some solutes though except larger solutes and ions. I predict that the potato piece with the lowest concentration will take in the most water through osmosis. This is because the solution is dilute and there is less water in the potato and therefore there will be a net water movement from the solution to the potato. As the solution is dilute the water potential is at its highest. I also predict that the potato with the highest concentrated solution will absorb the least amount of water as there is a smaller net movement from the solution to the potato. This is because the solution contains less water and more sugar and therefore there will be less water movement from the solution to the potato resulting in the potato piece with the lowest mass. This is because there is a low water potential. Results 2 pieces 10ml solution used Concentration of solution Weight of potatoes before Weight of potatoes after 24hr Change in Mass (%) 0.0 0.8g/0.8g 2g/2g 250 250 0.1 0.8g/0.8g 2g/2g 250 250 0.2 0.8g/0.8g 1g/2g 125 250 0.3 0.8g/0.8g 2g/2g 250 250 0.4 0.8g/0.8g 2g/1g 250 125 0.5 0.8g/0.8g 1g/1g 125 125 ...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 Life Processes & Cells 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 Life Processes & Cells essays

  1. Marked by a teacher

    Osmosis in Potatoes Lab. At which concentration of sucrose in water (% mass ...

    5 star(s)

    o At 48 Hours: 1.459g- 1.506= -0.047 g 10% Mass by Sucrose in Solution o At .5 Hours: 1.566g- 1.538= 0.028 o At 24 Hours: 1.664g- 1.538= 0.106g o At 48 Hours: 1.602g- 1.538= 0.064g 20% Mass by Sucrose in Solution o At .5 Hours: 1.618g- 1.588= 0.03g o At

  2. Marked by a teacher

    Biology Coursework - Osmosis

    5 star(s)

    Blot each potato chip with a paper towel to remove any remaining surface water before weighing the chips on some scales and noting down the results. 7. Repeat the tests two more times then use the results to draw graphs and conclusions.

  1. Marked by a teacher

    Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.

    5 star(s)

    I shall use two 100ml beakers. Approximate volumes of sucrose concentration will be poured into one of these and transferred into the measuring cylinder. This is because one is likely to make fewer mistakes using this method rather than pouring the sucrose directly from a large, heavy container where it

  2. Marked by a teacher

    Osmosis in Potato Chips

    5 star(s)

    Set up twenty one test tubes; 3 with 20cm(3) of distilled water, 3 with 16cm(3) of distilled water and 4cm(3) of sucrose solution, 3 with 12cm(3) of distilled water and 8cm(3) of sucrose solution, 3 with 10cm(3) of each, 3 with 8cm(3) of distilled water and 12cm(3) of sucrose solution, 3 with 4cm(3)

  1. Marked by a teacher

    An experiment to show osmosis in potato chips in different concentrations of sucrose solution ...

    3 star(s)

    Preliminary Experiment Aim: To have a practice run of the actual experiment and make alterations and improvements to the method designed, so that when the final experiment is held, there would be less criticisms and more reliable results. Apparatus list: * Beakers (3)

  2. Aim To determine the water potential of a potato tuber cell

    This could be achieved by using a machine to prepare the potato samples, however a machine as such was not available when carrying out my investigation. Another less significant limitation during the preparation of the samples was the fact that the sample could have unintentionally been placed on a drop of water or a wet paper towel, while weighing it.

  1. Does the concentration of sugar levels affect osmosis in potato plants?

    of the water escaped out from the stomatal pore into a higher concentration (in the potato slices) into a region of lower concentration the potato uses turgor pressure and pushes the water out into the solution this is why there is a significant decrease in mass.

  2. To investigate the effect of different concentration of sucrose on osmosis in potato chips

    measure and cut into lengths of 5cm long with scalpel. 6. Weigh each chip and measure each ones lengths after they are cut to double check if the length is accurate as possible and to check for mistakes. Note down the weights for each potato chip in a column, and also remember to write what concentration it is in.

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