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I aim to find out at what strength of salt solution there is not a net change in mass of the plant tissue.

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Introduction

To find out at what strength of salt solution there is not a net change in mass of the plant tissue Teyfide Hassan AT1:OSMOSIS PLAN AIM:I aim to find out at what strength of salt solution there is not a net change in mass of the plant tissue. I will find out the water potential of the plant tissue by using different salt solutions. The water potential will be found when a plant cell is immersed in a solution, which has the same concentration of solute as the cell; there is no net loss or gain of water. METHOD 1 Get out all the equipment 2 Using a knife cut six equal mass of plant tissue 3Measure the mass of the tissue - ORIGINAL MASS 4 Measure out 30ml of solutions into labelled petri dishes 5 Place the plant tissue into each dish 6 Leave for at least half an hour 7 With filter paper wipe off any excess water before measuring the mass of each piece of plant tissue 8 Put results into a table EQUIPMENT Here is a list of all the equipment I shall be using: Tile Knife Petri dish Stop clock Filter paper Measuring cylinder Solutions: distilled water, 0.1,0.2,0.3,0.4,0.5 molar FAIR TEST To make this a fair test I will always use 30ml of salt solution. The potato will be cut into equal sizes. I will leave the potato chips in for half an hour and make sure they will come out at the same time. ...read more.

Middle

Because of this, water must be able to pass into and out of cells easily. This happens by osmosis through the cell membrane and the whole process is called osmo-regulation. Osmosis makes plant cells swell up if they are surrounded by weak solution and they become turgid. This is real useful for giving support to green plant tissue and for opening stomata guard cells. Animal cells don't have a cell wall and can easily burst if you put into pure water because they take in so much water by osmosis. Text Box: PATTERNS I noticed a few patterns the new mass of the potato in distilled water went up as water was taken in as the inside of the potato was a lower concentration then the distilled water so by osmosis water is taken in to even out the concentration. But the potato chips in the other concentrations all loosed mass and the stronger the concentration the loo is more. PREDICTION RIGHT OR WRONG? My prediction that the distilled water would gain weight and the 0.1 to 0.5 concentrations would lose mass and this is correct as osmosis is about evening up the concentration. The water molucles actually pass both ways through the membrane in a two-way traffic. But because there are more on one side than the other there's a steady net flow into the region with fewer water molecules i.e. into the stronger solution. This causes the salt solution region to fill up with water. ...read more.

Conclusion

2. Inaccurate measuring could have been a source of error, as the measuring cylinders may not have been read correctly. And because of excess water that may be left behind in the measuring cylinder when the solution is poured. 3. Another source of error could have been the temperature that the potatoes were exposed to. Depending on whereabouts in the room the potatoes were left could have allowed more sunlight on some pieces and not on others. 4. When measuring out the weight of the potato the scale would never really give one single measurement and so made it very difficult to read from. This could of lead to the wrong weight being read off. From looking at my graph I would have to say that there is only one real anomalous result, and that would be the point at the 1.4 mol solution. This result could of come from any of the above sources of error. The anomalous result is approximately 3-4% less then what it should be. I made this assumption using my line of best fit. The experiment did not really give a conclusion as to the exact concentration of salt solution required to equal the concentration of the potato therefore if I were to do the experiment again I would use readings that were closer together and that were between 0 and 0.2 Mol/dm?� as this was the concentration that the potato was nearest to in the experiment. Carrying out the experiment again will allow you to get a very accurate reading as to what the concentration of the potato actually is. ...read more.

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