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# An experiment to find out the concentration of potato cells

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Introduction

An experiment to find out the concentration of potato cells Planning The aim of our experiment is to find out the concentration of potato cells by constructing a method in which we are going to work. Apparatus: 5 beakers (200ml) Spatula Cork bearer Knife Scales Tape measure Glass rod We are going to cut up a potato into 15 pieces with a core bare, so that they are the same size, so that it'll be a fair test. We will carefully cut of the skin of the potato, as it is a few cells thick so therefore it's not a semi-permeable membrane so osmosis cannot take place, osmosis is the diffusion of water molecules through a semi-permeable membrane (see diagram below). We will then measure and weigh the 15 pieces of potato, then record them in a table. We are going to add water to equal sized beakers and then mix in different amounts of sugar to make sugar solutions of different concentrations (see table below). Then we will add 3 pieces of potato to each beaker and leave it for 24 hours. Concentration of sugar solution (M) ...read more.

Middle

In fact, the solute movement is wholly determined by fluctuations of the collisions with nearby solvent molecules. However, the average thermal velocity of the molecule is the same as if it were free in a gas phase. Whenever a solute movement is blocked by a wall it will transfer momentum to it and, therefore, generate pressure on it. Since the velocity is the same as that of a free molecule, the pressure will be the same as the pressure of an ideal gas of the same molecular concentration. Hence, the osmotic pressure p is given by van't Hoff formula: p = cRT Where c is the molar solute concentration, R is the gas constant, and T is the absolute temperature. This formula is the same as the pressure formula of an ideal gas. Diagram 2 shows connected vessels separated by a semi permeable membrane. If there is only water in the device, the level will be the same at both sides. When solute molecules are added to one side, water will start to flow into it, so that its level will go up at this side, and down at the other side. ...read more.

Conclusion

All weights before the experiment were 1.6g, the length and width of the potato pieces were all the same. All experiments were attempted 3 times and all were left for the same period of time. Evaluation of experiment We followed the plan correctly; I believe we gained accurate and sufficient enough results to conclude the experiment, and to prove our hypothesis. My final results were very reliable, due to the precautions I took to make this a fair test. Using more types of molar sucrose solutions would have helped us obtain better results, and more accurate results; so that we can make sure the results are totally correct. Experimenting with one set for a longer period of time, for each set, would lead us to better results, because the osmosis action would reach its maximum capability, and therefore tell us how much water could be transferred for each solution. Repeating the same tasks more than three times would not have affected the results as all the results were very close. Overall, given the apparatus that we got to carry out the test, I think this experiment turned out to be very successful. ...read more.

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# Related GCSE Life Processes & Cells essays

1. ## Osmosis is defined as 'the movement of water molecules from an area of high ...

The results were fine and by looking at the weights measured before the experiment, you can see that there is no reading which seems to be out of the line. As the weights before the experiment range between 4.62g and 4.87g, this tells us that the potato pieces were cut well, and I believe accurate enough.

2. ## Osmotic pressure

Diagrams (some of the apparatus) Method To do this experiment we are going to put five different strengths of sugar solutions into test tubes (strengths listed later), which are being held by a test tube rack. We are then going to get all five of the potato chips (lengths and diameter listed later)

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