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Finding The Osmotic Point Of Equilibrium In A Potato

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Introduction

Osmosis Investigation Jade Hill Finding The Osmotic Point Of Equilibrium In A Potato The following Passages are information which I have managed to find when researching the topic of Osmosis: - The cell membrane controls the movement of substances going into and out of the cells. The cell therefore controls the Chemical composition of the internal environment of the cell. It does this in two ways; Passive Process - this does not require energy Active Process - this does require energy to occur This works in principle which diffusion in which molecules and ions in a solution move from an area of high concentration to an area of low concentration resulting in the equal distribution of molecules. Cells membranes are selectively or partially permeable, this means moving the membrane allows certain molecules to pass through it moving freely down the concentration gradient but not others. Osmosis The cell membrane is partially permeable in that it allows some molecules to diffuse rapidly but slows the passing of others. The glucose molecules try to diffuse to the outside but cannot get through the membrane because the pores are too small. The water molecules diffuse trough the pores down the concentration gradient. This membrane- controlled diffusion of water molecuse is controlled by osmosis, it can works both ways so that it can pass into and out of the cell. Osmosis and Diffusion If water is withheld from a flowering plant, the flowers wilt. If bacterial cells are placed in concentrated salt water solution, they collapse and die. ...read more.

Middle

Equilibrium is where the concentration of salt in the water (or environment ) is equal to the concentration of the salt in the potato. I will know where the point of equilibrium is because when this certain amount of water is added to the water the potato will not gain or lose any mass. This investigation is a piece or evidence to prove osmosis These diagrams explain the process of Osmosis; Jade Hill Osmosis Investigation Finding the Point Of Equilibrium In a Potato Aim The aim of this investigation is to find the point of osmotic eqauallibrium in a potato (where the concentration of salt in the potato is equal to the concentration of salt in the water and the potato does not gain or lose or lose any mass when this amount is added). Prediction I predict if you put the potato chip in a strong salt solution it will lose mass because the concentration of salt surrounding the potato is grater than the salt concentration in the potato. There for the water will diffuse out of the potato into the salt solution, this will make the potato chip flaccid. If I put the potato chip in a weak salt solution the potato will not lose or gain water because the concentration of salt in the potato will be equal to the concentration of salt in the solution. The potato will reach equilibrium so if the potato loses four water molecules it will gain four water molecules. ...read more.

Conclusion

using the top pan balance for accuracy. 4. Stir solution three times to dissolve the salt in the water. Method For Experiment Cut potato chips to desired mass ( in my case 40mm), measuring accurately. This can be done using the potato chip cutter and lining the chip up along side a ruler measuring the length of it. 1. Weigh out the salt portions (once for each percentage). 2. Measure out water required, this must be done very accurately for a fair result. 3. Once the salt and water is ready put the salt into the water at the same time, stir the water and salt three times to help dissolve it. 4. Cut 15 chips at 4cm. 5. Place all the chips in the water at the same time (using some assistance) to ensure a fair test and start timer. 6. Leave the beaker in a cool dry place for the 69 hours and 30 minutes. 7. After 69 hours and 30 minutes take each potato out of the water at the same time and wipe off excess water on paper towels by rolling the chips three times (this is again to ensure fair results are gained). 8. Weigh up the potato chips and record the results, this needs to be done very accurately (to ensure accuracy is achieved a top pan balance is used). Diagram for method Salt solution %age Weight before (gms) Weight After (gms) Average %age loss/gain Go1 Go2 Go3 Go1 Go2 Go3 1% 1.25 1.25 1.25 1.5 1.5 1.4 2% 1.25 1.25 1.25 1 1.1 1.2 3% 1.25 1.25 1.25 1.1 1.1 1.2 4% 1.25 1.25 1.25 1 1 1 5% 1.25 1.25 1.25 1 1.2 1 ?? ...read more.

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