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Membrane Function practical

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Introduction

Membrane Function Planning A [Problem] Demonstrate the process of osmosis through a semi-permeable membrane. [Aim] To use a chicken egg as a model to demonstrate the process of osmosis [Hypothesis] The rate of osmosis increases, the concentration of the solution decrease. As we know the Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration. So if the solute concentration idecreases, the rate of osmosis increases. Planning B [Variables] Independent variable The concentration of the solution (the egg goes in) Dependant variable The weight of the egg Controlled variable .the same electronic balance .the same egg .the same stop watch .the same spoon to help .the distilled water from same bottle .the same measuring cylinder .the same room temperature [Materials] . 1 egg which remove the shell already . Spoon . 300ml 10% NaCl solution . 300ml 5% NaCl solution . ...read more.

Middle

10 Use the measuring cylinder to measure 150ml distilled water. 11 Put them in the beaker. Place the egg in the beaker gently so that it s fully covered and leave it for 10minutes.use a stop watch to help. 12 Take the egg out of the solution carefully use the paper towel to dry it. Then place the egg on the balance and record its mass in the data table. Calculate the change in mass and also enter this in the table. Also record any other observation. 13 Collect the class data and also tabulate this. 14 When finish the practical return the egg as instructed. Data collection [Results] A table showing the relationship between the solute concentration and the egg's weight changes Group/weight(g) Initial After 5% After 10% After 0% 1 65.862 66.636 66.734 68.263 2 75.429 74.593 73.233 73.909 3 72.132 72.122 71.204 72.770 4 62.64 63.563 64.696 65.896 5 62.81 63.75 64.37 65.56 6 65.66 66.68 67.2 68.07 7 67.85 68.82(7%) ...read more.

Conclusion

There is still some water there. This will make the weight change. 5 The equipment is not very accurate. This can affect the errors. 6 When you measure the solution, you use a measuring cylinder. So there will always leave some solution on the side. When you get the 5% solution, the concentration might not be right. 7 The room temperature won't be same, it will always get change. This will make the movement of the water become quicker or slower. Improvements 1 Try to let the egg to stay in HCl longer to remove all the shell. 2 Use the high quality solution. Prepare the 5% 10% and 0% solution. 3. Clean the balance each time before you weight the egg. 4. Try to use the paper towel to dry longer. This can help to remove most of the solution on the surface. 5 To do more times to get an average, this can help the result mot accurate. 6 Use high quality equipment instead of the measuring cylinder. 7 Try to keep the room temperature always same. Use a air condetional to help. ...read more.

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