Diffusion Rate
- Diffusion Rate
CHEMICAL DIFFUSION IN AGAR
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Diffusion is a process of equalization which involves movement of molecules from an area of high concentration to an area of low concentration
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This exercise investigates diffusion as it applies to movement of particles in a semi-solid material called agar
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Molecules are in a constant state of motion
The motion of these molecules are influenced by many factors
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FACTORS INFLUENCING DIFFUSION
1) Kinetic Energy
2) Nature of the environment
3) Size of the molecules
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KINETIC ENERGY
The driving force which causes the molecules to move
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Click Mouse Here to Perform the Exercise on Chemical Diffusion in Agar
NATURE OF THE ENVIRONMENT
The agar environment we will be using is a semisolid material through which we will measure the rate of diffusion of substances with different molecular size
SIZE OF THE MOLECULES
Smaller molecules move faster than larger molecules
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Click Mouse Here to Perform the Exercise on Chemical Diffusion in Agar
You will need to supply the following in your lab review sheet for experiment #1
1) Data Table for Diffusion of Different Molecular Weights
2) Answers to questions 1-3
Procedure
- Obtain two test tubes with agar
*You can obtain the test tubes by clicking on the test tube rack on the shelf to the left
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Test tube rack
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Procedure
2) Mark the test tubes as
#1 and #2
*If you click on the pencil lying on the shelf to the left you can mark the tubes
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Procedure
3) Add a small amount of methylene blue to test tube #1
*You can click on the blue eyedropper lying on the shelf to the left to add the dye
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Procedure
4) Quickly click on the START button on the timer and record on your printed Data Sheet every 15 minutes the distance the dye has moved through the agar
*You can measure the progress of the dye by observing the mm marks on the test tubes
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START
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45:00
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55:00
60:00
Click here if you messed up and would like to try this experiment again
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Procedure
5) Add a small amount of potassium permanganate to test tube #2
*You can click on the green eyedropper lying on the shelf to the left to add the dye
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Procedure
6) Quickly click on the START button on the timer placed on the table and record every 15 minutes the distance the dye has moved through the agar
*You can measure the progress of the dye by observing the mm marks on the test tubes
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2
START
00:00
05:00
10:00
15:00
20:00
25:00
30:00
35:00
40:00
45:00
50:00
55:00
60:00
Click here if you messed up and would like to try this experiment again
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DATA
At this point you should have collected diffusion distance data for methylene blue and potassium permanganate
Complete the questions on your review sheet using the Data Table for Diffusion of Different Molecular Weights
At this point you have finished experiment #1 for this lab
Continue to experiment #2 (OSMOSIS AND DIALYSIS)