Temperature's Effect on Diffusion:
We added potassium to a two tubes with different temperatures:
Temperature Result
Room Temperature Slow change in Color
Boiled water Fast change in Color
Conclusion : The increase in temperature assists in increasing the speed of diffusion.
Diffusion of Glucose and Starch: A. Color Change:
State/Results
In the Tube In the Beaker
Color Glucose Color Glucose
Initial State (Before placing tube into graduated cylinder) Transparent Yes Transparent No
Final State Orange Yes Orange Yes 1. No, the Starch did not. Because once we added Iodine to the Beaker the color did not change.
2. No, because the color inside the tube did not change.
3. Yes Glucose moved out of the tube. The color changed from transparent to orange.
The Effect of Weight on Diffusion:
Molecule Molecular Formula Did it cross selectively permeable membrane
Starch Polysaccharide made up of many Glucose molecules No
Glucose C6H12O6 Yes
The Effect of Weight on Diffusion's Speed:
We put 3 elements in a TSA plate and left them for 30 minutes to see where diffusion is faster, the results are:
1. Potassium permanganate KMnO4: Mw= 158.034 g/mol [Fast]
2. Methylene Blue: Mw= 319.85 g/mol [Medium]
3. Malachite Green: Mw= 364.9 g/mol [Slow]
Conclusion: the lighter the molecular weight is, the faster the diffusion gets.
The Starch did not pass through the membrane because it is composed of Polysaccharide made up of many Glucose molecules, which makes it heavier than one single Glucose molecule to pass through. Osmosis:
We took three piece of potato and placed them in three beakers with the same quantity of water but with different concentrations, results are:
Solution Result
0.9% NaClNothing happens
H2O Hypotonic : Potato Swells
30% NaClHypertonic: Potato Shrinks