Problem 1: Diffusion
Define the following terms
- Solvent
- Solute
- Solution.
- Diffusion
- Concentration gradient
- Dynamic equilibrium
Problem 2 – Factors influencing rate of diffusion
Predict how molecule size and temperature will affect the outcome of this experiment
Record the data from the information in the lab
What effect did temperature have on the rate of diffusion
How did molecule size affect the rate of diffusion
Problem 3: Effect of solute concentration on rate of osmosis
Subtract the beginning mass from the final mass for each of the five bags. Record the difference in the table below:
Problem 4: Plasmolysis in Elodea cells
Label which sample is turgid and which is plasmolyzed (Answer 1 in each column). Label the cell wall, central vacuole, plasma membrane, and chloroplasts on each slide. For a more detailed view of the slides below, increase the document size to 150%
Problem 5: Tonicity in red blood cells
Record your observations for each tube in the table below
Summary Questions:
1. Compare diffusion and osmosis. Give an example of each.
2. In which direction will osmosis occur if a 15% sugar solution is separated from a 25% sugar solution by a differentially permeable membrane?
3. Why did osmosis, but not diffusion of sucrose molecules, occur across the dialysis membrane containing 20% sucrose solution?
4. You are having a party and the celery has become limp. What might you do to make the celery crisp (turgid) again? What is occurring in the cells?
5. A small amount of fertilizer (mineral salts) will stimulate plant growth, but over fertilization can kill plants? Why?
6. A person aIDs sugar to coffee. Explain what in this drink is the solvent, solute, and solution.
7. You aID a cube of sugar to your drink. How could you speed up the diffusion of sugar molecules without stirring?
8. How is dynamic equilibrium established within a solution?
9. How is an unknown solution tested for the presence of starch?
10. How would an unknown solution be tested for the presence of chloride ions?
