PURPOSE:
The purpose of the osmosis lab is to determine the relative molarity of an unknown sugar solution to other sugar solutions of varying molarities. This is possible due to the process of osmosis, in which water always diffuses into a solution that contains less water and more solute. The independent variable is the mystery solution in the dialysis tubes, and the dependent variable is their respective molarities.
This lab is related to the unit on Cell Structure and Function, as it shows us how the transfer of materials occurs in our cells though osmosis in hypertonic and hypotonic solutions and how our body maintains homeotasis and isotonicity.
HYPOTHESIS:
If the mystery solution in the dialysis tubing gains mass, than it was hypertonic relative to its surrounding solution, while if the solution loses mass, than it is hypotonic relative to its surrounding solution. If the solution retains a constant mass, than it is isotonic compared to the other solution.
METHODS SUMMARY:
IV: The IV is the mystery solution.
DV: The DV is the relative molarity of the mystery solution.
Measurement: The DV is measured by measuring the change in mass of each dialysis tube.
Control: The control is a plain water solution.
Constant: Molarity of mystery solution
Number of trials: 1
MATERIALS:
1. 4 Beakers
2. 4 Dialysis Tubes
3. Water
4. Sugar
5. 4 Different Colors of Food Coloring
6. Stopwatch
PROCEDURE:
1. Soak dialysis tubes to prepare them
2. Fill all 4 tubes with the mystery solution of sugar water
3. Record the initial mass of each tube
4. Fill 3 beakers with a different sugar water solution each.
5. Fill one beaker with plain water to act as the control
6. Drop 1 tube of mystery solution in each beaker
7. Let each tube soak in the solutions for 15 minutes
8. Take out each tube and dry them off
9. Record the final masses of the dialysis tubes.
10. Compare pre-experimental and post-experimental data to determine the relative molarity of the mystery solution to the sugar water solutions.
The purpose of the osmosis lab is to determine the relative molarity of an unknown sugar solution to other sugar solutions of varying molarities. This is possible due to the process of osmosis, in which water always diffuses into a solution that contains less water and more solute. The independent variable is the mystery solution in the dialysis tubes, and the dependent variable is their respective molarities.
This lab is related to the unit on Cell Structure and Function, as it shows us how the transfer of materials occurs in our cells though osmosis in hypertonic and hypotonic solutions and how our body maintains homeotasis and isotonicity.
HYPOTHESIS:
If the mystery solution in the dialysis tubing gains mass, than it was hypertonic relative to its surrounding solution, while if the solution loses mass, than it is hypotonic relative to its surrounding solution. If the solution retains a constant mass, than it is isotonic compared to the other solution.
METHODS SUMMARY:
IV: The IV is the mystery solution.
DV: The DV is the relative molarity of the mystery solution.
Measurement: The DV is measured by measuring the change in mass of each dialysis tube.
Control: The control is a plain water solution.
Constant: Molarity of mystery solution
Number of trials: 1
MATERIALS:
1. 4 Beakers
2. 4 Dialysis Tubes
3. Water
4. Sugar
5. 4 Different Colors of Food Coloring
6. Stopwatch
PROCEDURE:
1. Soak dialysis tubes to prepare them
2. Fill all 4 tubes with the mystery solution of sugar water
3. Record the initial mass of each tube
4. Fill 3 beakers with a different sugar water solution each.
5. Fill one beaker with plain water to act as the control
6. Drop 1 tube of mystery solution in each beaker
7. Let each tube soak in the solutions for 15 minutes
8. Take out each tube and dry them off
9. Record the final masses of the dialysis tubes.
10. Compare pre-experimental and post-experimental data to determine the relative molarity of the mystery solution to the sugar water solutions.
DATA TABLE:
DATA CHART:
![Picture](/uploads/3/0/4/8/30484494/7774998.png?600)
The change of mass occurs due to the diffusion of water across the semipermeable dialysis tubing. Each tube had a varying amount of mystery solution, but the molarity is constant in each tube. Relative molarity can be determined by observing the percent change in the mass of each solution.
CONCLUSION:
The data indicated that the blue solution was hypertonic to the mystery solution, while the other solutions were hypotonic to the mystery solution. This indicated that the mystery solution had a molarity higher than the green, yellow, and control solutions, while its relative molarity was lower than the blue solution. This explanation supports the hypothesis that the tubes will gain mass when placed in a hypotonic solution and that they will lose mass when placed in a hypertonic solution. The solution closest to being isotonic with the mystery solution was the green solution. However, after the experiment, we learned that the mystery solution was simply plain water. This indicated that there were possible errors in the data. The mystery solution should have been isotonic in the control. It was possible that the water in each solution had different minerals, which contributed to osmosis. It was also possible that the tubes were not completelt dried, thus adding extra mass to the tubes. In order to remedy these issues, water should be gathered from the same source, and dialysis tubing must be dried thoroughly.