Period: 6
09/11/12
Osmosis Lab
I. Objective: The purpose of this lab is to put the solutions in chronological order from least to most molarity. If the solutions are hypertonic then, the water will go in and the order of the substances will be C, D, A, B, E.
II. Materials and Methods: See attached page.
Results: Table 1.1
III. Table 1.1 | Initial | Final | % Change | A | 11.4 | 11.86 | 4.03% | B | 11.67 | 15.33 | 33.68% | C | 10.84 | 11.86 | 9.4% | D | 12.02 | 12.0 | 24% | E | 11.33 | 13.39 | 18.18% | Water Color | 10.91 | 10.71 | 1.8% |
Example: 11.86-11.4= 0.46/ ll.4 = 0.04035 x 100= 4.03%
IV. Discussion:
Based on the percentage changed on table 1.1 we can conclude that the experiment overall
was hypotonic and the dialysis tubing were hypertonic. This means that the water went inside the dialysis tubing; went from a hypotonic to a hypertonic solution. There are some possible sources of error; one of them might have been that the solutes were divided among different groups and each group had a solute with different amount of molarity.. Another source of error might have been that while measuring the amount of water was more or less than it had to be. Also a possible source of error could have been weighing the solutes before and after the experiment. To prevent experimental errors for future experiments what can be done is to do the whole experiment with our own results. Another way of avoiding errors is to do a number of trials for the results to be more accurate. My hypothesis was proven right by the overall results because the water went inside the dialysis tubing. After the experiment was finish I was surprised to see all the experimental errors that were done. Overall, I learned that sources of error are possible when working on an experiment. Also, that in order to obtain more accurate results experiments should be done by one person.
Pre-lab
Materials: 1. Electronic balance 2. 5 dialysis tubes 3. Water 4. 2 beakers 5. Sucrose solutions
Procedures: 1. Label beakers A-E and add 150mL of water to each of them. 2. Submerge the dialysis tube in water to allow it to open up. 3. Tie the bottom of each dialysis tube. 4. Pour 10mL of solution A into dialysis tube. 5. Release all air and tie it at the top. 6. Weight the dialysis tube and record the weight on table 1.1. 7. Repeat steps 2-6 for remaining solutions (B-E). 8. After 30-40 minutes take dialysis tubes out of the water and wipe off excess water. 9. Weight each dialysis tube using the electronic balance and record results on table 1.1. 10. Calculate percent changed in mass for each tube.