Work in groups of 3. Cut five 10-cm lengths of dialysis tubing and soak them for
ID: 97863 • Letter: W
Question
Work in groups of 3. Cut five 10-cm lengths of dialysis tubing and soak them for 5 - 10 minutes in water until they are pliable. Tie a knot in one end of each piece of dialysis tubing to form 6 bags. Pour approximately 5 - 15 mL of each of the below solutions into the separate bags. Remove most of the air from each bag by drawing the dialysis bag between two fingers. Tie off the other end of the bag. Leave sufficient space for the expansion of the contents in the bag. (The solution should fill only about one-third to one-half of the piece of tubing.) The filled bags will serve as models of a cell. Each group member should be given two solutions to be responsible for throughout the exercise. a) 0.0 M sucrose (distilled water) b) 0.3 M sucrose c) 0.6 M sucrose d) 0.9 M sucrose a) Unknown M Rinse each bag gently with distilled water to remove any sucrose spilled during the filling. Carefully blot the outside of each bag and record in Table 4 the initial mass of each bag, expressed in grams. Place each bag in an empty 250-mL beaker or cup and label the beaker to indicate the molarity (M) of the solution in the dialysis bag. Now fill each beaker two-thirds full with distilled water. Be sure to completely submerge each bag. Let them stand for 30 minutes. At the end of 30 minutes remove the bags from the water. Carefully blot and determine the mass of each bag. Remember to tare the scale before each measurement, and use the plastic weight boats to hold your tube when it's on the scale. Record your group's data in Table 4. Percent change in mass = (final mass - initial mass)/initial mass Share data with 3 other groups to determine an average percent change in mass for all solutions. Create a line graph of your data, with concentration on the x-axis and average percent change on the y-axis. Draw a horizontal line from the y-axis at the value of the unknown solution to the trend line in your graph. Then draw a vertical line to the x-axis to figure out the concentration of the unknown solution. This is called interpolation of a value. Explain the relationship between the change in mass and the molarity of sucrose within the dialysis bags. Predict what would happen to the mass of each bag in this experiment if all the bags were placed in a 0.4 M sucrose solution instead of distilled water. Explain your response. Why did you calculate the percent change in mass rather than simply using the change in mass? A dialysis bag is filled with distilled water and then placed in a sucrose solution. The bag's initial mass is 20 g and its final mass is 18 g. Calculate the percent change of mass, showing your calculations. The sucrose solution in the beaker would have been ____ to the distilled water in the bag. Circle the word that best completes the sentence: isotonic/hypertonic/hypotonic. Interpolate using your graph: What is the molarity of Unknown Solution 1?Explanation / Answer
Answer:
14.The change in mass and the molarity of sucrose within the dialysis bag are directly proportional. The percent change of mass goes up as the molarity of the sugar goes up.
15. There will be no net movement when the concentration of the sucrose solution in the dialysis bag is 0.4M. The bag will loose water when the concentration of sucrose in the bag is more than 0.4M and gain water when the concentration of sucrose in the bag is less than 0.4M.
16. The percent change in mass was calculated since the volumes of the solutions in the dialysis bags were different.
17. Percent Change in Mass = {(Final Mass - Initial Mass) / Initial mass} x 100 = {(18 - 20) / 20} x 100
= (2 / 20) x100 = 10%
(Since there are multiple sub-parts, the first 4 sub-parts have been answered according to the rules of Chegg)
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