1. You prepare three bags containing different sucrose solutions (A = 15%, B = 30%, C = 65% sucrose). After weighing the bags you record their masses in the table. You then place your bags in beakers, all containing the same unknown concentration of sucrose and let them sit for one hour. Every 15 minutes you take the bags out and record their mass (Table 1). IL 10 0.41 A B B 1 Table 1:

Mass (g) of bags A, B, and C, over time (min). Time (min) Mass of A () Mass of B (8) Mass of C (8) 0 12.4 11.6 12.1 15 10.4 11.2 12.9 30 9.1 10.9 13.8 45 7.7 10.4 14.7 6.2 10 60 15.9 b. The pattern of change in mass was similar in bags A and B. However, the change was greater in bag A than in bag B. How do you explain the difference? Can you predict what the expected range of concentrations must be for the beaker solution? c. Calculate the percent change in mass for each bag according to the formula below and fill in the answers in table 2. %

change in mass mass current time - mass time zero x 100% mass time zero Table 2: Percent change in mass of bags A, B, and C, over time. Time (min) % change in mass of A % change in mass of B % change in mass of C 0 15 30 45 60 d. Graph the percent change in mass over time in the graphing area provided below. You will need to correctly label and divide up the X and Y axes, plot the data coordinates, draw a line of best fit for each data set, and add in a legend to differentiate between the 3 lines for the bags.

e. Determine the rate of change in mass (slope) for each solution over the entire 60 minutes and enter your results in Table 3. y2-yi Slope x2-31 Slope of line A: %/min Slope of line B: %/min Slope of line C: %/min Table 3. Sucrose concentration in bags A, B and C vs. Rate of mass change over 60 minutes. Sucrose concentration Rate of mass change over time (%/min) 15% (A) 30% (B) 65% (C)

f. Graph the rate of change in mass versus sucrose concentration. g. Bags A and B both lost mass over the 60 minutes, but the rate of mass change in A was faster than in B. How is this evident from the graph above and what does it suggest about these solutions? h. Determine the isotonic concentration of sucrose. Remember, the isotonic concentration is that at which no net osmosis is happening and therefore the rate of change in mass or rate of osmosis is equal to zero. 1. What is the concentration of the solution in the beakers? Explain.