Final answer:
Beaker A contained the 10% sugar solution, as water moved into the comparatively hypertonic 20% sugar solution in the dialysis tubing. Beaker B contained the 20% solution due to no mass change, suggesting an isotonic state. Beakers C and D had to be the 15% and 30% solutions, respectively, with C having lower concentration than the tubing's and D having a higher concentration.
Step-by-step explanation:
According to the principles of osmosis, water moves across a semipermeable membrane from an area of lower solute concentration (hypotonic) to an area of higher solute concentration (hypertonic). The dialysis tubing in the experiment is only permeable to water, not sugar, resulting in changes in the mass of the tubing due to the movement of water in or out of the tubing.
The tubing in beaker A gained mass, indicating that water moved into the tubing, which means beaker A contained a solution that was more dilute than the 20% sugar solution in the tubing. Therefore, beaker A contains the 10% sugar solution. The tubing in beaker B remained the same, suggesting that the concentration inside the tubing and the beaker was in equilibrium; hence, beaker B contained the 20% sugar solution.
Beaker C's tubing gained even more mass than A's, indicating that beaker C was even more dilute than A and was pure water. Therefore, beaker C had no sugar, but as it is not one of the options, we disregard this in favor of the known concentrations. The tubing in beaker D lost mass, signifying that water moved out of the tubing into a hypertonic solution, which means that beaker D contained the 30% sugar solution. Following the process of elimination, beaker C, which had the highest water mass gain, contained the 15% sugar solution.