Three Lab Groups Carried Out an Experiment to Identify the Concentration

question 66

Multiple Choice

Three lab groups carried out an experiment to identify the concentration of sucrose in six solutions. Each unknown contained one of the following sucrose concentrations: 0.0 M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, and -1.0 M. Cubes of sweet potato (1 cm³) were soaked for 24 hours in each solution and weighed to determine the change in mass. Each data entry represents the average of three sample replicates expressed as percent change in mass following a 24-hour soak in the unknown solutions. From the data given, which statement most accurately describes what is occurring in response to a particular unknown solution?
$$\begin{array} { | l | l | l | l | } \hline \text { Unknown } & \text { Percent change in } & \text { Percent change in } & \text { Percent change in } \\& \text { Graup 1 } & \text { Guss } & \text { mass } \\\hline \text { A } & 6.6 & 7.8 & \text { Group 3 } \\\hline \text { B } & 3.1 & 3.7 & 7.5 \\\hline E & - 2.7 & - 3.5 & 2.9 \\\hline \text { D } & 0.7 & 0.5 & - 2.5 \\\hline \text { E } & - 11.6 & - 12.3 & 1.1 \\\hline & - 5.2 & 6.2 & - 12.6 \\\hline\end{array}$$

• A) Unknown solution E contains the highest concentration of sucrose, and the change in mass is due to the active transport of sucrose out of the cell.
• B) Osmosis of water molecules from unknown solution B likely caused the increase in mass observed.
• C) Passive transport of sucrose out of the potato cells explains the change in mass observed for unknown solution F.
• D) Unknown solution C represents a sucrose concentration slightly higher than the molarity of sweet potato cells, thus water is transported out of the cells.

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