Question

Read the following passage and answer the following questions.
Dialysis tubing is a semipermeable membrane. It allows small molecules, such as water, to pass through easily, while larger molecules, such as sucrose, are restricted. Movement of molecules across the tubing is due to concentration gradients. In an experiment designed to study osmosis, several pieces of dialysis tubing were filled with sucrose solutions of varying concentration and placed in beakers containing distilled water. The rate and direction of water movement was determined by weighing the bags before and after placing them in the distilled water. The data are recorded below.
Table 1

Tube number	Tube contents (beaker contents)	Mass(g) 0 minutes	Mass(g) 15 minutes	Mass (g) 30 minutes	Mass(g) 45 minutes	Mass (g) 60 minutes
1	Distilled water (distilled water)	22.3 g	22.4 g	22.2 g	22.3 g	22.3 g
2	10% sucrose (distilled water)	24.8 g	25.3 g	25.7 g	26.4 g	26.9 g
3	40% sucrose (distilled water)	25.1 g	26.3 g	27.5 g	28.9 g	29.6 g
4	Distilled water (40% sucrose)	22.7 g	21.3 g	20.5 g	19.8 g	18.7 g

Why does the mass of Tube 3 increase while the mass of Tube 4 decreases?

• A. Water is moving into Tube 3, and sucrose is moving into Tube 4.
• B. Water is moving into Tube 4, and sucrose is moving into Tube 3.
• C. Water is moving into Tube 3, and water is moving out of Tube 4.
• D. Sucrose is moving into Tube 3, and sucrose is moving out of Tube 4.
• E. Sucrose is moving out of Tube 3, and water is moving out of Tube 4.

Answer 1

The correct option is C Water is moving into Tube 3, and water is moving out of Tube 4.

In tube 3, water molecules are moving towards higher concentration i.e., from beaker to tube content, thus the mass increases but in case of tube 4, water is moving out from tube contents to beaker, as the beaker contains more concentrated solution. Thus, the correct answer is 'Water is moving into Tube 3, and water is moving out of Tube 4.'