In the experiment where a container is partitioned by a semi-permeable membrane with a solution on one side and pure solvent on the other, both compartments open to the atmosphere, the following is expected: The solvent (usually water) will move from the pure solvent compartment (where solvent concentration is higher) to the solution compartment (where solute concentration is higher) across the semi-permeable membrane. This movement of solvent is called osmosis. The semi-permeable membrane allows only the solvent molecules to pass through but not the solute molecules. Because both sides are open to the atmosphere, pressure will not build up indefinitely. Instead, the solvent will move into the solution compartment, causing a slight change in volume or level in the compartments. Eventually, an equilibrium will be reached where the net movement of solvent stops. This happens because the solvent tends to move to equalize concentration but the atmospheric pressure counterbalances the osmotic pressure. In summary:
- Solvent moves from the pure solvent side to the solution side by osmosis.
- This happens because solvent concentration is higher on the pure solvent side.
- The semi-permeable membrane blocks solute movement, allowing only solvent passage.
- Both compartments open to atmosphere prevent pressure buildup.
- Equilibrium is reached when the osmotic flow is balanced by atmospheric pressure.
This is a typical demonstration of osmosis driven by concentration differences across a semi-permeable membrane.
