Biology – 3.2 Osmosis | e-Consult
3.2 Osmosis (1 questions)
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Dialysis tubing is used in osmosis investigations because it is a semi-permeable membrane. This means that it allows the passage of some molecules (like water) but blocks the passage of others (like larger solute molecules). This selective permeability is crucial for demonstrating osmosis, as it allows water to move across the membrane while restricting the movement of the solute.
Properties of Dialysis Tubing:
- Semi-permeable:** Allows water molecules to pass through but restricts the passage of larger solute molecules.
- Porous:** Contains tiny pores that allow water molecules to diffuse through.
- Consistent Pore Size:** Dialysis tubing is manufactured to have a consistent pore size, ensuring that water can pass through relatively easily.
- Inert:** The material of the tubing (usually cellulose) is generally inert and does not interact with the substances being investigated.
Limitation of Dialysis Tubing:
- Pore Size Limitations: The pore size of the dialysis tubing can sometimes be too large, allowing some small solute molecules to pass through along with the water. This can lead to inaccurate results, as the movement of these small molecules can affect the osmotic pressure. Alternatively, the pores can be too small, hindering the rate of osmosis.