Summary
Partition coefficients describe the distribution of a substance between two immiscible liquids in a separating funnel, where a dynamic equilibrium is established. The partition coefficient is a ratio that indicates how a substance is distributed between two layers.
- Partition Coefficient (Kpc) — ratio of concentrations of a solute in two immiscible solvents at equilibrium. Example: If 1.00g of X is in 100cm³ of water and 5cm³ of ether, Kpc = 40, showing X is more soluble in ether.
- Dynamic Equilibrium — state where the rate of transfer of a solute between two layers is equal in both directions. Example: X(in more dense liquid) ⇋ X(in less dense liquid).
Exam Tips
Key Definitions to Remember
- Partition Coefficient (Kpc)
- Dynamic Equilibrium
Common Confusions
- Confusing the direction of solute movement between layers
- Forgetting that the partition coefficient has no units
Typical Exam Questions
- What is a partition coefficient? It is the ratio of concentrations of a solute in two immiscible solvents at equilibrium.
- How do you calculate the partition coefficient? By dividing the concentration of the solute in one solvent by its concentration in the other.
- Why does the partition coefficient have no units? Because the units cancel out when calculating the ratio.
What Examiners Usually Test
- Understanding of how to calculate and interpret partition coefficients
- Ability to explain dynamic equilibrium in the context of partitioning