Concentration and Solubility
📚 Key Concepts
🔹 What is Concentration?
Concentration tells us how much solute is present in a given amount of solution or solvent. It indicates the strength of a solution.
Types:
- Dilute solution: Less solute, more solvent
- Concentrated solution: More solute, less solvent
Real-life Examples:
- Strong tea: Concentrated solution (more tea powder)
- Weak tea: Dilute solution (less tea powder)
- Concentrated fruit juice: High concentration of fruit extract
- Diluted juice: Lower concentration after adding water
🔹 Saturated vs Unsaturated Solutions
Unsaturated Solution:
- Can dissolve more solute at that temperature
- Solution has not reached its maximum capacity
- Example: 1 spoon sugar in 1 glass water
Saturated Solution:
- Cannot dissolve any more solute at that temperature
- Maximum amount of solute has been dissolved
- Additional solute will remain undissolved
- Example: When sugar stops dissolving and settles at bottom
Supersaturated Solution:
- Contains more solute than normally possible
- Unstable solution, easily disturbed
- Created by special methods (heating then cooling)
🔹 Solubility
Solubility is the maximum amount of solute that can dissolve in a fixed amount of solvent at a particular temperature.
Factors Affecting Solubility:
- Temperature:
- For solids in liquids: Usually increases with temperature
- For gases in liquids: Usually decreases with temperature
- Example: More sugar dissolves in hot water than cold water
- Nature of solute and solvent:
- “Like dissolves like” principle
- Polar substances dissolve in polar solvents
- Non-polar substances dissolve in non-polar solvents
- Pressure:
- Mainly affects gas solubility
- Higher pressure = more gas dissolves
- Example: CO₂ in soft drinks under pressure
🧪 Important Relationships
🔸 More temperature → More solid solubility 🔸 More temperature → Less gas solubility 🔸 More pressure → More gas solubility