📚 Topic Summary
Boiling point elevation is a colligative property, meaning it depends on the amount of solute present in a solution, not its identity. When a solute is added to a solvent, the boiling point of the solution increases compared to the pure solvent. This occurs because the solute particles interfere with the solvent's ability to vaporize, requiring a higher temperature to reach the boiling point.
The boiling point elevation ($ \Delta T_b $) can be calculated using the formula: $ \Delta T_b = i \cdot K_b \cdot m $, where $ i $ is the van't Hoff factor, $ K_b $ is the ebullioscopic constant (boiling point elevation constant) for the solvent, and $ m $ is the molality of the solution.
🧪 Part A: Vocabulary
Match the terms with their definitions:
| Term |
Definition |
| 1. Molality |
A. The increase in boiling point of a solution relative to the pure solvent. |
| 2. Ebullioscopic Constant |
B. A property that depends on the concentration of solute particles but not their identity. |
| 3. Boiling Point Elevation |
C. The number of particles a solute dissociates into in solution. |
| 4. Colligative Property |
D. Moles of solute per kilogram of solvent. |
| 5. Van't Hoff Factor |
E. The constant that relates molality to boiling point elevation. |
✍️ Part B: Fill in the Blanks
Complete the following paragraph using the words: solute, boiling point, solvent, elevation, temperature.
Boiling point _________ is the phenomenon where adding a _________ to a _________ raises the _________ of the solution. This means a higher _________ is required for the solution to boil compared to the pure solvent.
🤔 Part C: Critical Thinking
Explain in your own words why adding salt to water increases its boiling point. Use the concept of vapor pressure in your explanation.