The latent heat of vaporization is the amount of heat energy required to change a substance from a liquid to a gas without changing its temperature.
For instance, When water on a stove reaches its boiling point, the additional heat added is used to break the bonds between water molecules, turning liquid water into steam.
The latent heat of vaporization has real-world applications in various fields and is crucial for understanding phase transitions and designing energy-efficient systems.
The mathematical form is given as:
Q=m⋅L
where:
- Q is the heat energy absorbed,
- m is the mass of the substance, and
- L is the latent heat of vaporization.
Real Life Examples
- Boiling Water: Heating turns water into steam, absorbing latent heat.
- Refrigeration: Refrigerants change from liquid to vapor, absorbing heat.
- Sweating: Sweat evaporates, cooling the body by absorbing heat.
- Food Cooking: Heat causes water in food to vaporize, affecting texture and flavor.
- Steam Engines: Steam engines use heat to produce steam, driving a piston.
- Drying Clothes: Wet clothes dry as water evaporates, absorbing heat.
- Cloud Formation: Water vapor condenses into clouds, releasing latent heat.
- Freezing/Thawing Lakes: Lakes freeze/thaw, involving latent heat in the process.
Important Points
- Latent heat is substance-specific.
- Energy is absorbed during vaporization and released during condensation.
- It is critical in designing efficient cooling and heating systems.
Simple Case Study
Scenario: Boiling 2 kg of water to steam.
Calculation: Q=m⋅L
Q=2 kg×2260 kJ/kg=4520 kJ
