First Law of Thermodynamics
The First Law of Thermodynamics states that energy cannot be created or destroyed, only converted from one form to another. It is a statement of conservation of energy.
Mathematical Expression
The First Law can be expressed as:
Where:
- ΔU = change in internal energy
- Q = heat added to the system
- W = work done by the system
Key Concepts
- Internal Energy (U) is a state function
- Heat (Q) is positive when added to system
- Work (W) is positive when done by system
- Path independence of ΔU
Applications
- Heat engines and power plants
- Refrigeration systems
- Industrial processes
- Natural phenomena