Topic 6: One-Page Revision Sheet

Chapter 8: Thermodynamics – One Page Revision

1. Thermodynamics

Branch of physics dealing with relationship between heat, work and internal energy.

2. Thermodynamic System

Part of universe chosen for study.

Surroundings

Everything outside the system.

Boundary

Surface separating system and surroundings.

3. Types of Systems

• Open system – exchanges matter & energy
• Closed system – exchanges energy only
• Isolated system – exchanges neither

4. Thermodynamic Process

Change in state of system due to heat or work interaction.

Types of Processes

• Isothermal – temperature constant
• Adiabatic – no heat exchange
• Isobaric – pressure constant
• Isochoric – volume constant

5. First Law of Thermodynamics

Heat supplied to system = increase in internal energy + work done by system.

Formula:
Q = ΔU + W

Sign Convention

• Q positive → heat supplied
• W positive → work done by system

6. Special Cases of First Law

• Isothermal: ΔU = 0 → Q = W
• Isochoric: W = 0 → Q = ΔU
• Adiabatic: Q = 0 → ΔU = −W

7. Isothermal Process

• Temperature constant
• Slow process
• Heat exchange occurs

8. Adiabatic Process

• No heat exchange
• Rapid process
• Temperature changes

9. Important CET Points

• Definitions of system and surroundings
• Classification of thermodynamic systems
• Identification of thermodynamic processes
• Numericals using Q = ΔU + W
• Difference between isothermal and adiabatic processes