Four Laws of Thermodynamics

These flashcards cover key concepts and definitions related to the Four Laws of Thermodynamics, including significant laws, energy terms, and processes.

Zeroth Law of Thermodynamics

States that if two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other.

First Law of Thermodynamics

The internal energy of an isolated system is conserved, represented by the equation dU = ¯dQ + ¯dW.

Internal Energy (U)

The total energy contained within a system, which can change during heat transfer and work.

Heat (Q)

An energy transfer process owing to a temperature difference.

Work (W)

An energy transfer process involving a force acting through a distance.

Sign Conventions

Q is positive if the system is heated by its surroundings and negative if the surroundings are heated by the system; W is positive if work is done on the system, negative if done by the system.

Pressure-Volume Work

Work done by or on a gas during compression or expansion, calculated as W = -∫ pdV.

Quasistatic Process

A thermodynamic process that occurs slowly enough that the system remains in equilibrium.

Thermal Equilibrium

A state where two systems have the same temperature and no heat flows between them.

Differentials in Thermodynamics

dU is a perfect differential, while dQ and dW are imperfect differentials that depend on the path taken.