Thermodynamics Flashcards
Closed system
A system with constant mass
Open system
A system with variable mass
Reversible process
Force can be applied in the opposite direction such that the system and surroundings can be restored to their initial equilibrium state
Intensive properties
Independent of mass (ex pressure and temperature)
Extensive properties
Dependent on mass (volume, internal energy, enthalpy)
Potential energy
Energy due to a object’s position in a gravitational field
Kinetic energy
Energy associated with motion
Internal energy (U)
Energy due to the position and movement of a system’s molecules
Heat energy (Q)
Energy transferred across the boundary of a system due to temperature difference
Work (W)
Force x distance, a form of energy transfer
Enthalpy (H)
Total heat content of a system, U + PV
First Law of Thermodynamics
Conservation of energy- energy can neither be created nor destroyed
Second Law of Thermodynamics
The entropy of a system always increases
Third Law of Thermodynamics
The entropy of a system approaches a constant value as the temperature approaches absolute zero
Carnot cycle
A theoretical ideal cycle in which the max amount of heat is converted to work, but some energy is still lost
When processes are reversible and adiabatic…
… entropy remains constant
When heat is added, entropy…
…increases
Isentropic
Reversible and adiabatic
Ideal gas law
intramolecular forces are negligible because volume occupied by a gas is so large
Actual gases obey the ideal gas law when…
… pressure is low and temperatures is high
Conduction
transfer of heat by direct contact
Convection
transfer of heat through movement of fluids
Radiation
energy is emitted in the form of photons or electromagnetic waves
