Introduction to Thermodynamics Flashcards
What is equilibrium?
A condition of a thermodynamic system when it does not have a net transfer of mass, energy or momentum with the surroundings and all macroscopic properties of the system do not change over the duration of interest: DA/dt = 0, always at steady state
What is steady-state?
A condition of a thermodynamic system when all macroscopic properties of the system do not change over the duration of interest, not always at equilibrium, transfer can still occur but without changes in properties (bath tub example with drain)
What is work?
the force acting through a distance, dl
What is positive work?
the work is done on the system
What is negative work?
the work is done on the surroundings
What is work equal to?
F*(delta L)
What is heat?
Q, always flows from high to low temperatures, is in transit and is stored as the Ep and Ek of the atoms and molecules of system
Q>0
system absorbs heat
Q<0
system releases heat
What is internal energy?
microscopic energy change as a result of heat transfer, U
What is Gibbs phase rule?
F = C - P + 2 P = number of phases in equilibrium C = number of chemically independent components
What are degrees of freedom?
number of intensive variables needed to fully define a thermodynamic state
What is a reversible process?
one that is idealized (not reality) where the system is at equilibrium at any moment
infinitely slow
occur when the change in state variables are infinitely small
facilitate solving real-life, irreversible thermo problems
What is a path variable?
describes the change of a system from one state to another like Heat and Work
What is a state variable?
independent of the process and define conditions at the thermodynamic (equilibrium) state
