Thermo Definitions Flashcards
What is Work?
Work is energy done over a distance.
What is a System?
A collection of particles, OR a region in space.
What is Density?
Mass per volume of a substance.
What is Specific Volume?
Volume per mass of a substance; it’s just the reciprocal of Density.
What variables does Temp depend on?
Temp depends upon the internal energy of the substance.
What variables does Pressure depend on?
Pressure depends on kinetic energy plus mass density of the substance.
What is a state?
The state is a description of the conditions of the system - pressure, volume, mass, temperature, composition.
How does the density of the following materials change:
Solids
Liquids
Gases
Solids and liquids are nearly incompressible, but gases are highly compressible.
What is equilibrium?
A static system that experiences no change and has no unbalanced potentials.
What is the state postulate?
for a simple compressible system
The postulate that a simple compressible system can be completely described by two independent, intensive variables.
What is a simple compressible system?
A system that neglects gravitational, electromagnetic, motion, and surface tension effects
For a simple compressible system, what are the three intensive and two extensive properties?
Intensive:
Temp
Pressure
Density/Spec Volume
Extensive:
Volume
Mass
What is a process?
A change in a thermodynamic system that takes it from one state to another.
What are isobaric, isothermal, and isochoric processes?
Isobaric: a constant-pressure process
Isothermal: constant-temp
Isochoric: Constant spec vol or density.
What is a quasi-equilibrium process? What’s an example?
A process that occurs slowly enough so that the system doesn’t leave equilibrium.
e.g. squeezing a piston. Do it quickly, and a high-pressure region develops by the piston head. Slowly, though, and the molecules will be able to redistribute themselves.
