Exam 1 Flashcards
What does the first law of thermo define?
Define Internal Energy and introduces enthalby
What is Internal Energy (U)?
The total capacity for heat transfer and work in the system
What does the 2nd law of thermo define?
Entropy (S)
What is Entropy?
A measure of molecular randomness in a system
What is an intensive property? Give examples
Independent of amount of mass.
E.g.: Density, Temperature, Pressure
What is an extensive property? Give examples
Dependent on amount of mass in a system.
E.g.: Volume, mass, total energy
What property is held constant in ISOBARIC PROCESS?
Pressure
What property is held constant in ISOTHERMAL PROCESS?
Temperature
What property is held constant in ISOCHORIC (OR ISOMETRIC) PROCESS?
Volume
What property is held constant in ISOENTROPIC PROCESS?
Entropy (S)
Gage Pressure
Pgage = Pabs - Patm
Vacuum Pressure
Pvac = Patm - Pabs
Define Macroscopic form of energy and give examples
The energy of system as a whole with respect to some outside reference frame.
E.g., kinetic energy and potential energy of an object
Define Microscopic form of energy and give examples
Related to the molecular structure or molecular activity of the system. The sum of all the microscopic forms of energy is call internal energy
Define total kinetic energy (macroscopic)
the energy that a system possesses as a result of its motion relative to some reference frame
What does adiabatic mean?
No heat transfer
What two functions are dependent of the PATH followed
Heat & Work
What functions are dependent on the state (Point functions)
Properties (P, T, v, u)
What is the most common form of mechanical work in thermo?
Boundary Work
What are the two requirements for a work interaction between a system and its surroundings?
- Must be a FORCE acting on boundary.
2. Boundary must MOVE
Define Pure substance
Has a homogeneous chemical composition and may exist in more than one phase (mixture of elements, mixture of two or more phases)
Examples of a Pure Substance
- Mixtures of gases, such as air
- Water
- Carbon Dioxide
- Nitrogen
What are the 5 phase-change processes of pure substances
- Compressed liquid
- Saturated liquid
- Saturated liquid-vapor mixture
- Saturated vapor
- Superheated vapor
Define Saturation Temperature
Temperature at which a pure substance changes phase at a given pressure
