Basic concepts Flashcards
1st Law of Thermodynamics
Conservation of energy
Energy cannot be created nor destroyed
2nd Law of Thermodynamics
Heat/energy moves from a source of high concentration to a source of cold concentration
Classical Thermodynamics
Macroscopic approach
Statistical Thermodynamics
Microscopic approach
Fundamental Dynamics
Mass
Length
Time
Temperature
Electrical current
Amount of light
Amount of matter
Secondary/derived dimensions
Velocity
Energy
Volume
Unity Conversion Ratio
(N ) / (kg * (m/s^2)) = 1
1 lbf) / (32.174 lbm * (ft/s^2)
System
Quantity of matter or a region in space chosen for study
Closed System
Heat and work interaction
Mass is constant
Energy can enter and leave the system
Open System
Mass is changing
Volume is constant
Involves heat, work, and mass interaction
Energy can enter and leave the system
Specific Volume
v = V / m
Specific Total Energy
e=E / m
Specific gravity
Relative density
SG = density / density of h20 at 4degrees Celcius
Properties of a system
Pressure
Temperature
Volume
Mass
Intensive Properties
Independent of the mass of a system
Extensive Properties
Dependent on the mass of a system
State of a system
Described by a set of properties
Equilibrium
State of balance
Thermal Equilibrium
Temperature is the same throughout the system
Practically speaking, not possible to reach complete thermal equilibrium
Mechanical Equilibrium
No change in pressure
Chemical Equilibrium
No chemical reactions
Phase Equilibrium
Entire phase of the system is the same
Gas=gas
Liquid = liquid
State Postulate
The state of a simple compressible system is completely specified by two independent intensive properties.
Simple Compressible System
Absence of electrical, magnetic, gravitational, motion, and surface tension effect
