Intro Flashcards
Define Thermodynamics
Study on effect of heat and work when a system is compressed, heated or cooled
Thermodynamic Properties
- Continuum model
- P,T,V and m
- mostly fluid
- Microscopic level
Thermodynamics 3 properties
Intensive properties - independent of mass of system such as T, P and ρ
Extensive properties - depends on size or extent of the system (V, m, l, size, enthalpy and u)
Specific properties - “per unit mass”
Define Work, Energy and Power
Work (J) - force times distance
Energy (J) - ability to do work
Power (W) - rate of doing work
Thermodynamics system
Got physical or virtual boundary. Area within space where behaviour of fluid is studied whether compressed, expanded, cooled or heated
Type of system
Open - mass can leave boundary
Closed - no mass can leave.
Both allow heat and work move across system
Isolated - no mass, heat and work
Thermodynamics State of a system
Thermal equilibrium - T same throughout system
Mechanical equilibrium - no change in P
Phase equilibrium - mass of each phase reach an equilibrium level and stays there
Chemical equilibrium - chemical comp does not change with time (no chem reaction)
How to determine state of system
Need to know at least 2 fluid prop:
1. P and T
2. P and spec V
3. Enthalpy and entropy
4. Any combo
Thermo process
Change one equilibrium to another
Quasi - equilibrium
Slow process allow equal changes of properties
Thermodynamics cycle
Process in which it start with one state and end with the same state
Zeroth law of thermodynamics
2 body are in thermal equilibrium if same temp even if they are not in contact
State the ideal gas equation
PV= nRT
State the gas constant
R = 8.314/ mol
