Chemical Engineering Thermodynamics
Thermodynamics is the science of relationship between heat work and the properties of the system involved.
Terms to acknowledge
[edit | edit source]- Process - changes that a system undergoes from one equilibrium state to another
- Cyclic Process - process which returns the system to the initial value at completion
- Isothermal Process - change in system at constant temperature. It is often necessary to exchange heat with surroundings to maintain constant temperature.
- Isobaric Process - change in system at constant pressure
- Isochoric (Isometric) Process - change in system at constant volume
- Adiabatic Process - process in system without heat exchange with surrounding. Q=0
Thermo variables
[edit | edit source]1. State variables - macroscopic quantities defining condition of a system such as temperature, pressure, mass
2. Path variables - value of path taken by the system between 2 state such as heat and work
Work (W)
- the energy transferred associated with a force acting through a distance: dW = F. dL
- also called the PdV work when above equation is integrated.
- enable us to find work associated with expansion or compression of a path
[ Sign of convention depends on authors, some uses +W when work is done by system on surroundings and -W when work is done on system by surroundings while others versa-wise; in this chapter, the former is used.]
Heat (Q)
- energy type which is transferred due to a temperature difference
- exchange in system and surroundings which would result in temperature or phase change.
Sign of convention: +Q when heat is added into the system ; -Q when heat is removed from the system