Thermodynamics Flashcards
Adiabatic process
no energy crosses system boundary
Isentropic process
reversible Adiabatic process. No entropy production.
throttling process
adiabatic process with pressure drop and constant enthalpy
Isobaric process
constant pressure process
isochoric or isometric
constant vol process
quasiequilibrium or quasistatic process
process that can be divided into discrete equilibrium states
work done by the system on the surroundings
+ve work
Work done by the environment on the system
-ve work
Heat sign conventions
Heat added to system +ve
Heat lost to surroundings -ve
Reversible boundary work for a closed system
area under P-V curve, integral of P.dV
-ve boundary work
indicates decrease in volume
const volume process, close thermodynamic system
Guy-Lussac’s law
Open thermodynamic system
working fluid crosses system boundary
___________\ can be used to estimate vapor pressures for pure solids and liquids
Clausius clapeyron equation
Dry bulb temp
Temp measured by thermometer exposed to air
Wet bulb temp
temp of air that has gone through adiabatic saturation. measured by thermometer covered with water-saturated cotton wick
Dew-point temp
when moist air is cooled at const pressure process, water condenses at this temp
unsaturated air
mixture of water vapor and superheated steam. Dew point temp < Wet bulb temp
Kelvin-planck statement of 2nd law
no heat engine can operate in a cycle transferring heat with a single reservoir.
Corollary to kelvin planck 2nd law of TD
no heat engine can operate with higher eff than a Carnot engine
Clausius statement of 2nd law of TD
no refrigeration or heat pump can operate without a net work input
Corollary to Clausius statement
no refrigeration or heat pump operate with higher COP than a Carnot heat pump or refrig
Specific properties (u,v,h,s..) are ____ weighted
gravimetrically (Mass or weight)
Molar properites are ____ weighted
volumetrically
Gibbs free energy
Energy required for a reaction to occur.
-ve value indicates spontaneous reaction
Change in gibbs energy
can be used to find exergy without KE and PE terms
Max useful work from an open system at const pr and temp
Helmholtz Free Energy
Max work obtainable from a closed system at const vol and temp
