Download Exam 1 reference sheet and more Cheat Sheet Chemical Thermodynamics in PDF only on Docsity! Solving Thermodynamics Problems Set states Energy/Enthalpy 1. Closed system โ internal energy (u) 2. Control volume โ enthalpy (h) Substance 1. Water โ use tables a)Saturation (Table A-2 or A-3) โ pressure/temperature and 1 other property set state u=uy + xX(Uy โ Uy) b)Superheated vapor (Table A-4) โ any 2 properties set the state Ug Uy T โT, Rone - u=uyt+ co) Liquid (1) High pressure โ compressed liquid (Table A- 5) using any 2 properties (2) Low pressure โ approximate as saturated liquid at temperature 2. R-22, R-134a, ammonia, or propane โ use tables a)Saturation โ pressure/temperature and 1 other property set state b)Superheated vapor โ any 2 properties set the state c) Liquid โ approximate as saturated liquid at temperature 3. Air a)Energy/enthalpy found in Table A-22 using temperature b)Ideal gas model relates pressure, volume and temperature pu (1) Polytropic process: pv" = constant (constant p > n=0, constant v > n =e, constant T > n= 1) Te (a e T \py Ve 4. Carbon dioxide, carbon monoxide, oxygen, or nitrogen โ use tables a)Energy/enthalpy found in Table A-23 using temperature Sle b)Ideal gas model relates pressure, volume and temperature (1) Polytropic process: pv" = constant (constant p > n=0, constant v > n =e, constant T > n= 1) 5. Helium, neon, or argon โ constant specific heat (Cp = 2.5 Rand w= 1.5 R, k= G/cy) a)Change in energy/enthalpy found from specific heat and temperature Uz โ Wy = Cy(T2 โ T1) hy -hy = Cp (T2 โT,) b)Ideal gas model relates pressure, volume and temperature (1) Polytropic process: pv" = constant (constant p > n=0, constant v > n =e, constant T > n= 1) 6. Other โuse specific heat (Tables A-19, A-20, and A-21) Isentropic processes 1. Water, R-22, R-134a, ammonia, or propane โ use tables S1 = S2 2. Airโuse Table A-22 Bz _ Piz Ya _ Me Pr Pri V1 Ura 3. Carbon dioxide, carbon monoxide, oxygen, or nitrogen โ use Table A-23 0=s,โs,=s9โs?โRin2 Pi 4. Helium, neon, or argon โ constant specific heat (k = Cp/cy) Tp _ eer" _ cy" T, Py V2. 5. Isentropic efficiencies a)Turbine tithe 1 Tatas b)Compressor/Pump _ lias = hy Ne Ty hy c) Nozzle _ve/2 VER
