Chemistry - Thermodynamics - I Question with Solution | TestHub
ChemistryThermodynamics - IIsothermal Process/Isobaric/IsochoricHard2 minQB
ChemistryHardsingle choice
n moles of an ideal gas at 8 atm expand isothermally at temperature T to a final pressure of 2 atm in three steps. In every step a constant external pressure exactly 2 atm below the pressure at the start of that step is maintained until the gas reaches that pressure. The work w done on the gas in the whole process is
Options:
Answer:
C
Solution:
The steps are 8 to 6 atm (Pext = 6), 6 to 4 atm (Pext = 4) and 4 to 2 atm (Pext = 2). For a step, w = -Pext nRT(1/(Pf) - 1/(Pi)). Step 1: -6(1/6 - 1/8) = -0.250. Step 2: -4(1/4 - 1/6) = -0.333. Step 3: -2(1/2 - 1/4) = -0.500. Total = -13/12nRT = -1.083 nRT. (The reversible value -nRTln 4 = -1.386 nRT is larger in magnitude.) Matches (c).
Stream:JEESubject:ChemistryTopic:Thermodynamics - ISubtopic:Isothermal Process/Isobaric/Isochoric
⏱ 2mℹ️ Source: QB
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