Chemistry 331 Quiz 3: Ideal Gas Expansion and Adiabatic Processes - Prof. Stefan Franzen, Quizzes of Physical Chemistry

Download Chemistry 331 Quiz 3: Ideal Gas Expansion and Adiabatic Processes - Prof. Stefan Franzen and more Quizzes Physical Chemistry in PDF only on Docsity! Quiz #3 Week: Sept. 27 -Sept. 29 Name _________________________ Chemistry 331 Equations and constants: R = 8.31 J/mol-K = 0.08206 L-atm/mol-K δw = – PdV , dU = δw , CV = 32nR , CP = 5 2nR 1. A. What is the work of expansion for an ideal gas from 10 L to 100 L against a constant pressure of 1 atm? w = -P∆V = - (1 atm)(100L – 10L) = -90 L-atm w = -90 L-atm * 1e-3 m3/ dm3 * 1.01325e5 Pa/ atm = 9119.25 Pa * m3 = -9119 J Answer in L-atm = ________________________________. Anser in Joules = ________________________________. B. How many moles of gas are there in the expansion in part A? P1V1 = P2V2 = nRT n = PV/RT = (10 atm * 10 L) / (.08206 L-atm/mol-K * 298K) n = 4.09 moles Moles of gas = __________________________________. C. What is the initial pressure in part A? P1V1 = P2V2 P1 (10 L) = (1 atm)(100 L) P1 = 10 atm Pressure = ___________________________________. 2. In an adiabatic expansion a monatomic ideal gas cools from 300 K to 270 K. Determine the work of expansion. dw = Cv*dT w = 3/2*n*R*(T2 – T1) w = 3/2 * 4.09 * 8.314 J/mol-K * (270K – 300K) w = -1530 J Work = ____________________________________.