1Homework 3 Answer (Due 02/04/2011 Friday) P2.3, P2.7, P2.8, P2.11, P2.16, P2.19, P2.20, P2.21, P2.23, P2.25, P2.26 P2.3)3.00 moles of an ideal gas are compressed isothermally from 60.0 to 20.0 L using a constant external pressure of 5.00 atm. Calculate q,w,U,and H. The work against a constant pressure: J1003.2m1060m1020Pa1013255Vpw43333external0Uand 0Hsince 0Tand PVUHJ1003.2wq4P2.7)For 1.00 mol of an ideal gas, Pexternal= P= 200.0 103Pa. The temperature is changed from 100.0°C to 25.0°C, and CV,m= 3/2R.Calculate q, w,U,and H. J935K373-K982molKJ314472.8mol.0123TCn U1-1-mV,J5591K373-K982molKJ314472.8mol.0125TRCn TCn H1-1-mV,mp,JH1559qPJ624)1559()935(q-UPJJwP2.11)Calculate Hand Ufor the transformation of 1.00 mol of an ideal gas from 27.0°C and 1.00 atm to 327°C and 17.0 atm if CP,m20.90.042TKin units of J K1 mol1For an ideal gas, H is given by:
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2K600K300TTmp,dTKT0.04220.9n dTCn ΔHfiJ1011.94J10675.J106.27JT0.021JK300K60020.9ΔH333K600K3002J109.45K300KmolJ8.314472mol1J1094.11ΔTRn ΔHpVΔΔHΔU31-1-3P2.12)Calculate wfor the adiabatic expansion of 1.00 mol of an ideal gas at an initial pressure of 2.00 bar from an initial temperature of 450. K to a final temperature of 300. K. Write an expression for the work done in the isothermal reversible expansion of the gas at 300. K from an initial pressure of 2.00 bar. What value of the final pressure would give the same value of was the first part of this problem? Assume that CP,m= 5/2R. J101.87K501molKJ314472.8mol23TRCn Uw31-1-mp,adpplnTRn wfireversibleand TRn wpplnreversiblefi7497.0K003molKJ314472.8mol1J101.87TRn wppln1-1-3reversiblefi12.2ppfiifp p0.9442.12barP2.15)An ideal gas undergoes an expansion from the initial state described by Pi,Vi,Tto a final state described by Pf,Vf,Tin (a) a process at the constant external pressure Pfand (b) in a reversible process. Derive expressions for the largest mass that can be lifted through a height hin the surroundings in these processes.