7- 97.20 (a) ±.±HTH=°−10425Cin kJ kgbg±..Hout9.36 kJ kg=−=104 340 25±.Hin5kJ kg=104 300 2520Δ±...H=−=9 3652016 4kJkgΔΔΔ²²²²²HEEQWkps++=−assumedno moving parts²EkEpWs===00ch²±QHnH1.25 kWkg1 kJ / s 10 g1 mol4.16 kJkW1 kg28.02 gmol s3⇒===²²².nQHΔ10 7= 10.7 mol22.4 L STP303 KkPasmol273 K110 kPaL/sL s⇒²..V10132455246(b) Some heat is lost to the surroundings, some heat is needed to heat the coil, enthalpy is assumed to depend linearly on temperature and to be independent of pressure, errors in measured temperature and in wattmeter reading. 7.21 (a) ±±±.±.±HaTbaHHTTbH aT=+=−−=−−==−=−UV|W|°−2111129 825850305252 30130 21302bgkJ kgC±..=⇒== °025refC Table B.1 ⇒==×−SGV.±.CH l33614m659 kgmk
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This note was uploaded on 02/27/2012 for the course CHEMICAL E 312 taught by Professor Cheung during the Fall '11 term at The University of Akron.