- "" $"&""$& Chemistry 114 General College Chemistry II" Instructor Dr Gregory Jursich Email [email protected] BioE

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Unformatted text preview: ! "# * " ' $% " & ( ) " ' ' "$'& Chemistry 114 General College Chemistry II ! " ! Instructor: Dr. Gregory Jursich Email: [email protected] BioE Office: 233 SEO Office: Phone: 312-413-8641 Office: 3235 SEL Office Phone: 312-996-3178 Lab: 1215 SEL Lab Phone: 312-996-8373 Office Hours: MWF 12:00 12:45 pm and 2:15-2:45 pm or by appointment + ' need to define system: +q , For Quantitative Study of Energy in Chemistry -q +w (PV) "system" contracts -w (PV) "system" expands - ' $' ' For Quantitative Study of Energy in Chemistry +q qp +w (PV) "system" contracts -w (PV) "system" expands -q qp -> effective heat gain/loss at constant pressure - ' $' ' Heat Capacity: Cp = q/T Note: if q > 0 obviously T > 0 so Cp must always be > 0 cs = CP/m cP = CP/n ' ' No heat flow between "system" & "surroundings" but internal parts absorb or release a little heat, q. q = Ccalorimeter T Sum of all q `s = 0 mix hot + cold water in calorimeter qhot + qcold + qcal = 0 ' ' . / 0 Sum of all q `s = 0 & mix hot + cold water in calorimeter qhot + qcold + qcal = 0 qcold + qcal = -qhot (mcsT)cold + (CT)calorimeter = -(mcsT)hot $ " 1 & $' ' 2$ %& ' ) !23 ) ' ( 4 ' " $' ' #$ '+' " + '+' 5 #$ ( + ' +' ' + " $ 6 $ #$ ( H Enthalpy is a "state" property independent of path heat, q, depends on path just like distance State properties of "system" 3' ' . $ ' ' 7 $ $ Independent of how it gets there. Change in prop. depends only on initial & final states State properties of "system" &) * #$ ( H + ) ) change of energy under constant pressure conditions (ie., PV work is built into it) " 8 Reactions: $ Hr = Hproducts Hreactants Phase Changes: solid liquid Hmelting = Hliq - Hsolid liquid gas Hvaporization = Hgas - Hliq Changes in Enthalpy: Reactions at constant pressure... Reactions: Hr = Hproducts Hreactants Exothermic Rxn: heat is released from "chemical system" (qP <0) H < 0 Hproducts < Hreactants Changes in Enthalpy: Reactions at constant pressure... Reactions: Hr = Hproducts Hreactants Endothermic Rxn: heat is absorbed into "chemical system" (qP>0) H > 0 Hproducts > Hreactants Changes in Enthalpy: Reactions at constant pressure... Reactions: , , ./ , 01 , 34 4 5 ) Hr = Hproducts Hreactants . / /& H > or < 0 ?? 4 4 - & ) 4 4 23 * 1 $ Changes in Enthalpy: Reactions at constant pressure... Reactions: , , ./ & , . 01 , / ) Hr = Hproducts Hreactants /& - 3 ) moles of products double? H of reaction doubles? 6 ! & * & & CO(g) + O2(g) 2 CO(g) + O2(g) CO2(g) Hr = -283 kJ/mol 2 CO2(g) Hr = -566.0 kJ/mol Changes in Enthalpy: Reactions at constant pressure... Reactions: 6 ! & & * Hr = Hproducts Hreactants & CO2(g) Hr = -283 kJ/mol 2 CO2(g) Hr = -566.0 kJ/mol CO(g) + O2(g) 2 CO(g) + O2(g) 7 8 4 Hr (forward) = - Hr (reverse) Changes in Enthalpy: Phase Change at constant pressure... Melting: (requires heat; qP >0) "Molar Enthalpy of Fusion" Hfus = Hliquid Hsolid Vaporizing: (requires heat; qP >0) "Molar Enthalpy of Vaporization" Hvap=Hvap-Hliq Changes in Enthalpy: Phase Change at constant pressure... Intermolecular Forces vs H Temperature Changes from Heating a Substance at Constant Pressure Solid -> Liquid -> Gas (A-B) (D-F) (H-J) TBP Hvap TMP Hfus 9 3'& :* 6 & - ) ) * * " 8 0* ; ) ) * * & & ( 9 :, 3 ( 0 ><, 3 ( 3; " , 9: = ) # ( 3? " , : = 8* 9 :, ( ; 3 " 3 <9 = 0 ><, ( 9<" 3 3 = ) # 0* ) ) 0? 3:,3 ; @ & * * ; 3:,3 >; && & # 4 #$ 0? 3:, 01 9 : / 8 * / #$ 9 :, 01 ; 3:, ; 3 , 3 >; 9 :, 0 0? 3:, / 3 ; / 8* , ; 3:,0 9 :, >; 3 >< 3: * ) (39.70 g)(2.280 J/g-C)(121.5 C) + (39.70g)(357.6 J/g) + (39.70g)(1.650J/gC)(23.3 C) 26.73 kJ ...
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This note was uploaded on 04/07/2008 for the course CHEM 114 taught by Professor Jursich during the Spring '08 term at Ill. Chicago.

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