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Unformatted text preview: Chem. 1B White Version Final 2005 1 1. Using the following data: G f o (kJ /mol) N 2 H 4 ( l ) 149 N O 2 (g) 52 H 2 O ( l ) 237 O 2 (g) 0 a) (6 pts) Calculate G o for the following reaction at 298 K: N 2 H 4 ( l ) + 3 O 2 (g) 2 NO 2 (g) + 2 H 2 O ( l ). b) (6 pts) Predict the sign of S and H. Circle the answer. S < 0 S > 0 S = 0 H < 0 H > 0 H = 0 c) (3 pts) Will the reaction be more spontaneous at higher or lower temperature? Circle the answer. Higher T Lower T 2. (8 pts) The standard enthalpy of combustion of 1 mol of ethanol, CH 3 CH 2 OH ( l ), is 1368 kJ at 298 K. Given the following enthalpies of formation, calculate H f o for CH 3 CH 2 OH ( l ). H f o (kJ /mol) H 2 O (l) 286 C O 2 (g) 394 3. (6 pts) Write the reactions that correspond to the following enthalpy changes: a) H f o for solid iron(III)oxide. b) H f o for calcium carbonate, CaCO 3 . Chem. 1B White Version Final 2005 2 4. (4 pts) Write the electronic configuration and indicate the number of unpaired electrons for each of the following species. electronic configuration number of unpaired electrons a) S b) Se 5. a) (6 pts) Draw the Lewis structures, all three resonance forms, for the cyanate ion, NCO , assign formal charges to all atoms. Carbon is the central atom....
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