Sample Final Exam Chapters 6 and 19

# Sample Final Exam Chapters 6 and 19 - Æ 6CO 2 g 3H 2 O l 4...

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Department of Chemistry CHM 1220/1225 Final Exam – Sample Exam – Chapters 6 and 19 1. How many grams of F 2 must react with NaCl in the following reaction to give 800. kJ of energy? [Molar masses: NaCl = 58.443 g; F 2 = 27.996 g; NaF = 41.988 g; Cl 2 = 70.906 g Is the energy (circle one) RELEASED or ABSORBED? 2 NaCl + F 2 ± 2 NaF + Cl 2 ; Δ H = -320 kJ 2. As a reaction proceeds in a cylinder equipped with a movable piston, 350 J of heat is released and the volume of the cylinder changes from 1.20 to 20.36 L. The pressure in the cylinder is 1.00 atm and the temperature is 298 K. What is the change in total internal energy for the reaction? Report your answer in kJ. 3. A 3.51 g sample of benzene, C 6 H 6 , was burned in excess oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00°C to 37.18°C. If the heat capacity of the calorimeter and its contents is 12.05 kJ/°C, what is the value of q for the burning of one mole of benzene at constant volume and 25.00°C? The reaction is C 6 H 6 ( l ) + 15 / 2 O 2 ( g
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Unformatted text preview: ) Æ 6CO 2 ( g ) + 3H 2 O( l ) 4. Given the following data for the reaction: 3 Cl 2 ( g ) + 2 CH 4 ( g ) ± CH 3 Cl( g ) + CH 2 Cl 2 ( g ) + 3 HCl( g ) H f ° (kJ/mol) 0.00 -74.81 -80.83 -92.47 -92.31 S° (J mol- 1 K-1 ) 223.1 186.3 234.6 270.2 186.9 a. What is Δ H o for the reaction? b. What is Δ S o for the reaction? c. Using Δ H o and Δ S o , find Δ G , Is the reaction spontaneous ( circle one ) YES NO IT IS AT EQUILIBRIUM d. What is Δ G at 400 o C. 5. Calculate K at 25°C for sulfurous acid: H 2 SO 3 ( aq ) <==> H + ( aq ) + HSO 3-( aq ) Δ H f ° (kJ/mol) -608.8 0 -626.2 S ° (J/mol K) 232.2 0 139.8 Which thermodynamic factor is the most significant in accounting for the fact that sulfurous acid is a weak acid? 6. Identify all the sign combinations of D H and D S that are possible for a process carried out at constant temperature and pressure. Determine whether each possibility is spontaneous, nonspontaneous, or whether both situations are possible. Explain....
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## This note was uploaded on 09/30/2011 for the course CHEM 1220 taught by Professor Barber during the Spring '08 term at Wayne State University.

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