This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: CHEM 188 Spring, 2008 Hour Exam 3 (Green) April 10, 2008 Instructions: Your scantron answer sheet must show your NAME , 7-DIGIT KU ID NUMBER , and LAB SECTION . (Begin these entries at the LEFT end of the space provided.) In answering the questions, be careful to fill in the corresponding circles on the answer sheet according to the number of the question on the exam. USE A SOFT (No. 2) PENCIL . Note that a periodic table of the elements is attached at the end of the exam. Useful information: Gas constant R = 8.314 J K- 1 mol- 1 = 0.0821 L atm K- 1 mol- 1 Boltzmann constant k = 1.38 10- 23 J K- 1 Conversion factor: 1 L atm = 101.3 J 1. An ideal gas is allowed to expand at constant temperature from a volume of 1.00 L to 5.00 L against a constant external pressure of 2.00 atm. What is the value of w , the work done on the gas? A. -810 J B. 8.00 J C. 0 J D. +8.00 J E. +810 J 2. Calculate w , the work done on the system, when 40.0 g of potassium reacts with water to form hydrogen gas at 2.00 atm and 40 o C. (Assume ideal gas behavior.) 2K( s ) + H 2 O( l ) 2KOH( aq ) + H 2 ( g ) A. 0.333 kJ B. 0.666 kJ C. 1.33 kJ D. 2.66 kJ E. none of these 3. A gas is compressed, during which 400 J of P-V work is done on the gas. At the same time, it absorbs 150 J of heat from the surroundings. What is the change, E , in the internal energy of the gas? A. 550 J B. 250 J C. 0 J D. 250 J E. 550 J 4. Given the thermochemical equation N 2 ( g ) + 3H 2 ( g ) 2NH 3 ( g ) + 92.6 kJ calculate the enthalpy change, H , for the reaction NH 3 ( g ) 1/2 N 2 ( g ) + 3/2 H 2 ( g ) A. 92.6 kJ B. 46.3 kJ C. 0 kJ D. 46.3 kJ E. 92.6 kJ 1 5. The molar enthalpy of fusion (melting), H fus , for water is 6.01 kJ/mol. , for water is 6....
View Full Document
- Spring '08