090311_Exam2_answer - Chem340 Physical Chemistry for Biochemists Exam 2 Mar 6 2009 Your Name I affirm that I have never given nor received aid on

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chem340 Physical Chemistry for Biochemists Exam 2 Mar 6, 2009 Your Name _ I affirm that I have never given nor received aid on this examination. I understand that cheating in the exam will result in a grade F for the class. Signature . Sec 1 Multiple Choice [ /39] Sec 2 Calculation/MC [ /20] Sec 3 Long Question [ /45] Sec 4 Derivation [ /11] Total [ /100] Total points are 115 points. If you score more than 100, you will receive 100 points.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Multiple Choice Questions (Some questions may be similar to those one in quiz, but not the same) Each 3 points [ /39] Q1. Calculate Δ S if the temperature of 1 mol of an ideal gas with C P,m = 5/2 R is decreased from 350 K to 150 K under conditions of constant volume . Choose the correct formula. (a) ) / ln( K K R 350 150 2 3 (b) ) / ln( K K R 350 150 2 (c) ) / ln( K K R 350 150 2 5 (d) ) / ln( K K R 150 350 2 3 (e) ) / ln( K K R 150 350 2 (f) ln 2 5 R (350K/150K) Q2. Which relationship is correct for an irreversible process? Choose all correct answer(s). (a) > T Dq le irreversib 0 (b) 0 > dS (c) < T Dq dS le irreversib (d) T Dq dS le irreversib > (e) 0 < dS (f) > T Dq dS le irreversib Q3. One mole of an ideal gas with C P = 5R/2 undergoes the transformations from an initial state described by T i = 300. K and P i = 0.50 bar. The gas undergoes a reversible isothermal compression at 300 K until P becomes 1.0 bar. Choose a formula that best represents Δ S . (a) Δ S = (5R/2)ln(0.5/1) (b) Δ S = (5R/2)ln(1/0.5) (c) Δ S = Rln(0.5/1) (d) Δ S = Rln(1/0.5) Q4. Can this process happen spontaneously? (a) Yes (b) No (c) This process should be in equilibrium (d) I have no idea. Q5. Consider the formation of glucose from carbon dioxide and water, that is, the reaction of the following photosynthetic process: 6CO 2 ( g ) + 6H 2 O( l ) C 6 H 12 O 6 ( s ) + 6O 2 ( g ). Choose a formula that best represents the reaction entropy for this chemical system at T = 348 K . The following table of information will be useful in working this problem: (a) 50x (-6x 213.8 -6x 70 + 209.2 + 6x 205.2) + (-6x 37.1 -6x 75.3 + 219.2 + 6x 29.4) Jmol -1 K -1 (b) (-6x 213.8 -6x 70 + 209.2 + 6x 205.2) + 50x (-6x 37.1 -6x 75.3 + 219.2 + 6x 29.4) Jmol -1 K -1 (c) (-6x 213.8 -6x 70 + 209.2 + 6x 205.2)ln(348/298) + (-6x 37.1 -6x 75.3 + 219.2 + 6x 29.4) Jmol -1 K -1 (d) (-6x 213.8 -6x 70 + 209.2 + 6x 205.2) + (-6x 37.1 -6x 75.3 + 219.2 + 6x 29.4)ln(348/298) Jmol -1 K -1 (e) None of them Q6. Which formula represents the reaction enthalpy at 298 K for the reaction in Q5 in kJmol -1 units? (a) (-393.5 - 285.8 - 1273.1) (b) (6x 393.5 + 6x 285.8 - 1273.1) (c) (-6x 393.5 - 6x 285.8 + 1273.1) (d) (-393.5 - 285.8 - 1273.1)
Background image of page 2
3 Q7. What is the actual reaction that one can use to calculate the reaction enthalpy for the following reaction? 2NaOH( aq ) + H 2 SO 4 ( aq ) Na 2 SO 4 ( aq ) + 2H 2 O( l ). Choose the most appropriate reaction. Assume complete dissociation of NaOH, H 2 SO 4 , and Na 2 SO 4 . (a) 2OH - ( aq ) + 2H + ( aq ) 2H 2 O( l ) (b) OH - ( aq ) + H + ( aq ) H 2 O( l ) (c) 2Na + ( aq ) + SO 4 2+ ( aq ) Æ NaSO 4 (aq) (d) Na + ( aq ) + ½ SO 4 2+ ( aq ) Æ ½ NaSO 4 (aq) Q8. How much is { Δ U reaction 0 - Δ H reaction 0 } for the reaction in Q7? Assume that the temperature is T =298K. The unit is Jmol -1 . a. -2nRT b. -nRT c. 0 d. nRT e. 2nRT Q9. Choose the most appropriate reaction for which a standard formation enthalpy for NH 3 can be obtained as a reaction enthalpy.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/14/2010 for the course CHEM 340 taught by Professor Yoshitakaishii during the Spring '07 term at University of Illinois, Urbana Champaign.

Page1 / 10

090311_Exam2_answer - Chem340 Physical Chemistry for Biochemists Exam 2 Mar 6 2009 Your Name I affirm that I have never given nor received aid on

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online