Chem 177 Final Exam: Thursday, May 12 2 PM Same rooms as previous exams

Transcription

1 Dr. Joe Burnett Spring 2010 This exam consists of 24 questions on 9 pages Chem 177 Exam III April 5, 2010 Name Recitation TA Recitation Section Grading Teaching Assistants and Recitation Sections Page Points Score Name Sections Time Stacey Althaus 5 10: pts 16 pts 24 pts Kyle Marchuk Kristopher McKee Justin Smith Anthony Stender 1, 10 11, , 3 8:00, 1:10 2:10, 1:10 12:10 8:00, 9: pts 22 pts Nishad Thamban Chandrika Songchen Xu 4, 6 7, 9 9:00, 11:00 11:00, 12:10 7 TOTAL 14 pts 104 pts Questions are written on both sides of each page. There is a periodic table and an equation on the last page. You may remove this page for scratch paper. Show all work. Answers should include appropriate units and contain the correct number of significant figures. Chem 177 Final Exam: Thursday, May 12 2 PM Same rooms as previous exams

2 1. (6 pts) Consider the following spheres. Indicate which sphere represents Na +, K, and K (2 pts) On the sketch of the periodic table below that shows only the main group (representative) elements, draw an arrow from the element with the largest radius to the smallest radius. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Ga Ge As Se Br Kr Rb Sr In Sn Sb Te I Xe Cs Ba Tl Pb Bi Po At Rn 3. (2 pts) On the sketch of the periodic table below that shows only the main group (representative) elements, draw an arrow from the element with the largest first ionization energy to the element with the smallest first ionization energy. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Ga Ge As Se Br Kr Rb Sr In Sn Sb Te I Xe Cs Ba Tl Pb Bi Po At Rn 4. (4 pts) Which one of the following electron configurations represents an excited state? a) 1s 2 2s 1 2p 3 b) 1s 2 2s 2 2p 3 c) 1s 2 2s 2 2p 5 d) 1s 2 2s 2 2p 6 3s 2 e) all of the above are excited state electron configurations f) none of the configurations represent an excited state 5. (2 pts) What is the name of the family/group on the periodic table that contains Be, Mg, Ca, and Sr?

3 3 6. (10 pts) Calculate the enthalpy change ΔH o in kilojoules for the following reaction representing the formation of glucose from water and carbon dioxide (photosynthesis). For full credit, show all work, use units, and report your answer to the correct number of significant figures. 6 CO 2 (g) + 6 H 2 O(l) C 6 H 12 O 6 (s) + 6 O 2 (g) answer: kj 7. (6 pts) Calculate ΔH for the reaction 2 C(s) + O 2 (g) 2 CO(g) given the following chemical equations and their respective enthalpy changes: C(s) + O 2 (g) CO 2 (g) ΔH = kj CO(g) O 2(g) CO 2 (g) ΔH = kj answer: kj

4 8. (8 pts) What is energy in Joules of one photon of yellow light with a wavelength of 589 nm? For full credit, show all work, use units, and report your answer to the correct number of significant figures. 4 answer: kj 9. (4 pts) Identify whether the following bonds are polar covalent, nonpolar covalent, or ionic. For polar covalent bonds, indicate the direction of the dipole moment using formalism. bond nonpolar covalent, polar covalent, or ionic? Cl As Na F 10. Complete and balance the following reaction equations. For credit, you must show phases correctly. A. (4 pts) K(s) + H 2 O(l) B. (4 pts) CaO(s) + H 2 O(l) C. (4 pts) NaOH(aq) + SO 2 (g)

5 5 11. Consider the following set of quantum numbers: n = 3, l = 2, m l = 2, m s = A. (2 pts) What orbital does this set of quantum numbers correspond to? a) 2p b) 3s c) 3p d) 3d e) 3f B. (2 pts) How many electrons in a single atom can have this set of quantum numbers? a) 1 b) 2 c) 3 d) 4 e) unlimited C. (2 pts) Which quantum number indicates the orientation of the orbital? a) n b) l c) m l d) m s e) none of them D. (2 pts) Write the quantum number for another electron in the same orbital. n l m l m s 12. (4 pts) Which of the following is the electron configuration of the Fe 2+ ion? a) 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 4s 2 b) 1s 2 2s 2 2p 6 3s 2 3p 6 3d 4 4s 2 c) 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 d) 1s 2 2s 2 2p 6 3s 2 3p 6 3d 8 4s 2 e) none of the above

6 13. (2 pts) How many radial nodes are in a 3s orbital? (2 pts) Which of the following ions is isoelectronic with Ne? a) O 2 b) F c) Na + d) Mg 2+ e) all are isoelectronic with Ne 15. (2 pts) Which of the following ions has the smallest diameter? a) O 2 b) F c) Na + d) Mg 2+ e) all have the same diameter 16. (4 pts) Write the full electron configuration of a ground-state vanadium atom. 17. (4 pts) Write the condensed electron configuration of a ground-state vanadium atom. 18. (2 pts) Is vanadium diamagnetic? 19. (2 pts) How many valence electrons does vanadium have? 20. (4 pts) Which of the following metals reacts most vigorously with water? a) Li b) Be c) Cs d) Ba

7 21. (4 pts) Write the correct ordering of the first ionization energy from smallest to largest for sodium, magnesium, silicon, and aluminum: Na, Mg, Si, Al (4 pts) Consider the plot of the ionization energies for multiple ionizations of an atom in the third period. What is the element? a) Na b) Mg c) Al d) Si e) P f) S 23. (2 pts) Exothermic processes are thermodynamically favored. For an endothermic process to be spontaneous (to occur on its own), what must occur (or what must be true)? 24. (4 pts) Draw the Lewis Dot structure of CO 2.

8 8 Chem 177 Periodic Table Exam III

9 9 density of water: 1.00 g/ml 1 cal = joules c = 3.00 x 10 cm 10 s or 3.00 x 10 m 8 s h is 6.63 x joule sec 1 λ = R H 1 n n n 2 > n 1 2 R H = x 10 7 m 1 µ = Q r 3.34 x C-m = 1 Debye electronic charge: e = C E n = J 1 Δx Δmv h 4 π n 2