Dr. Rick Fletcher. Exam 3 Chemistry 101 March 28, Clearly print your name in the name section of the Scantron answer sheet.

Transcription

1 Name: Dr. Rick Fletcher Exam 3 Chemistry 101 March 28, 2010 Clearly print your name in the name section of the Scantron answer sheet. Clearly place your student ID number in the SUBJECT section of the Scantron sheet. Maintain appropriate security over your exam. Do not let others see your answers. There is only one most correct response to each of the multiple choice questions. Choose the best answer. Each of the twenty-five questions is worth 4 points. Since the Scantron sheets will not be returned to you, please work through the entire exam and circle the best answer on this exam. Mark this exam as you work the problems then transfer the responses to the Scantron sheet all at one time. This is the best way to reduce errors. Use pencil on the Scantron sheets and make certain to fully erase any changes you make. Use this exam to check your answers on the key that will be posted online cm = 1 in 454 g = 1 lb 946 ml = 1 qt 5280 ft = 1 mile 16 oz = 1 lb 4 qt = 1 gal heat = (sp. Ht.) X (mass) X ( Temp) T (K) = T ( C) T( F) = (1.8 X T( C)) cal = J

2 1. Given the following structures, which of them possesses a molecular dipole? A) A and D B) A only C) C only D) B and C 2. Which one of the following forms of radiation has the shortest wavelength? A) visible waves B) radio waves C) x-rays D) infrared waves 3. Which family in the periodic table has the following general electron configuration, [NG] ns 2 np 4, where NG represents a noble gas? A) Group VIB B) Group VIA C) Group IVA D) Group IIA 4. Which one of the following orbitals represents a p orbital? 5. In diatomic nitrogen, how many electrons are shared between the nitrogen atoms? A) 6 B) 8 C) 3 D) 2

3 6. With its one pair of nonbonding electrons on the nitrogen atom, what is the molecular geometry of ONCl? A) trigonal pyramidal B) bent C) trigonal planar D) linear 7. The electron configuration for selenide ion (Se 2- ) is A) [Kr] B) [Ar] C) [Ar] 4s 2 4p 6 D) 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 8. Given the unbalanced equation, Cr(NO 3 ) 3 (aq) + LiOH(aq) LiNO 3 (aq) + Cr(OH) 3 (s), how many grams of Cr(OH) 3 are produced from g of Cr(NO 3 ) 3? A) 8.5 g B) 3.5x10-4 g C) g D) 0.20 g 9. For the n = 5 shell, how many electrons are required to completely fill this shell? A) 50 B) 32 C) 18 D) The Lewis structure for ONCl can represented as O=N-Cl. How many nonbonding electrons are on O, N, and Cl atoms, respectively? A) 4, 2, 6 B) 4, 0, 6 C) 2, 2, 4 D) 0, 0, 6

4 11. The reaction between nitrogen and oxygen gases requires the absorption of 43 kj of energy per mole of nitrogen according to the following chemical equation, N 2 (g) + O 2 (g) 2 NO(g). How much energy must be absorbed by the reaction in order to consume moles of nitrogen? A) 15. kj B) kj C) 43 kj D) 420 kj 12. In the ground state, the electron in the hydrogen atom is found A) at the nucleus. B) in the n = 1 state. C) in the n = 0 state. D) in the l = 1 state. 13. Which list of chemical species could possess the electron configuration, 1s 2 2s 2 2p 6? A) Ne, O 2-, Na 1+ B) F 1-, Ne, Na 1+ C) F, Ne, Na D) Ne, Ar, Kr 14. One reaction that is responsible for acid rain is given by the balanced equation, 3NO 2 (g) + H 2 O(l) 2 HNO 3 (aq) + NO(g). If 3.5 moles of NO 2 react with 3.5 moles of H 2 O, 1.2 moles of NO are produced based on the limiting reactant concept. What is the percent yield if 0.81 moles of NO are experimentally produced? A) 68% B) 2.2% C) 148% D) 0.022% 15. The images of the orbitals (s,p,d) that are in the text represent the A) abstract nature of atoms. B) exact location of the electrons. C) electron density. D) symmetry of the atom.

5 16. How many orbitals and electrons are in an s subshell? A) 2 : 2 B) 2 : 1 C) 1 : 4 D) 1 : How many d orbitals can exist in a single subshell? A) 1 B) 3 C) 5 D) For the molecule PF 3, how many total valence electrons are associated with this molecule? A) 4 B) 26 C) 32 D) Given the balanced equation, Na 2 SO 4 (aq) + BaCl 2 (aq) 2 NaCl(aq) + BaSO 4 (s), if mol of sodium sulfate is allowed to react with mol of barium chloride, which one of the following is correct? A) sodium sulfate is the limiting reactant B) barium chloride is the reactant in excess C) barium chloride is the limiting reactant D) it is a stoichiometric reaction 20. The frequency of light is directly proportional to the A) amplitude. B) wavelength. C) energy. D) speed of light.

6 21. Which comparison of ionic radius is correct? A) Na + > F - B) S 2- > Cl - C) K + > Cl - D) K + > Na Based on Lewis dot symbols, phosphorus forms a -3 ion because A) it loses five electrons (dots) when forming an ionic compound. B) it needs two more electrons to meet the octet rule. C) it can form five covalent bonds. D) it gains three electrons (dots) when forming an ionic compound. 23. Arrange the following elements in order of increasing atomic radius; Al, Si, Ga, and Ge. A) Si < Al < Ge < Ga B) Ge < Ga < Si < Al C) Al < Si < Ga < Ge D) Si < Ge < Al < Ga 24. The percent yield for a given reaction is 45.4%. If the theoretical amount is predicted to be 2.22 g, what was the actual yield for the reaction? A) g B) 1.01 g C) 101 g D) 20.5 g 25. One reaction that is responsible for acid rain is given by the balanced equation, 3NO 2 (g) + H 2 O(l) 2 HNO 3 (aq) + NO(g). If 3.5 moles of NO 2 react with 5.0 moles of H 2 O, how many moles of NO can be produced? A) 7.0 moles B) 3.5 moles C) 1.2 moles D) 10. moles 26. Please indicate you are taking Version A of this exam by marking the A response on QUESTION 26 ON THE REVERSE SIDE OF THE SCANTRON SHEET. Failure to do this will invalidate your responses.

7 Answer Key for 2010S Exam 3A 1. A 2. C 3. B 4. C 5. A 6. B 7. A 8. C 9. A 10. A 11. A 12. B 13. B 14. A 15. C 16. D 17. C 18. B 19. C 20. C 21. D 22. D 23. A 24. B 25. C