Dr. Rick Fletcher. Clearly print your name in the name section of the Scantron answer sheet.

Transcription

1 Dr. Rick Fletcher Exam 3 Chemistry 101 April 18, 2011 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 ( o C) T( o F) = (1.8 X T( o C)) cal = J

2 1. The images of the orbitals (s,p,d) that are in the text represent the A) symmetry of the atom. B) electron density. C) abstract nature of atoms. D) exact location of the electrons. 2. Which list of chemical species could possess the electron configuration, 1s 2 2s 2 2p 6? A) F 1-, Ne, Na 1+ B) F, Ne, Na C) Ne, Ar, Kr D) Ne, O 2-, Na How many p orbitals can exist in a single subshell? A) 1 B) 2 C) 3 D) not enough information 4. A sample of plutonium is known to contain 4.5x10 18 atoms. How many moles of plutonium are present? A) 7.47x10-6 moles B) 1.34x10 5 moles C) 1.08x10 21 moles D) 9.30x10-22 moles 5. 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) barium chloride is the limiting reactant B) it is a stoichiometric reaction C) barium chloride is the reactant in excess D) sodium sulfate is the limiting reactant 6. A sample of N 2 O 5 is known to contain 4.3x10 24 molecules. How many nitrogen atoms are in this sample? A) 8.6x10 24 atoms B) 4.3x10 48 atoms C) 2.2x10 25 atoms D) 4.3x10 24 atoms

3 7. The reaction between sodium metal and chlorine gas produces 822 kj of heat energy for every chlorine molecule consumed [2 Na(s) + Cl 2 (g) 2 NaCl(s)]. If 8.21 moles of chlorine gas are consumed, how much heat will be given off? A) 822 kj B) 100. kj C) 6750 kj D) kj 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) 3.5x10-4 g B) 0.20 g C) 8.5 g D) g 9. Given the balanced equation, Na 2 SO 4 (aq) + BaCl 2 (aq) 2 NaCl(aq) + BaSO 4 (s), how many moles of Na 2 SO 4 are required to produce 0.45 g of BaSO 4? A) 0.22 moles B) not enough information C) moles D) moles 10. For an electron to occupy an excited state (n > 1), A) the electron must release energy. B) the magnetic component of radiation attracts the electron away from the nucleus. C) the electron must absorb energy. D) the positive charge of the nucleus must push it up. 11. A sample of dinitrogen tetraoxide has a mass of 1.5 g. How many moles of oxygen are present in this sample? A) mol B) mol C) mol D) mol

4 12. Given the following p orbital,, what is the probability that the electron is found at the point separating the two lobes? A) 90% probability B) zero probability C) 10% probability D) infinite probability 13. A sample of Cr 2 O 3 has a mass of 0.33 g. How many chromium atoms are in this sample? A) 1.3x10 21 atoms B) 2.6x10 21 atoms C) 9.1x10 25 atoms D) 3.9x10 21 atoms 14. 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 IIA B) Group IVA C) Group VIB D) Group VIA 15. Given the unbalanced equation, Cr(NO 3 ) 3 (aq) + LiOH(aq) LiNO 3 (aq) + Cr(OH) 3 (s), how many grams of Cr(NO 3 ) 3 are required to produce moles of Cr(OH) 3? A) 10.5 g B) 4.37x10-4 g C) 24.8 g D) g 16. What is the formula weight for barium phosphate, Ba 3 (PO 4 ) 2? A) amu B) amu C) amu D) amu 17. What is the mass of 4.3 moles of Se? A) 2.6 x g B) 7.1 x g C) 18 g D) 340 g

5 18. The frequency of light is directly proportional to the A) speed of light. B) energy. C) amplitude. D) wavelength. 19. 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, which substance will not be present after the reaction is complete? A) HNO 3 B) NO 2 C) NO D) H 2 O 20. In a particular reaction, 23.3 g of SO 2 is produced. If 70.3 g of SO 2 is predicted to be formed, what is the percent yield? A) 30.2% B) 0.331% C) 33.1% D) 302% 21. Which one of the following forms of radiation has the shortest wavelength? A) infrared waves B) x-rays C) visible waves D) radio waves 22. The molar mass of one empirical unit of the antidepressant rolicyprine (C 7 H 8 NO) is g/empirical unit. If the molar mass for rolicyprine is approximately 250 g/mol, how many empirical units are present in each molecular unit? A) 0.5 B) 3 C) 1 D) 2

6 23. Having one mole of carbon dioxide means that you have A) 1 mole of carbon atoms B) 6.022x10 23 moles of carbon C) 1 molecule of CO 2 D) 6.022x10 23 atoms of oxygen 24. A chemical reaction that absorbs energy is called an A) endergonic reaction. B) exergonic reaction. C) exothermic reaction. D) endothermic reaction. 25. How many moles are in 23.0 g of Na? A) moles B) 1.0 moles C) x moles D) 23.0 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.