Name Chemistry 111 Section FINAL EXAM Total Points = TA Wednesday, 3:20 PM 200 Directions: December 12, 2007 1. Each student is responsible for following directions. Read this page carefully. 2. Write your name and other requested information on this page and on the separate answer sheet. 3. CDE your name on the answer sheet using an ordinary (#2) pencil. 4. CDE your correct 10-digit identification number (PUID) on the answer sheet. THIS IS VERY IMPRTANT! 5. CDE your section number on the answer sheet. Please use all four digits, 0101, 0102, 0201, etc. This is also very important! 6. Put all calculations on the examination pages. D NT PUT ANY EXTRA MARKS N THE CMPUTER ANSWER SHEET! 7. This exam consists of 40 multiple-choice questions worth 5 points each. Choose the one best or correct answer for each question and write it both on your exam paper and on the computer answer sheet. The computer answer sheet is the only one that will be graded! 8. This exam consists of 9 pages plus a Periodic Table. Please check to be sure that you have them all! Useful Information Avogadro s number = 6.022 x 10 23 END F EXAM 1) Please make sure that you have entered 40 answers on your scan sheet. 2) Make sure that you have entered your name, ID number, and lab section number (4 digits). 3) You MUST turn the scan sheet in to your TA before leaving the exam!
Chem 111 Final Exam 12/12/07 2 E 1. The density of ice is slightly lower than the density of water. This means: Water is a homogeneous mixture. Converting water to ice is a chemical change. Ice will sink in water. Converting water to ice involves a loss of atoms. Converting water to ice involves volume change C 2. Which of the following are chemical changes? i) rusting of a nail ii) a cookie being metabolized iii) decomposition of water into hydrogen and oxygen gases iv) alcohol being evaporated v) butter melting in a heated copper pot i i, ii i, ii, iii i, ii, iii, iv i, ii, iii, iv, v B 3. Which of the following conversions is correct? 1 cm = 0.001 m 12.5 cm = 125 mm 0.092 m = 9.2 mm 20 ml = 0.2 L 0.3 g = 30 mg B 4. How many significant figures should there be in the answer to the following? (3.15 1.06) + (21 1.773) = 1 2 3 4 5 A 5. A 3.00 L bottle has a mass of 1.13 kg. When filled with a liquid its mass increases to 3.38 kg. What is the density of the liquid in g/ml? 0.750 75.0 0.000750 1.99 0.666
Chem 111 Final Exam 12/12/07 3 B 6. All atoms of a given element have the same: mass. number of protons. number of neutrons. number of electrons and neutrons. density. C 7. D 8. An atom of phosphorus-32 contains protons, electrons and neutrons. Protons electrons neutrons 32 32 32 31 17 15 15 15 17 15 17 15 31 15 17 What is the mass of one million atoms of Mg? 1,000,000 amu 24,310,000,000 amu 0.2431 mg 4.037 x 10 14 mg 2.431x 10 17 g A 9. How many anions are there in 0.500 g of magnesium bromide? 3.27 10 21 2.90 10 21 1.64 10 21 2.35 10 21 C 10. How many grams of KCl are needed to prepare 250. ml of a 0.400 M KCl solution? 5.31 g 6.78 g 7.46 g 8.52 g 9.34 g B 11. When 10. ml of pure ethyl alcohol (density 0.79 g/ml, M.M. = 46.07 g/mol) is diluted to 500. ml, what is the molarity of the final solution? 0.17 M 0.34 M 0.68 M 1.7 M 3.4 M
Chem 111 Final Exam 12/12/07 4 D 12. If X represents an element of group IIIA, what is the general formula for its oxide? X 3 4 X X 3 2 X 2 3 X 2 C 13. What is the oxidation number of chromium in K 2 Cr 2 7? 2 +2 +6 +7 +12 E 14. Which of the following statements is based on the Bohr model of the atom? Nearly all of an atom s mass is located in its tiny, positively charged nucleus. Electrons have wave-like characters. It is impossible to determine precisely an electron s position and energy. The nucleus is composed of protons and neutrons. Electrons lose energy when they drop from an n = 2 to an n = 1 energy level. E 15. In a ground-state sodium atom, the sublevel is partially filled. 2s 2p 3p 3d 3s A 16. Which pair of elements is most likely to form an ionic compound with each other? barium, bromine calcium, sodium oxygen, fluorine sulfur, fluorine nitrogen, hydrogen B 17. Which of the following elements is the most abundant in the earth s crust? H C Si N
PP Chem 111 Final Exam 12/12/07 5 C 18. Which of the following atoms or ions does not have an octet? Cl 2 Cs Ar 3 A 19. Which of the following compounds is an electrolyte? LiF C 2 H 5 H (ethanol) C 6 H 12 6 (glucose) sucrose (table sugar) CH 4 A 20. The Lewis dot structure of phosphate ( P 4 3 )is best represented by: 3 3 P P 3 3 P P A 21. Which of the following is not true about the element S? It is more electronegative than oxygen. Its atomic radius is smaller than that of arsenic. It has 6 valence electrons. It has an ionization energy higher than that of silicon. A 22. Sort the following atoms in order of increasing electronegativity. Cs < Y < Ga < P < < F F < < Cs < Y < Ga < P Cs < F < Ga < < P < Y Cs < Ga < Y < < P < F F < < Ga < P < Y < Cs
Chem 111 Final Exam 12/12/07 6 C 23. The molecular shape of PCl 3 is: bent trigonal planar trigonal pyramidal tetrahedral A 24. Which of the following bonds would be the most polar? C F C Cl C Br C I All are equally polar. A 25. A 2.40 g sample of powdered molybdenum was heated in pure oxygen. The compound produced had a mass of 3.00 g. What is its empirical formula? Mo 2 3 Mo 3 4 Mo 2 5 Mo Mo 2 A 26. The mass percentage of H in propane (C 3 H 8 ) is: 18.3 81.7 30.3 69.7 24.9 C 27. When the following equation is balanced, what is the coefficient of 2? 2 4 6 8 10 C 4 H 9 H + 2 C 2 + H 2
Chem 111 Final Exam 12/12/07 7 C 28. Which of the following net ionic equations best describes the result of the mixing of FeBr 3 (aq) and LiH(aq)? Fe 3+ + Br FeBr Li + + Br LiBr Fe 3+ + 3 H Fe(H) 3 Fe 3+ + H Fe(H) Li + + 2 Br LiBr 2 E 29. Magnesium reacts with nitrogen to yield an ionic compound. The formula of this compound is: MgN Mg 2 N MgN 2 MgN 3 Mg 3 N 2 D 30. In a combustion analysis of a 0.152-g sample of the artificial sweetener aspartame, it was found to contain 6.18% of H, 57.10% of C, 9.54% of N, and 27.18% of. The molar mass of aspartame is 294 g/mol. What is its molecular formula? C 13 H 16 N 3 5 C 7 H 9 N 2 C 5 H 6 N 2 C 14 H 18 N 2 5 A 31. Which of the following is the best example of a correctly balanced equation? P 4 + 6 H 2 4 PH 3 0 P 4 + 6 H 2 4 PH 3 2 P 4 + 12 H 2 8 PH 3 P 4 + 3 H 2 PH 3
B 32. Chem 111 Final Exam 12/12/07 8 Balance the following word equation, then answer the question that follows. Sodium carbonate reacts with calcium nitrate to form sodium nitrate and calcium carbonate. The coefficient of the sodium nitrate in the balanced equation is: 1 2 3 4 5 Use the following choices to answer questions 33 34: combustion combination decomposition single replacement double replacement B 33. Ca + H 2 Ca(H) 2 E 34. Cd(N 3 ) 2 + Na 2 S CdS + 2 NaN 3 B 35. 77.21 ml of H 2 S 4 is used to completely react with 3.299 g of NaHC 3 according to the unbalanced equation below. What is the molarity of the H 2 S 4? NaHC 3 (aq) + H 2 S 4 (aq) C 2 (g) + Na 2 S 4 (aq) + H 2 (l) 0.5086 M 0.2543 M 1.017 M 0.2178 M 0.4356 M A 36. Which statement below is true when 10 g of nitrogen reacts with 5.0 g of hydrogen to produce ammonia? N 2 (g) + 3 H 2 (g) 2 NH 3 (g) Approximately 2.8 grams of hydrogen are left over. Hydrogen is the limiting reactant. Nitrogen is the excess reactant. The theoretical yield of ammonia is 14 g.
Chem 111 Final Exam 12/12/07 9 A 37. Phosphorus reacts with oxygen according to the following equation: P 4 (s) + 3 2 (g) P 4 6 (s) If a mixture of 71.9 g of phosphorus and 37.1 g of oxygen produces 42.6 g of P 4 6, the percent yield for the reaction is closest to: 50.2% 99.9% 33.4% 16.7% 42.6% A 38. Methanol is mostly produced by the reaction of carbon monoxide (C) with H 2. C + 2 H 2 CH 3 H For a reaction involving 36 g of C and 5.5 g of H 2, the theoretical yield of methanol is: 41 g 52 g 36 g 44 g 31 g B 39. When 24.3 g of Mg was placed in a beaker of hydrochloric acid, a vigorous reaction produced hydrogen gas and magnesium chloride. When the reaction was complete, how many liters of 1.0 M HCl reacted? Mg + 2 HCl MgCl 2 + H 2 1.0 2.0 3.0 4.0 5.0 C 40. How many moles of H 2 can be produced from the combustion of 1.5 moles of propane (C 3 H 8 )? 2 4 6 8 10