DO NOT OPEN THIS EXAM UNTIL YOU ARE TOLD TO DO SO. Chemistry 101-D0D. Dr. Jason A. Halfen. Final Examination. December 16, 1999

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1 DO NOT OPEN THIS EXAM UNTIL YOU ARE TOLD TO DO SO Chemistry 101-D0D Dr. Jason A. Halfen Final Examination December 16, 1999 Name (Please print): Signature You will have two hours to complete this examination. There are a total of 11 pages in this exam including this cover page and a periodic table (the last page of the exam) which you may remove. Write answers to multiple choice questions in the space provided to the left of each question Show all work for your calculations in order to receive partial credit DO NOT WRITE BELOW THIS LINE Points from multiple choice section (75 possible): Points from short answer section (75 possible): Total points (150 possible): 1

2 1. The sublimation of solid carbon dioxide (CO 2 ) to gaseous CO 2 is best classified as a (a) chemical change (b) physical change (c) both a chemical change and a physical change (d) neither a chemical nor a physical change 2. How many significant figures are used in expressing the quantity kg? (a) seven (b) six (c) five (d) four 3. Human blood has a density of g/ml. What is the volume of a sample of blood that has a mass of g? (a) ml (b) ml (c) ml (d) 9001 ml 4. One-half Avogadro s number of sodium (Na) atoms would have a mass of (a) g (b) g (c) x g (d) x g 5. In the nucleus of the medically important isotope Tc, there are (a) 43 protons, 99 neutrons (b) 99 protons, 43 neutrons (c) 43 protons, 56 neutrons (d) 56 protons, 43 neutrons 6. Consider the electron configuration of sulfur (S). How many unpaired electrons are present in a neutral sulfur atom? (a) zero (b) four (c) three (d) two 7. Which of the following is a non-metal? (a) Mg (b) Al (c) I (d) Hg 2

3 8. Which of the following has the same number of valence electrons as Br? (a) Kr (b) Cl (c) Rb + (d) Br - 9. The correct formula for a compound containing Al 3+ and SO 4 2- ions is (a) Al 2 SO 4 (b) AlSO 4 (c) Al(SO 4 ) 3 (d) Al 2 (SO 4 ) A single covalent bond is formed when (a) a cation and an anion are found in close proximity to each other (b) two neutral atoms share a pair of electrons (c) two neutral atoms share a single electron (d) one neutral atom donates a single electron to another neutral atom, forming a cation/anion pair 11. Consider the reaction shown below. Which substance is reduced? 4 HCl (aq) + MnO 2 (s) Å Cl 2 (g) + 2 H 2 O (l) + MnCl 2 (aq) (a) Cl - in HCl (b) H + in HCl (c) Mn 4+ in MnO 2 (d) O 2- in MnO Which of the following is a single replacement reaction? (a) SO 3 + H 2 O Å H 2 SO 4 (b) HBr + KOH Å KBr + H 2 O (c) 2 HI Å H 2 + I 2 (d) CuO + H 2 Å Cu + H 2 O 13. Which species in the following reaction would be classified as spectator ions? CuCl 2 (aq) + 2 NaOH (aq) Å 2 NaCl (aq) + Cu(OH) 2 (s) (a) Na + and Cl - (b) Na + and OH - (c) Cu 2+ and OH - (d) Cu 2+ and Cl Increasing the temperature of a gas sample at constant pressure and molar amount of gas causes (a) the volume to decrease (b) the volume to increase (c) no change; the volume remains unchanged (d) a change that depends on the type of gas present 3

4 15. A solution is prepared by dissolving a small amount of salt in a beaker of water. The salt is referred to as the (a) solvent (b) solution (c) solute (d) precipitate 16. Determine the concentration, in units of molarity, of a solution that contains 100 g of glucose, C 6 H 12 O 6, present in 500 ml of solution. (a) M (b) 1.11 M (c) 200 M (d) M 17. What ions are present, and what are their concentrations, in a 0.35 M solution of K 3 PO 4? (a) K 3 +, 0.35 M; PO 4 -, 0.35 M (b) K 3+, 0.35 M; PO 4 3-, 0.35 M (c) K +, 1.05 M; PO 4 3-, 1.05 M (d) K +, 1.05 M; PO 4 3-, 0.35 M 18. When 50 ml of 6.0 M HCl are diluted to a new volume of 1.5 L, what is the new concentration of HCl? (a) 2.0 x 10 2 M (b) 20 M (c) 0.20 M (d) M 19. Consider the reaction H 2 SO 4 + H 2 O Å H 3 O + + HSO 4 -. Which of the following is the conjugate acid of H 2 O? (a) HSO 4 - (b) H 2 SO 4 (c) H 3 O + (d) SO Which of the following could not function as a Bronsted base? (a) HClO 4 (b) NaOH (c) NH 4 OH (d) Ca(OH) A solution of baking soda has a poh of 5.85, which means that the solution is (a) very slightly acidic (b) neutral (c) strongly acidic (d) basic 4

5 22. The ph of blood is maintained at a constant value through the use of a buffer. Calculate [OH - ] found in blood for which the ph is 7.4. (a) 3.98 x 10-8 M (b) 2.51 x 10-7 M (c) 1.0 x 10-7 M (d) 7.4 M 23. Which of the following particles is needed to complete the nuclear decay reaction shown below? U Å + Th 90 (a) a beta particle (b) a positron (c) an alpha particle (d) a gamma ray 24. Which of the following types of radiation is composed of particles that carry a negative charge? (a) beta particles (b) positrons (c) alpha particles (d) gamma rays 25. For the equilibrium A + B &'DQHTXLOLEULXm constant was determined to be 1.0. This means that at equilibrium, (a) there are far more reactant than products (b) there are far more products than reactants (c) there are equal numbers of products and reactants (d) the reaction is complete 26. The Gibbs free energy, G, is defined as G = H - T S, and is used to describe energy changes in chemical reactions. For any reaction to be spontaneous, it is true that (a) the Gibbs free energy must decrease (b) the Gibbs free energy must increase (c) the Gibbs free energy must remain unchanged (d) the Gibbs free energy of the products is greater than that of the reactants. 27. Carboxylic acids, molecules that contain a -CO 2 H group, are generally considered to be (a) strong acids (b) weak acids (c) weak bases (d) insoluble in water. 5

6 28. The bonding in alkanes makes use of (a) s and p atomic orbitals on C (b) sp hybrid orbitals on C (c) sp 2 hybrid orbitals on C (d) sp 3 hybrid orbitals on C 29. The conversion of methanol, CH 3 OH, to formaldehyde, H 2 CO, requires (a) oxidation of the carbon atom in methanol (b) reduction of the carbon atom in methanol (c) dehydration of the methanol molecule (d) reduction of the oxygen atom in methanol 30. What is the molecular formula of styrene, the organic compound shown in the stick drawing below? (a) C 8 (b) C 8 H 6 (c) C 8 H 7 (d) C 8 H 8 x 2.5 Number correct from multiple choice section Points from multiple choice section 31. Chemical Nomenclature. Provide the missing names or formulas for the following compounds. (10 points) Formula Name Formula Name KBr Iodine trichloride Sodium hydroxide N 2 O 4 (NH 4 ) 3 PO 4 Hydrogen peroxide Iron(III) nitrate CH 3 CO 2 H Cu 2 O Ammonia 6

7 32. Stoichiometry (a) The chemical weapon phosgene gas (COCl 2 ), used primarily during World War I, reacts with water in the lungs to form hydrochloric acid and carbon dioxide according to the following unbalanced reaction: COCl 2 + H 2 O +&O&2 2 What mass of HCl is produced when 12.5 g of COCl 2 react with excess water in the lungs? (8 points) (b) Sulfur dioxide (SO 2 ) is a major contributor to the formation of acid rain in the earth s atmosphere. The unbalanced reaction below shows how SO 2 is converted to sulfuric acid in the atmosphere: SO 2 + H 2 O + O SO 4 On May 18, 1990, when the Mt. St. Helen s volcano in the Pacific Northwest erupted, an estimated 4.0 x 10 8 kg of SO 2 were released into the atmosphere. If all of this SO 2 were eventually converted to sulfuric acid, what mass of H 2 SO 4 (in kg) would be produced? (8 points) 33. The interior volume of the Hubert H. Humphrey Metrodome in Minneapolis is 1.70 x L. How many moles of gas molecules are present in the dome if the pressure is 775 torr at 18 o C? (4 points) 7

8 34. Structure and Bonding (a) The following questions relate to the Na (sodium) atom. What types of subatomic particles are present, how many of each particle are present, and where in the atom are they located? A drawing may be useful in your response (5 points). Is sodium likely to form ionic compounds or molecular compounds? Provide at least one example. (2 points) What changes to the sodium atom occur when it forms the compounds you described above? (3 points) (b) Consider the two triatomic molecules water (H 2 O) and carbon dioxide (CO 2 ). Why do these two molecules have different geometries (shapes)? Be sure to include Lewis structures and accurately drawn pictures of these two molecules as part of your answer. (10 points). 8

9 35. What is the difference between a strong acid and a weak acid? Provide examples of each (5 points). 36. When the stomach isn t being stimulated by food, it generally produces about 2.3 x 10-3 mol of HCl in 50 ml of stomach acid solution per hour. Calculate the ph and the poh of this gastric juice solution. (5 points) 37. Vitamin C is thought to protect our stomachs from cancer by converting the nitrite ions present in many preserved foods to NO gas: NO 2-12 Is the nitrite ion oxidized or reduced in this reaction? Be sure to justify your answer. (3 points) Is Vitamin C an oxidizing agent or a reducing agent? (2 points) 9

10 38. Write balanced equations for 4 of the following 6 reactions. Circle those reactions you choose to complete and wish to have graded; otherwise, only the first 4 reactions will be graded. (10 points, 2.5 points each) (a) CH 3 CO 2 Na (aq) + H 2 O (l) (b) AgNO 3 (aq) + BaCl 2 (aq) (c) Positron emission from S (d) H 3 PO 4 (aq) + NaHCO 3 (aq) (e) HNO 3 (aq) + H 2 O (l) (f) Incomplete combustion of C 6 H 10 I hope you found your experience in Chemistry 101 to be intellectually stimulating and rewarding. Thanks to those of you who have sent kind thoughts and prayers during my sister s illness. Send more good vibes to Austria on January 23, to help me finish the "Dolomitenlauf" cross-country ski marathon (65 km; 40 mi) through the Dolomite mountains, "foothills" of the Alps. Have a pleasant and safe holiday season. See you in January! 10

CHEMISTRY 101 SPRING 2010 FINAL FORM B DR. KEENEY-KENNICUTT PART 1

NAME (Please print ) CHEMISTRY 101 SPRING 2010 FINAL FORM B DR. KEENEY-KENNICUTT Directions: (1) Put your name on PART 1 and your name and signature on PART 2 of the exam where indicated. (2) Sign the