CHEM 101 WINTER FINAL EXAM

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1 CHEM 101 WINTER FINAL EXAM On the answer sheet (Scantron) write you name, student ID number, and recitation section number. Choose the best (most correct) answer for each question and enter it on your answer sheet. Avogadro s Number: mol -1 P 1 V 1 / n 1 T 1 = P 2 V 2 / n 2 T 2 Speed of Light: c = 3.00 x 10 8 m s -1 Planck s Constant: h = x J s PV = nrt d = PM / RT Rydberg Constant: R = x J R = L atm mol -1 K -1 E = hc/λ = hυ 1 atm = 760 Torr = 760 mm Hg q = mcδt Specific Heat of Water = J g -1 C -1 h 1 d 1 = h 2 d 2 C 1 V 1 = C 2 V 2 1. Please chose the letter a as your answer for this question. 2. Which of the following represents either a chemical property or a change in a chemical property? a. Br 2 (l) Br 2 (g) b. Gold is both very malleable and very ductile. c. High purity water has a resistance 18.2 MΩ cm d. A metal more easily conducts electricty at a low temperature. e. 2 H 2 O (l) 2 Η 2 (g) + Ο 2 (g) 3. Which of the following compounds can be dissolved in water to give a solution that conducts electricity? a. C 8 H 18 (2,2,4,-trimethylpentane) b. C 6 H 12 O 6 (glucose) c. CHCl 3 (chloroform) d. KClO 4 (potassium perchlorate) e. (CH 3 ) 2 CHOH (isopropyl alcohol) 4. Which of the following is not a metal? a. cobalt (Co, atomic number 27) b. indium (In, atomic number 49) c. selenium (Se, atomic number 34) d. lithium (Li, atomic number 3) e. beryllium (Be, atomic number 4) 1

2 5. When neutral atoms gain one or more electrons, are formed. a. hadrions b. cations c. fermions d. deuterions e. anions 6. Which two of the following represent a pair of isotopes? P P P S S I. II. III. IV. V. a. I and IV b. III and IV c. I and III d. I and II e. II and V 7. Which of the following consists of a pair of allotropes? a. air and oxygen b. phosgene, O=C (Cl) 2 and phosphine, PH 3 c. red phosphorus and white phosphorus d. carbon tetrachloride and carbon tetrabromide e. yellow sulfur and yellow phosphorus 8. An element that has 24 protons, 24 electrons, and 28 neutrons has a molar mass of. a. 76 amu. b. 56 amu. c. 52 amu. d. 48 amu. e. 84 amu. 9. Three elements that are likely to have similar chemical and physical properties are: a. Ca, Co, Cr b. H, He, Ne c. Pb, Bi, Po d. B, C, Si e. Na, K, Li 10. Which formula and name combination is incorrect? a. SF 6 and sulfur hexafluoride b. N 2 O 3 and dinitrogen tetraoxide c. P 4 O 10 and tetraphosphorus decaoxide d. AsBr 5 and arsenic pentabromide e. SeF 4 and selenium tetrafluoride 2

3 11. What is the correct general formula for a straight-chain alkene? a. C n H 2n+2 b. C n H n+2 c. C n H n d. C n H 2n 2 e. C n H 2n 12. Determince the correct combination of protons and electrons for the phosphide ion, P 3. a. 18 protons and 10 electrons b. 16 protons and 12 electrons c. 15 protons and 18 electrons d. 15 protons and 12 electrons e. 12 protons and 24 electrons 13. Determine the number of moles of water in a liter of water (density = g / L), and the Molarity of water, respectively a. 56 and 74 b. 18 and 56 c. 18 and 18 d. 18 and 74 e. 56 and Which statement regarding the complete combustion of a hydrocarbon is incorrect? a. The hydrocarbon is consumed in the reaction and must be shown in the balanced chemical equation. b. Heat is produced in the reaction but does not need to be shown in the balanced chemical equation. c. Balancing the chemical equation requires knowledge of the physical state of each reactant and each product. d. Oxygen is the oxidizing agent and must be shown in the balanced chemical equation. e. Carbon dioxide and water are produced in the reaction and must be shown in the balanced chemical equation. 15. Assuming an excess of aluminum, how many moles of aluminum tribromide can be produced from 111 moles of bromine? 2 Al + 3 Br 2 2 AlBr 3 a. 167 b. 56 c. 111 d. 148 e Classify the following reaction. Ni(ClO 4 ) 2 (aq) + K 2 S (aq) a. decomposition b. exchange c. combustion d. displacement e. combination 3 2 KClO 4 (aq) + NiS (s)

4 17. The Roman numerals in the reaction given represent the coefficients in the balanced chemical equation. What are the values of the coefficients? I Al (s) + II CuSO 4 (aq) III Al 2 (SO 4 ) 3 (aq) + IV Cu (s) I II III IV a b c d e What is the net ionic equation for the the following reaction? 3 Ca(NO 3 ) 2 (aq) + 2 H 3 PO 4 (aq) Ca 3 (PO 4 ) 2 (s) + 6 HNO 3 (aq) a. N + + NO 3 NNO 3 b. P NO 3 P(NO 3 ) 2 c. 3 Ca 2+ (aq) + 2 PO 3 4 (aq) Ca 3 (PO 4 ) 2 (s) d. 2 H + + NO 6 2 HNO 3 e. 2 H 3 PO 4 (aq) 6 HNO 3 (aq) 19. Which of the following would be expected to be present in a 1. M aqueous solution of perchloric acid, HClO 4? a. Cl b. PO 4 3 c. HCl d. H e. H 3 O What is the reducing agent in the reaction below? MnO 4 (aq) + 8 H + (aq) + 5 e Mn 2+ (aq) + 4 H 2 O a. H + b. e c. Mn 2+ d. H 2 O e. MnO Using high purity water, to what final volume would ml of a 1.00 x 10 7 ppb (parts per billion) solution of arsenic need to be diluted to be useable as a Federal drinking water testing standard at an arsenic concentration of ppb? a x 10 8 ml b ml c. 18,000 ml d. 22,400 ml e x 10 5 ml 4

5 22. Determine the specific heat of uranium (atomic number 92, molar heat capacity = J mol 1 C 1 ). a J g 1 C 1 b J g 1 C 1 c J g 1 C 1 d J g 1 C 1 e J g 1 C What is the enthalpy change if 28 moles of carbon dioxide are formed by the following reaction? C 4 H 10 (g) + 13/2 O 2 (g) 4 CO 2 (g) + 5 H 2 O(g) H = 1895 kj a kj b. 28,000 kj c. 13,265 kj d kj e. 190 kj 24. A chemical reaction is exothermic when a. the strength of bonds broken is greater than the strength of bonds formed. b. weak bonds are broken and stronger bonds are formed c. no bonds are formed. d. strong bonds are broken and weaker bonds are formed. e. the strengths of all bonds broken and formed are the same. 25. Calculate the standard enthalpy change, H, for the following reaction PbCl 4 (l) Pb(Cl) 2 (s) + Cl 2 (g) using the information given below: Pb (s) + Cl 2 (g) PbCl 2 (s) H = kj a kj b kj c kj d kj e kJ Pb (s) + 2 Cl 2 (g) PbCl 4 (l) H = kj 26. The standard enthalpies of formation for several substances are given below: CO (g) kj/mol CO 2 (g) kj/mol H 2 O (g) kj/mol H 2 O (l) kj/mol H 2 O 2 (l) kj/mol CH 3 OH (g) kj/mol C 3 H 8 (g) kj/mol CH 3 OH (l) kj/mol Determine the H for the reverse of the reaction shown below. a kj b kj c kj d kj e. 575 kj C 3 H 8 (g) + 5 O 2 (g) 3 CO 2 (g) + 4 H 2 O (l) 5

6 27. A 10.0 mole sample of CH 4 reacts completely with excess oxygen in a calorimeter having a heat capacity of 3915 J/ C. The calorimeter contains 1270 g of water. Determine the total amount of energy produced by the combustion. CH 4 (g) + 2 O 2 (g) 2 H 2 O(g) + CO 2 (g) H = kj a kj b. 127 kj c kj d. 392 kj e kj 28. Light has a wavelength of 280 nm. What is its frequency? a Hz b Hz c Hz d Hz e Hz 29. Determine the energy of a photon that has a wavelength of 280 nm. a J b J c J d J e J 30. Which values for the fourth (spin) quantum number are allowed for n = 1? a. m s = + b. m s = 0, 1, 2 c. m s = 1, 0, +1 d. m s = 0, 1, 2, 3, 4 e. m s = 0, 1, 2, How many orbitals and electrons, respectively, can be contained in each p subshell? a. 3 6 b c d e Which of the following corresponds to the electron configuration of a noble gas? a. 1s 2 2s 2 2p 6 3s 2 3p 5 b. 1s 2 2s 2 c. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 2 4p 3 d. 1s 2 2s 2 2p 6 3s 2 3p 6 e. 1s 2 2s 2 2p 4 6

7 33. Atoms and ions that have identical electron configurations are referred to as being a. isoelectronic. b. isopiestronic. c. ferromagnetic. d. diamagnetic. e. paratronic. 34. How many electrons will be in the correctly drawn Lewis Structure for the acetate anion, CH 3 COO? a. 22 b. 23 c. 17 d. 24 e Assume that all of the following are straight-chain hydrocarbons. Which compound will contain a triple bond? a. C 2 H 6 b. C 8 H 16 c. C 13 H 28 d. C 9 H 16 e. C 6 H In straight-chain organic molecules, cis-trans isomerism is a possibility only if the molecule contains at least one a. carbon-carbon single bond b. carbon-oxygen single bond c. carbon-carbon double bond d. carbon-oxygen double bond e. carbon-carbon triple bond 37. Of the elements shown, which is the most electronegative? a. calcium, Ca, atomic no. 20 b. nitrogen, N, atomic no. 7 c. gallium, Ga, atomic no. 31 d. selenium, Se, atomic no. 34 e. strontium, Sr, atomic no Which properly shows the formal charges on the atoms in phosgene, O=C (Cl) 2? a. +1 on oxygen, 3 on carbon, +1 on chlorine b. 1 on oxygen, +4 on carbon, 4 on chlorine c. 0 on oxygen, 0 on carbon, 0 on chlorine d. 1 on oxygen, +1 on carbon, 2 on chlorine e. 2 on oxygen, +4 on carbon, 1 on chlorine 7

8 39. Construct correct Lewis dot structures for the three molecules below. Which compound(s) exceed(s) the octet rule? CF 4 SeF 4 SiF 4 I II III a. III b. II and III c. I, II, and II d. II e. I 40. VSEPR Theory attempts to electron-pair. a. minimize, repulsions b. eliminate, attractions c. minimize, collisions d. maximize, attractions e. maximize, repulsions 41. Assuming that there are no lone pairs of electrons on the central atom, using VSEPR Theory predict the molecular geometry consistent with one, three, and five bonded electron pairs, respectively. a. linear, trigonal planar, trigonal bipyramidal b. tetrahedral, trigonal bipyramidal, octahedral c. linear, tetrahedral, hexagonal d. angular, trigonal pyramidal,octahedral e. linear, trigonal pyramidal, pentahedral 42. Draw the Lewis dot structure for trimethylamine, N(CH 3 ) 3, and then use VSEPR Theory to predict the electron-pair geometry, the molecular geometry, and to estimate the C-N-C bond angle, respectively. a. tetrahedral, trigonal pyramidal, b. tetrahedral, tetrahedral, c. tetrahedral, trigonal square planar, d. square planar, square planar, 90 e. trigonal bipyramidal, tetrahedral, Which of the following molecules is/are non-polar? I. SiH 3 F II. SiHF 3 III. SiH 2 F 2 IV. SiF 4 a. I and II b. I, II, and III c. II, III, and IV d. IV only e. II only 8

9 44. What is the major type of force that must be overcome to allow each of the processes below, in the order I to IV? I. the evaporation of liquid CH 3 CH 2 OH II. the vaporization of liquid CHCl 3 III. the sublimation of solid I 2 IV. the boiling of liquid C 5 H 12 a. hydrogen bonding, dipole-dipole, London (dispersion) forces, London (dispersion) forces b. hydrogen bonding, London (dispersion) forces, dipole-dipole, dipole-dipole c. London (dispersion) forces, covalent bonding, dipole-dipole, dipole-dipole d. London (dispersion) forces, London (dispersion) forces, London (dispersion) forces, London (dispersion) forces e. dipole-dipole, dipole-dipole, London (dispersion) forces, London (dispersion) forces 45. Determine the height (in mm) of a column of toluene in a barometer at a pressure of 790 mm Hg. The densities of mercury and toluene are and g/cm 3, respectively. a b c d e Assuming ideal gas behavior, calculate the number of moles of phosphine gas, PH 3, that occupy 8.2 L at STP. a b c d e Assuming ideal gas behavior, what is the density (in g/l) of arsine gas, AsH 3, at 60 C and 0.25 atm of pressure? a. 9.9 b c d e A mixture of He and O 2 exerts a total pressure of 2.24 atm. The partial pressure of oxygen is 1.40 atm. What is the mole fraction of helium? a b c d e

10 49. Under what conditions do real gases most closely approximate the behavior of ideal gases? a. low pressure and high temperature b. high pressure and low temperature c. all real gases behave like ideal gases at all temperatures and pressures d. high pressure and high temperature e. low pressure and low temperature 50. Which of the following is the correct sequence for the three principle types of reactions which make up a free-radical process? a. substitution, elimination, termination b. initiation, propagation, termination c. initiation, elimination, termination d. elimination, termination, substitution e. initiation, substitution, termination 51. Which of the following greenhouse gases is considered to be the principal global warming gas generated by the combustion of fossil fuels in electric power plants and internal combustion engines? a. water vapor b. carbon dioxide c. ozone d. methane e. all of the above 10