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1 CHEM Lab Section Number: Name (printed): Signature: This exam consists of 36 questions all of equal value for a total of 225 points. Make sure that your test has all of the pages. Please read each problem carefully. There are no intentionally misleading questions; each problem should be taken at its face value. Please mark your answers on the Scantron sheet provided to you and on the actual exam. You will be given a periodic table and an exam information sheet to use during the exam. You may remove it from the exam make it more accessible. You may also use the designated Casio fx-300ms-plus calculator or equivalent non-programmable non-graphing scientific calculator during the exam. Use the back pages of the test as scratch paper. You are not allowed to use any devices capable of accessing the internet, textbooks, notes, or homemade reference sheets during the exam. You may leave if you finish the exam early. Give the exam and the information sheet to your TA and leave quietly without disturbing other students. Before leaving, check that all your answers have been properly entered on the Scantron sheet and the exam and that your name is written on every page of the exam and on the Scantron sheet. All cell phones and electronic devices must be turned off and put away. Please remove all hats and caps. Place your books and all papers out of sight under your seat. If the TA believes that you might be looking at your neighbor s paper, you will be asked to move to a new location. Exam scores will be posted on Blackboard as soon as the grading is complete. Your test will be returned to you in the first lab meeting of next week. If you have any questions regarding the grading of your exam, please notify your TA. The time available for the exam is 120 minutes. Good luck! 1 of 12

2 Name: Lab Section #: Please mark your answers on the scantron sheet using a #2 pencil and also mark your answers on the exam itself. Mark Test From A on your scantron. 1. A g sample of an organic compound containing C, H and O is analyzed by combustion analysis and g of CO2 and g of H2O are produced. In a separate experiment, the molar mass is found to be g/mol. Determine the empirical formula and the molecular formula of the organic compound. (a) CHO, C2H2O2 (b) CH2O, C2H4O2 (c) CHO2, C2H2O4 (d) CH2O, CH2O (e) C2H2O,C4H4O2 2. A sample of aluminum metal absorbs 9.86 J of heat, upon which the temperature of the sample increases from 23.2 C to 30.5 C. Since the specific heat capacity of aluminum is 0.90 J/g. K, the mass of the sample is g. (a) 72 (b) 8.1 (c) 1.5 (d) 65 (e) How many total atoms are in one mole of CH3OH? (a) 6 (b) 6.0 x (c) 12.0 x (d) 3.6 x (e) 3 4. What is the percent yield of water if 0.90 g of water is obtained when 29.0 g of butane is burned in excess oxygen? The unbalanced chemical equation is the following (Hint: Balance the equation first) _ C4H10(g) + _O2(g) _CO2(g) + _H2O(g) (a) 0.02% (b) 2.0% (c) 10% (d) 36% (e) 21% 2 of 12

3 5. Arrange the following ions in order of increasing ionic radius: Cs +, Ba 2+, Te 2-, I - (a) Cs + < Ba 2+ < Te 2- < I - (b) Ba 2+ < Cs + < Te 2- < I - (c) Ba 2+ < Cs + < I - < Te 2- (d) Cs + < Ba 2+ < I - < Te 2- (e) Te 2- < I - < Cs + < Ba Consider the following reaction: 2Fe2O3(s) + 3C(s) 4Fe(s) + 3CO2(g) The compound being oxidized(compound Ox) and the oxidizing agent(oa) are: (a) compound Ox: C and OA: C (b) compound Ox: C and OA: Fe2O3 (c) compound Ox: Fe2O3 and OA: Fe2O3 (d) compound Ox: Fe2O3 and OA: C (e) compound Ox: Fe2O3 and OA: C 7. Which one of the formulas for ionic compounds below is incorrect? (a) SrCl2 (b) Cs2S (c) AlCl3 (d) Al3P2 (e) CaSe 8. The electronic structure of the NO3 molecule is best represented as a resonance hybrid of equivalent structures. (a) 2 (b) 3 (c) 4 (d) 5 (e) This molecule does not exhibit resonance. 9. Which of the following terms accurately describes the energy associated with the process: (a) electron affinity (b) binding energy (c) ionization energy (d) electronegativity (e) none of these F(g) + e - F - (g) 3 of 12

4 10. A chemical reaction is run in which 449 J of heat are generated and internal energy changes by -94 J, calculate the work change for the system? (a) -543 J (b) 543 J (c) 355 J (d) -355 (e) none of the above 11. Silver nitrate and aluminum chloride react with each other by exchanging anions: 3AgNO3 (aq)+ AlCl3 (aq) Al(NO3)3 (aq) + 3AgCl (s) AlCl3? What mass in grams of AgCl is produced when 4.22 g of AgNO3 react with 7.73 g of (a) 24.9 g (b) 11.9 g (c) 3.56 g (d) 4.22 g (e) 17.6 g 12. Which of the following is a correct set of quantum numbers for an electron in a 4d orbital? (a) n = 5, l = 3, ml = +1 (b) n = 5, l = 2, ml = +3 (c) n = 4, l = 3, ml = 0 (d) n = 4, l = 2, ml = +1 (e) n = 4, l = 2, ml = Gamma ray radiation has wavelengths from to m, whereas the wavelength region for visible light is 400 to 700 nm. The frequency of Gamma ray radiation is visible light and the speed of Gamma ray radiation is visible light. (a) higher than, higher (b) lower than, lower (c) higher than, lower (d) higher than, same as (e) lower than, same as 14. Which of the ionic compounds listed below would you expect to have the highest lattice energy? (a) Al2O3 (b) Na2O (c) NaF (d) MgS (e) Rb2O 4 of 12

5 15. Given the standard enthalpy changes for the following two reactions: (1) Sn(s) + Cl2(g) SnCl2(s)... ΔH = kj (2) Sn(s) + 2Cl2(g) SnCl4(l)...ΔH = kj what is the standard enthalpy change for the reaction: (3) SnCl2(s) + Cl2(g) SnCl4(l)...ΔH =? (a) kj (b) kj (c) kj (d) kj (e) kj 16. How much energy would be required to ionize(remove the final electron from) a He + ion if the electron was in the n=2 level? Would it require more or less energy if the electron was in the n=4 level? (a) J, more (b) J, less (c) J, more (d) J, less (e) J, same 17. Listed below are the energies for the sequential ionizations of an atom. Based on these values determine which element was being ionized. IE1 IE2 IE3 IE4 IE5 IE6 IE7 Energy (kj/mol) (a) Oxygen (b) Silicon (c) Magnesium (d) Phosphorous (e) Fluorine 5 of 12

6 18. Consider the following pairs of liquids. Which pairs are miscible (which is soluble with each other)? 1. 1-Hexanol, C6H13OH, and hexane, C6H12 2. water and methanol, CH3OH 3. water and hexane (a) 1, 2 only (b) 2 only (c) 1 only (d) 1,2,3 (e) 2, 3 only 19. Assume that the atmospheric pressure outside the body is 760 mm Hg. Assuming you are neither inhaling nor exhaling, the percent of gases in your alveoli is as follows: N2 = 74.9%, O2 = 13.6%, CO2 = 5.3%. According to Dalton's Law, the partial pressure of oxygen in your alveoli is approximately (a) 103 mm Hg (b) 136 mm Hg (c) 225 mm Hg (d) 569 mm Hg (e) 760 mm Hg 20. The phase diagram for xenon has a solid-liquid curve with a positive slope. Which of the following is true? (a) Solid xenon has the same density as liquid xenon. (b) The phase diagram cannot be used to predict which phase of xenon is denser. (c) Freezing xenon is an endothermic process. (d) Solid xenon has a higher density than liquid xenon. (e) None of the above statements is true g sample of water vapor, initially at 155 C is cooled at atmospheric pressure, producing ice at 55 C. Calculate the amount of heat energy lost by the water sample in this process, in kj. Use the following data: Hfus Hvap ch2o(s) ch2o(l) ch2o(g) 336 J/g 2260 J/g 2.09 J/g C 4.18 J/g C 1.84 J/g C (a) -5.4 kj (b) kj (c) kj (d) kj (e) kj 6 of 12

22. Octane has a vapor pressure of 40. torr at 45.1 C and 400. torr at 104.0 C. What is its heat of vaporization? (a) 46.0 kj/mol (b) 39.0 kj/mol (c) 590 kj/mol (d) 710 kj/mol (e) 0.0 kj/mol 23.

7 22. Octane has a vapor pressure of 40. torr at 45.1 C and 400. torr at C. What is its heat of vaporization? (a) 46.0 kj/mol (b) 39.0 kj/mol (c) 590 kj/mol (d) 710 kj/mol (e) 0.0 kj/mol 23. Examine the phase diagram to the right and identify the feature represented by point A. (a) melting point (b) triple point (c) critical point (d) sublimation point (e) boiling point 24. Examine the phase diagram to the right and determine what phase exists at point F. (a) gas (b) gas + liquid (c) liquid (d) solid (e) supercritical fluid 25. Neon atoms are attracted to each other by (a) London dispersion forces (b) dipole-dipole forces (c) hydrogen bonding (d) covalent bonding (e) ion-dipole forces 7 of 12

8 26. What is the most important intermolecular force in hydrogen fluoride? (a) London dispersion forces (b) dipole-dipole forces (c) hydrogen bonding (d) covalent bonding (e) ion-dipole forces 27. When two pure substances are mixed to form a solution (a) entropy is conserved (b) there is an increase in entropy (c) there is a decrease in entropy (d) heat is absorbed (e) heat is released 28. For a given solution, which of the following concentration values will change as temperature changes? (a) mass percent (b) molality (c) molarity (d) mole fraction (e) none of the above 29. What is the molality of a solution prepared by dissolving 86.9 g of diethyl ether, C4H10O, in 425 g of benzene, C6H6? (a) 2.76 m (b) m (c) m (d) 2.01 m (e) none of the above 30. The solubility of the oxidizing agent potassium permanganate is 7.1% by mass in water at 25 C. What is the mole fraction of potassium permanganate in this solution? (a) 0.48 (b) (c) (d) 0.45 (e) of 12

9 31. Select the best Lewis structure for ClCN. (a) (b) (c) (d) (e) 32. Which of the following liquids is likely to have the highest surface tension? (a) Br2 (b) C8H18 (c) CH3OH (d) CH3OCH3 (e) Pb 33. Using the Born-Haber cycle calculate the enthalpy of formation for strontium chloride. Sr(g) Sr(s) Sr(g) Sr + (g) + e - Sr + (g) Sr 2+ (g) + e - Cl2(g) 2Cl(g) Cl(g) + e - Cl - (g) Sr 2+ (g) + 2Cl - (g) SrCl2(s) ΔH = -164 kj/mol ΔH = 549 kj/mol ΔH = 1064 kj/mol ΔH = 243 kj/mol ΔH = -349 kj/mol ΔH = kj/mol (a) 479 kj/mol (b) -479 kj/mol (c) -807 kj/mol (d) -828 kj/mol (e) 828 kj./mol 34. Calcium crystallizes in a face-centered cubic (FCC) lattice. What is calcium s coordination number? (a) 1 (b) 2 (c) 4 (d) 8 (e) 12 9 of 12

10 35. Carbon uses what type of hybrid orbitals in ClCN? (a) sp (b) sp 2 (c) sp 3 d (d) sp 3 d 2 (e) sp How many sigma and pi bonds, respectively, are in the molecule below: (a) 16, 1 (b) 16, 0 (c) 15, 1 (d) 14, 1 (e) 15, 0 CH3CH2CHCHCH3 10 of 12

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Name (printed): Signature:

CHEM Lab Section Number: Name (printed): Signature: This exam consists of 36 questions all of equal value for a total of 225 points. Make sure that your test has all of the pages. Please read each problem