Chem 200 Fall16-Exam 2-B KEY.pdf - CHEM 200 Fall 2016 CHEM Exam 2-B Lab Section Number Name(printed Signature This exam consists of 36 questions all of

Chem 200 Fall16-Exam 2-B KEY.pdf - CHEM 200 Fall 2016 CHEM...

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Unformatted text preview: CHEM 200 Fall 2016 CHEM _______ Exam 2-B November 25, 2016 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 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 Please mark your answers on the scantron sheet using a #2 pencil and also mark your answers on the exam itself. Mark the test form version “002” on your scantron. 1. Calculate heat when 28.6 g of water is heated from 22.0 °C to 78.3 °C. (a) (b) (c) (d) (e) 0.385 kJ 1.61 kJ 6.74 kJ 9.37 kJ 1.61 x 103 kJ 2. Which of the following frequencies of electromagnetic radiation has the shortest wavelength? (a) (b) (c) (d) (e) 1 kHz 1 mHz 1 daHz 1 GHz 1 MHz 3. The AM station KBOR plays your favorite music from the 80's and 90's at 1290 kHz. Find the wavelength of these waves. (a) (b) (c) (d) (e) 4.30 x 10-2 m 0.144 m 6.94 m 232 m 2.32 nm 4. A radio wave has a frequency of 8.6 x 108 Hz. What is the energy of one photon of this radiation? (a) (b) (c) (d) (e) 7.7 x 10-43 J 2.3 x 10-34 J 5.7 x 10-25 J 1.7 x 10-16 J 1.2 x 10-15 J 5. In a constant-pressure calorimeter, 55.0 mL of 0.320 M Ba(OH)2 added to 55.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 22.89 °C to 27.25 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.18 J/g·°C, respectively),what is ΔH for this reaction per mole of H2O produced? (a) (b) (c) (d) (e) -57.0 kJ/mol 57.0 kJ/mol 114 kJ/mol -144 kJ/mol 143 kJ/mol 2 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 6. If you combine 270.0 mL of water at 25.00 °C and 140.0 mL of water at 95.00 °C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water. (a) (b) (c) (d) (e) 53.42 °C 48.90 °C 46.74 °C 36.23 °C 23.67 °C 7. If a system has 345 J of work done to it, and releases 5.26 kJ of heat into its surroundings, what is the change in internal energy of the system? (a) (b) (c) (d) (e) 5.61 x 103 J 4.92 x 103 J -4.92 x 103 J 350. J -350. J 8. When 1356 J of heat energy is added to 32.5 g of hexane, C6H14, the temperature increases by 14.0 °C. Calculate the molar heat capacity of C6H14 (a) (b) (c) (d) (e) 2.98 J/mol·°C 54.6 J/mol·°C 113 J/mol·°C 257 J/mol·°C 287 J/mol·°C 9. Platinum, which is widely used as a catalyst, has a work function (the minimum energy needed to eject an electron from the metal surface) of 9.05 x 10¯19 J. What is the longest wavelength of light which will cause electrons to be emitted? (a) (b) (c) (d) (e) 2.20 x 10-7 m 4.55 x 10-6 m 5.65 x 102 m 1.37 x 1015 m 1.22 x 106 m 10. Calculate the frequency of a photon absorbed when the hydrogen atom undergoes a transition from n1 = 2 to n2 = 4. (a) (b) (c) (d) (e) 2.056 x 106 Hz 2.742 x 106 Hz 6.169 x 1014 Hz 8.226 x 1014 Hz 3.234 x 1015 Hz 11. Which scenario will result in the greatest decrease in energy for the system? (a) (b) (c) (d) (e) The system releases 234 cal of heat and has 430 J of work done on it. The system gains 904 J of heat and does 23.9 cal of work. The system does 321 cal of work and loses 2.34 kJ of heat. The system has 1.09 kJ of work done to it and loses 892 cal of heat. The system gains 1000. cal of heat and does 4.184 kJ of work. 3 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 12. Solid strontium chloride (SrCl2) is added to an aqueous solution of silver nitrate, precipitating silver chloride. Given that the standard enthalpy of reaction (ΔHºrxn) is -182.97 kJ determine the standard heat of formation (ΔHºf) for silver ions (Ag+(aq)). SrCl2(s) + 2Ag+(aq) + 2NO3-(aq) → Sr2+(aq) + 2AgCl(s) + 2NO3-(aq) Species SrCl2(s) Sr2+(aq) Ag+(s) AgCl(s) NO3-(aq) Cl-(aq) ΔHºf (kJ/mol) -828.4 -545.51 312.47 -127.03 -206.57 -167.46 (a) (b) (c) (d) (e) -719.5 kJ/mol 105.9 kJ/mol -100.67 kJ/mol 312.47 kJ/mol -348.47 kJ/mol 13. Calculate the enthalpy change for the reaction NO(g) + O(g) → NO2(g) from the following data: NO(g) + O3(g) → NO2(g) + O2(g) ΔH = -198.9 kJ
 O3(g) → 3/2O2(g) ΔH = -142.3 kJ
 O2(g) → 2O(g) ΔH = 495.0 kJ (a) (b) (c) (d) (e) -551.6 kJ -304.1 kJ 190.9 kJ 153.8 kJ 438.4 kJ 14. Given the reaction below, and an excess of O2(g) how many grams of SO2(g) would be needed for the reaction to release 283.4 kJ of heat? 
 2SO2(g) + O2(g) → 2SO3(g) (a) (b) (c) (d) (e) ∆H = -198.4 kJ Impossible, this reaction is endothermic. 45.76 g 128.1 g 183.0 g 112.1 g 15. Which is not an example of the wave-particle duality; where a particle may act like a wave, or a wave may act like a particle? (a) (b) (c) (d) (e) The diffraction patterns of electrons passes through aluminum crystals. Blackbody radiation. The refraction of a beam of light passing from air into water. The photoelectric effect. The line spectrum for the emission of light from a hydrogen atom. 4 of 12 Fall 2015 Exam 2-A CHEM 200 Fall 2016 October 17, 2015 Exam 2-B November 25, 2016 answers on the scantron sheet using a #2 pencil and also mark your answers 16. Which one of the following equations represents the formation reaction of CH3OH(l)? (a) C(g) + 2H2(g) + ½O2(g) → CH3OH(l) C(s) + 4H(g) + O(g) → CH3OH(l) m version on your(b) scantron. (c) C(graphite) + 4H(g) + O(g) → CH3OH(l) (d) C(diamond) + 4H(g) + O(g) → CH3OH(l) laser that has a wavelength of 405 nm. Calculate (e) C(graphite) + 2H2(g) + ½O2(g) → CH3OH(l) are read with a photons from this type of laser. 
 05 J 0−6 J 0−19 J 04 J
 the energy 17. A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 8.45 x 104 g? (1 km = 0.62137 mi) (a) (b) (c) (d) (e) 7.31 x 10¯37 m 3.26 x 10¯37 m 5.08 x 10¯30 m 1.34 x 10¯30 m 1.54 x 10¯30 m −28 th a mass of 18. 9.11×10 theuncertainty nucleus of a hydrogen atom. Ain the speed of an According g to is theorbiting Heisenberg principle, if the uncertainty 3 m/s, theto determines the position electron within ±1.63 nm. The velocity of (mass the of an electron isof 3.5the x 10 uncertainty in its position (in m) is at least: 6 m/s. electron is 9.11 x 10is-28the g) uncertainty in the velocity of the asured as 6.39×10 What (a) 1.6 x 10¯8 m (b) 6.6 x 10¯8 m (c) 17 m (d) 66 m (e) m the75 velocity. s s s no uncertainty in 04 m/s 19. Consider the set of isoelectronic atoms and ions: A+, B2—, C—, D3—, E3+. Which 04 m/s arrangement of relative radii is correct? E3+ < A+< the C— <direction B2— < D3—of spin for an electron orbiting an m number is used to(a)describe (b) (c) (d) (e) A+ < E3+ < C— < B2— < D3— D3— < B2— < C— < A+ < E3+ C— < B2— < D3— < E3+ < A+ A+ < E3+ < D3— < B2— < C— 20. Which of the following elements has the largest fourth ionization energy (IE4)? (a) B (b) Al (c) Ga (d) In initially (e) Tl of copper metal is at 100.0°C. It is dropped into a coffee cup ntaining 50.0 g of water at a temperature of 20.0°C. After stirring, the final both copper21. and water is 25.0°C. Assuming nohas heat losses, and that the Which molecule, of those listed, below a <120º angle between atoms? apacity of water is 4.18 J/g•K, what is the heat capacity of the copper in J/K? 
 K K K (a) (b) (c) (d) (e) ClF3 XeO2F2 NH4+ XeOF4 XeF4 f these choices is correct.
 5 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 22. What is the average bond order for the phosphate ion? (a) (b) (c) (d) (e) 1 1.25 1.5 1.75 2 23. From the list of molecules below, identify those which are polar molecules. Mark all correct answers. (a) (b) (c) (d) (e) BrF3 BF3 NH4+ XeF2 CH2O 24. Which of the molecules below would have the largest magnitude lattice energy? (a) Cl2 (b) KCl (c) LiCl (d) MgCl2 (e) BaCl2 25. An atom of element number 35 (Br) is n its ground electronic state. Which one of the following set of quantum number could not apply to any of its electrons? (a) (b) (c) (d) (e) n= 4 ml= -2 n= 3 l=2 n= 4 l= 0 ms = +1/2 n= 1 l= 0 n= 5 l= 2 26. Identify the element from Period 4, which has the successive ionization energies tabulated below: Ionization 1st 2nd 3rd 4th 5th 6th 7th 8th Energy (kJ/mol) 1314 3389 5298 7471 10,992 13,329 71,345 84,087 (a) (b) (c) (d) (e) K Ga Ge Se Br 6 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 27. The shape of an atomic orbital is associated with: (a) (b) (c) (d) (e) the principal quantum number (n). the angular momentum quantum number (l). the magnetic quantum number (ml). the spin quantum number (ms). the magnetic and spin quantum numbers, together. 28. Which of the following is a correct set of quantum numbers for an electron in a 5f orbital? (a) (b) (c) (d) (e) n = 5, l = 3, ml = +1 n = 5, l = 2, ml = +3 n = 4, l = 3, ml = 0 n = 4, l = 2, ml = +1 n = 5, l = 4, ml = 3 29. Select the correct electron configuration for Ag (Z =47). (a) [Kr]5s24d9 (b) [Kr]5s14d10 (c) [Kr]5s25p64d3 (d) [Kr]5s14p14d9 (e) [Kr]5s25p9 30. Which of the following electrons configurations is impossible? There is only one correct answer. (a) (b) (c) (d) (e) 1s22s22p63s23p4 1s22s22p53s13p4 1s22s22p63s23p64s23d10 1s22s22p63s33p4 1s12s22p63s23p4 31. Which of the following elements is the least electronegative? (a) Si (b) Se (c) S (d) Sc CHEM 200/202 (e) Sr Fall 2013 Name__________________________________ Exam 3 November 16, 2013 Lab Sect. No.__________ 32. Identify the elements whose Lewis symbol has been properly depicted. Mark all correct 6. Identify the elements whose Lewis symbol has been properly depicted. Mark all correct answers. answers.
 
 
 
 ! 7. Which of bonds below is the strongest?! (a) C−H! (b) C=O! (c) C=C! (d) C−N! (e) C−F
 ! 7 of 12 8. For the reaction below, determine ∆Hrxn (in kJ) based on the provided bond energies:
 H−C 413; C−C 347; C=C 614; C−Br 276; H−Br 363 (all in kJ/mol)! (a) 288 kJ! (d) Linear! (c) C=C! (e) Trigonal pyramidal
 (d) C−N! From the of molecules below identify the molecule whose central November atom has a formal CHEM 200list Fall 2016 Exam 2-B (e)13. C−F
 25, 2016 charge of -1.! (a)determine NO2! 8. For the reaction below, ∆Hrxn (in kJ) based on the provided bond energies:
 reaction below, determine the Hrxn (in kJ) based on the provided bond energies: 33. For the + (b) NH ! H−C 413; C−C 347; C=C4 614; C−Br 276; H−Br 363 (all in kJ/mol)! (c) IF2-! (a) 288 kJ! (d) SO42-! (b) 555 kJ! (e) CO32-
 (c) 59 kJ! (d) -555 kJ! the resonance hybrid Lewis structure of carbonate (CO32-) which statement (e)14. -59Considering kJ
 below is correct?! (a) listed The bond length of each bondbond between andoxygen oxygen in the the resonance 9. Which of the molecules below has the smallest ordercarbon between and H—C C—C C=C C—Br H—Br hybrid is longer than a regular C−O bond.! central atom?! (a) CO! Hrxn(b) The bond413 614 276in the resonance 363 length of each 347 bond between carbon and oxygen (kJ/mol) (b) CO2! hybrid is longer than a regular C=O bond.! (c) CO32-! ThekJresonance hybrid Lewis structure is the result of the rotation of the molecule.! (d) SO2! (a)(c)288 555 (b) (d) ThekJlength of the bonds between carbon and oxygen vary continuously in the 2(e) SO4 
 kJ (c) 59resonance hybrid structure.! kJ (d)(e)-555 The bonds between carbon and oxygen in the resonance hybrid are weaker than a 10. Which of the following elements is the least electronegative?! kJ (e) -59 regular C−O bond.
 (a) Si! (b) Se! 34. For the molecule, ClF3, how many lone pairs of electrons are there on the central (c)15. S! Which of the molecules listed below have a central atom that is not obeying the octet rule for chlorine atom? (d) Sc!Lewis structures? Mark all correct answers.! (e) Sr
 (a)(a)0 SO ! ! ! ! ! ! ! ! 2 (b)(b)1 CH2O! 11. For the molecule ClF how many lone pairs of electrons are there on the central chlorine 3, 2 (c)(c) NO2! atom?! (d) 3 (d) BF3! (e) 4 (a) 0! (e) H2O2
 (b) 1! (c) 2!35. What are the formal charges of each of the atoms in the molecule below? (d)16. 3! What are the formal charges of each of the atoms in the molecule below?! , C= =0 0, N, N= = 0 0! (a)(a)OO= =-1-1, C (e) 4
 (b) O = -1 , C = 0 , N = (b) O = -1 , C = 0 , N = +2+2! 0 0! (c)(c)OO= =+1+1, C , C= =0 0, N, N= = O = +1 , C = 0 , N = -2-2! (d) (d) O = +1 , C = 0 , N = = 0 , N = -3-3
 (e)(e)OO= =+2+2, C ,C=0,N= 
 ! ! ! 36. Which of the molecules listed below have a central atom that is an expanded octet for Lewis structures? (a) (b) (c) (d) (e) SO2 CH2O NO2+ BF3 H2O2 8 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 BLANK PAGE 9 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 BLANK PAGE 10 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 BLANK PAGE 11 of 12 CHEM 200 Fall 2016 Exam 2-B November 25, 2016 BLANK PAGE 12 of 12 ...
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