Chem 135 Exam 1 PDF

CHEM 135 – EXAM 1 – Dr. Vedernikov Full Name: _________________________________ First letter of your Last Name: Please PRINT Lecture time: ** am Discussion Section day (circle one): M W Discussion section time (circle one): 10:00am 12:00pm 1...

CHEM 135 – EXAM 1 – Dr. Vedernikov Full Name: _________________________________ First letter of your Last Name: Please PRINT Lecture time: ** am Discussion Section day (circle one): M W Discussion section time (circle one): 10:00am 12:00pm 1:00pm 2:00pm “I pledge on my honor that I have not given or received any unauthorized assistance on this examination” Signature Date This exam contains 6 pages in total including this title page:  14 questions on pages 2-4 (do NOT unstaple these pages and the title page)  some physical constants on page 5 and  the Periodic Table of the Elements on page 6 (you may detach it). Check if you have all of that before you begin. You may use any blank pages as a scratch paper. Put your answers ONLY in the space provided. Examination rules:  You may not begin until everyone has an exam  When time is called, put your pencil down and remain in your desk  After all exams have been collected, you will be dismissed Question 1: _____/6 pts Question 8: ____/6 pts Question 2: _____/6 pts Question 9: ____/6 pts Question 3: _____/8 pts Question 10: ____/6 pts Question 4: _____/6 pts Question 11: ____/8 pts Question 5: ____/6 pts Question 12: ____/6 pts Question 6: ____/10 pts Question 13: ____/8 pts Question 7: ____/10 pts Question 14: ____/8 pts TOTAL POINTS: _________/100 When performing calculations, pay attention to the number of significant figures in your answer! 1. (6 pts) Consider the following pure substances at the temperature of 25 oC and ambient pressure listed in the Table below. Classify each of them as a compound, a covalent substance, a metal, a non-metal. Check all boxes that apply. BeF2 Bi SiO2 O3 He graphene Compound Covalent substance Metal Non-metal 2. (6 pts) a) Indicate the number of electrons, protons and neutrons in one atom of fluorine-18: # of protons: _________ # of electrons: ________ # of neutrons: ___ b) Given the number of subatomic particles of each kind in a monoatomic species, write its formula in the format AXn where n is the charge (if different from 0): # of protons: 23 # of electrons: 21 # of neutrons: 30 Answer: __________ 3. (8 pts) How many moles of hydrogen atoms are there in 1.00 g of NH3BH3 (molecular mass 30.87 amu)? Show your work: Answer: ____________ moles H 4. (6 pts) Use definition of the mole and the atomic mass unit (amu) as well as physical constants provided on p. 6 and calculate the mass in grams of 1 atomic mass unit (amu). Use three significant figures. Show your work: Answer: 1 amu = ____________ g 5. (6 pts) A 10.0 g sample of an element contains 4.39×1022 atoms. Identify the element and show your work: Answer: __________ 2 6. (10 pts) Consider substances below at 25 oC and normal pressure. List formulas of ions as requested. If no ions are present, put N/A: a) Ions present in Na2HPO4(s): __________________________ b) Major monoatomic cations derived from lead: __________________________ c) Ions present in PI3(s): __________________________ d) Ions present in Ti2O3(s): __________________________ e) Major monoatomic anions derived from sulfur: __________________________ 7. (10 pts) Provide a systematic name or a chemical formula for the following pure substances: a) barium peroxide __________________ b) ____________________________________________________ NaClO c) ____________________________________________________ CuF2 d) ____________________________________________________ GeCl4 e) aluminum hydrogen sulfate ___________________ 8. (6 pts) The first ionization energy of a gaseous atom is 1402 kJ/mol. Calculate the maximum wavelength in nm of the electromagnetic wave that can ionize this atom. Show your work: Wavelength: ____________ nm 9. (6 pts) Provide a designation (e.g., 4dxy) for the atomic orbitals with the given set of quantum numbers. If some combinations are meaningless, put N/A. a) n = 3, l = 0, with no nodal planes Answer: _______ ; b) n = 2, l = 1, with a nodal plane x = 0 Answer: _______ ; c) n = 2, l = 2, with two nodal planes, x = 0 and y = 0 Answer: _______. 3 10. (6 pts) Consider drawings of the atomic orbitals below. White and dark colors represent areas with different sign of the wavefunction. For each of the orbitals provide a designation, e.g., 5p; no subscript part is needed: a) (a cross-section): Answer: _____ ; b) (a cross-section): Answer: _____. 11. (8 pts) Provide the full orbital diagram for the Ge2+ ion in its ground-state: 12. (6 pts) a) Indicate the number of unpaired electrons in the following species in their ground state configuration: i) Ca, [Ar]4s2: ____ ; ii) Cr2+, [Ar]3d4: ____ ; iii) S, [Ne]3s23p4: ____. b) Indicate the number of the valence electrons in the following species: i) Al _____; ii) Pd _____; iii) Xe _____. 13. (8 pts) Arrange the following species according to their increasing a) atomic radius: Al, Ne, Ca: (smallest) ___________________________________ (largest) b) ionic radius: I-, Br-, Rb+: (smallest) ___________________________________ (largest) c) electron affinity: Ne, H, F: (most negative) __________________________ (least negative) d) ionization energy: Li, N, Si: (lowest) ___________________________________ (highest) 14. (8 pts) Alizarin is a natural pigment known to painters as Alizarin crimson. Alizarin contains 70.00% C, 3.36% H and 26.64% O by mass. Determine the empirical formula of alizarin. Show your work: Empirical formula: ___________ 4  Some Physical Constants and Formulas Planck constant, h: 6.626×10-34 J×s Speed of light, c: 2.998×108 m×s-1 Avogadro number, NA: 1 mole = 6.022×1023 particles / mol c =  E = h  (natural _ isotope _ abundance _ in _ %)(isotope _ atomic _ mass) all _ isotopes Atomic mass = 100% Energy of light emitted or absorbed by the hydrogen atom due to an electron transition from level ninitial to nfinal : ଵ ଵ E = Efinal – Einitial = െ2.180 ൈ 10ିଵ଼ ൬௡మ െ మ ௡೔೙೔೟೔ೌ೗ ൰J ೑೔೙ೌ೗ You can use this area as scratch paper: 5  Periodic Table of the Elements 1 18 1 2 1 H He 1.008 4.003 2 13 14 15 16 17 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 13 14 15 16 17 18 3 Na Mg Al Si P S Cl Ar 22.99 24.31 26.98 28.09 30.98 32.07 35.45 39.95 3 4 5 6 7 8 9 10 11 12 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.10 40.08 44.96 47.87 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.41 69.72 72.61 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.47 87.62 88.91 91.22 92.91 95.94 (97.9) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 57-71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La-Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 132.9 137.3 178.5 180.9 183.8 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 (209.0) (210.0) (222.0) 87 88 89-103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 7 Fr Ra Ac-Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og (223.0) (226.0) (261.1) (262.1) (263.1) (262.1) (265) (266) (271) (272) (285) (284) (289) (288) (292) (294) (294) 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 6 Lanthanides La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 138.9 140.1 140.9 144.2 (144.9) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 174.0 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 7 Actinides Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr (227.0) 232.0 231.0 238.0 (237.1) (244.1) (243.1) (247.1) (247.1) (251.1) (252.1) (257.1) (258.1) (259.1) (260.1) 3