Answer Key Chem 10113, Quiz 3 September 16, 2015 IA VIIIA (1) (18) 1 IIA IIIA IVA VA VIA VIIA He 1.0080 (2) (13) (14) (15) (16) (17) 4.0026 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 6.9410 9.0122 10.811 12.011 14.007 15.999 18.998 20.179 11 12 13 14 15 16 17 18 Na 22.990 2 3 2 H 1 4 IVB VB VIB 24.305 (3) (4) (5) (6) VIIB . . . . . . . . . . VIIIB . . . . . . . . .IB . (7) (8) (9) (10) (11) IIB Al Si P S Cl Ar (12) 26.982 28.086 30.974 32.066 35.453 39.948 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 83.800 39.098 5 Mg IIIB 69.723 72.610 74.922 78.960 79.904 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 131.29 85.468 6 114.82 118.71 121.75 127.60 126.90 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 204.38 207.20 208.98 208.98 209.99 222.02 132.91 87 Fr 7 40.078 44.956 47.880 50.942 51.996 54.938 55.847 58.933 58.690 63.546 65.380 223.02 87.620 88.906 91.224 92.906 95.940 98.907 101.07 102.91 106.42 107.87 112.41 137.33 138.91 178.49 180.95 183.85 186.21 190.20 192.22 195.09 196.97 200.59 88 89 Ra Ac 104 Unq 105 Unp 106 Unh 107 Uns 226.03 227.03 261.11 262.11 263.12 262.12 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 164.93 167.26 168.93 173.04 174.97 140.12 140.91 144.24 145.91 150.36 151.97 157.25 158.93 162.50 90 91 92 93 94 Th Pa U Np Pu 95 96 Am Cm 97 98 99 100 101 102 103 Bk Cf Es Fm Md No Lr 252.08 257.10 258.10 259.10 260.11 232.04 231.04 238.03 237.05 244.06 243.06 247.07 247.07 242.06 1. SHOW ALL WORK. A certain organic amine is found to have the following percentage composition by mass: 60.83 % C, 8.75 % H, and 30.41 % N. Determine the empirical formula of this compound. (6 points) (60.83 g C) (1 mole C / 12.01 g) = 5.065 mole C (8.75 g H) (1 mole H / 1.008 g) = 8.681 mole H (30.41 g N) (1 mole N / 14.007 g) = 2.171 mole N C5.065 H8.681 N2.171 = C5.065/2.171 H8.681/2.171 N2.171/2.171 = C2.33 H4.00 N 2. (2 points) (x 3) = C7H12N3 Write a complete, balanced chemical equation for the combustion of ethanol, C2H5OH. C2H5OH + 3 O2 → 2 CO2 + 3 H2O 3. Complete the following table of compound names and formulas. (9 points) Formula Name As2S5 diarsenic pentasulfide Sn(S2O3)2 tin(IV) thiosulfate HBrO4(aq) perbromic acid . 4. Mg3(PO4)2 4H2O magnesium phosphate tetrahydrate XeO3 xenon trioxide Cs2Cr2O7 cesium dichromate H2Se(aq) hydroselenic acid Al2(CO3)3 aluminum carbonate Hg(CN)2 mercury(II) cyanide Write a complete, balanced chemical equation for the production of barium nitrite by a neutralization reaction. (2 points) Ba(OH)2 5. + 2 HNO2 → Ba(NO2)2 + 2 H2O SHOW ALL WORK. The sulfide of a certain metal is thought to have the formula M2S5. A 2.500 g sample of this compound is found to contain 0.04767 mole S. Identify the metal M by determining its atomic mass. (6 points) mass of S = (0.04767 mole S) (32.066 g / mole) = 1.529 g S mass of M = 2.500 g - 1.529 g = 0.9714 g M moles of M = (0.04767 mole S) (2 mole M / 5 mole S) = 0.01907 mole M molar mass of M (i.e., g/mole) = 0.9714 g / 0.01907 mole = 50.94 g/mole ∴ M = V (vanadium)