Download CHEM 103 Exam 1 - Determining Empirical Formulas and Calculating Reactions - Prof. Gerald and more Exams Chemistry in PDF only on Docsity! CHEM 103 Exam 1, Dr. Miller NAME_______________ 8:00 A.M., 29 Feb 2000 Section 3 1 _ _ TA's Name_____________ SHOW ALL OF YOUR WORK! If you must continue your work on a problem in another place, please indicate in the space provided for the question where your work is continued. Clearly mark your answers. You may remove the periodic table attached as the last page of the exam if you wish, but do NOT separate the pages of the exam! TOTAL /100 1. (20 pts) Analysis of a compound shows that it is 9.50% sodium, 11.15% aluminum, 26.51 % sulfur, and 52.85% oxygen by mass. Determine the empirical formula of this compound. 4. (24 pts) When a solution containing Ga(NO3) 3 is mixed with a solution containing K2 SO4 , a precipitate of Ca2 (SO4)3 is formed and KNO3 remains in solution. How much Ga2 (SO4) 3 is formed when a solution containing 24.70 g of Ga(NO3) 3 is mixed with a solution containing 25.35 g of K2SO4 ? Please give your answer in grams. 5. (16 pts) Jan makes 10.04 g of the insoluble salt Fe2 S 3 by adding a solution containing 25.00 g of Fe(NO3)3 to a solution containing excess Na2 S. Calculate the percent yield that Jan achieved in this synthesis of Fe2 S 3 . PERIODIC TABLE 1 1 3 Li 6.94 11 Na 23.0 19 K 39.1 37 Rb 85.5 55 Cs 132.9 87 Fr (223) 4 Be 9.01 12 Mg 24.3 20 Ca 40.1 38 Sr 87.6 56 Ba 137.3 88 Ra (226) 21 Sc 45.0 39 Y 88.9 57 La 138.9 89 Ac (227) 22 Ti 47.9 40 Zr 91.2 72 Hf 178.5 104 Rf (259) 23 V 50.9 41 Nb 92.9 73 Ta 180.9 105 Db 24 Cr 52.0 42 Mo 95.9 74 w 183.9 106 Sg 25 Mn 54.9 43 Tc (97) 75 Re 186.2 107 Bh 26 Fe 55.8 44 Ru 101.1 76 Os 190.2 108 Hs 1 H 1.008 27 Co 58.9 45 Rh 102.9 77 Ir 192.2 109 Mt 28 Ni 58.7 46 Pd 106.4 78 Pt 195.1 29 Cu 63.5 47 Ag 107.9 79 Au 197.0 30 Zn 65.4 48 Cd 112.4 80 Hg 200.6 5 B 10.8 13 Al 27.0 31 Ga 69.7 49 In 114.8 81 Tl 204.4 6 c 12.01 14 Si 28.1 32 Ge 72.6 50 Sn 118.7 82 Pb 207.2 7 N 14.01 15 P 31.0 33 As 74.9 51 Sb 121.8 83 Bi 209.0 8 O 16.00 16 S 32.1 34 Se 79.0 52 Te 127.6 84 Po 209 1 1« ] ( 3 I 7 t 12 { ^ (2 9 F 5.0 17 :i 5.5 is &r 9.9 53 I 6.9 35 U 10) 2 He 4.00 10 Ne 20.2 18 Ar 39.9 36 Kr 83.8 54 Xe 131.3 86 Rn (222) 58 Ce 140.1 59 Pr 140.9 60 Nd 144.2 61 Pm (147) 62 Sm 150.4 63 Eu 152.0 64 Gd 157.3 65 Tb 158.9 66 Dy 162.5 67 Ho 164.9 68 Er 167.3 69 Tm 168.9 70 Yb 173.0 71 Lu 175.0 90 Th 232.0 91 Pa (231) 92 U 238.0 93 Np (237) 94 Pu (244) 95 Am (243) 96 Cm (248) 97 Bk (247) 98 Cf (251) 99 Es (254) 100 Fm (257) 101 Md (258) 102 No (255) 103 Lr (257)
