1CHEM 107 (Spring-2005) Exam 2 (100 pts) Name: ------------------------------------------------------------------------, Clid # ------------------------------ LAST NAME, First (Circle the alphabet segment of your LAST NAME): A, B C-G H-N O-S T-Z Please answer the following questions: Part I: Multiple Choices (52 pts: 13 @ 4 pts each + 4 pts bonus). Circle the ONE best answer: 1. The number of ions formed when Na3PO4 is dissolved in water is: a) 4 b) 3 c) 2 d) 8 2. For the reaction: a Al (s) + b H2SO4 (aq) c Al2(SO4)3 (aq) + d H2 (g) The corresponding order for the coefficients a, b, c and d is: a) 2, 6, 2 and 3 b) 2, 3, 2 and 3 c) 4, 6, 4 and 6 d) 2, 3, 2 and 6 3. In the above reaction, the spectator ion(s) are: a) H+ and SO42- b) Al3+ and H+ c) only SO42- d) Al3+ and H+ 4. Which of the following salts are expected to be soluble in water? a) BaSO4 b) ZnS c) Ca(OH)2 d) K3PO4 5. Two solutions, A and B, are labeled “0.10 M CaCl2” and “0.20 M CaCl2”, respectively. Both solutions contain the same number of moles of CaCl2. If solution A has a volume of 50 mL. What is the volume of solution B? a) 100 mL b) 50 mL c) 25 mL d) no answer was given 6. Aluminum and oxygen react according to the following equation: 4 Al (s) + 3 O2 (g) 2 Al2O3 (s) What mass of Al2O3 (102.0 g/mol), in grams, can be made by reacting 4.6 g of Al with excess oxygen? a) 1.2 g b) 17 g c) 8.7 g d) 35 g 7. Which of the following is classified as a weak acid? a) HBr b) NH3 c) HNO2 d) NaC2H3O2 (sodium acetate)28. Calculate the molarity of Cl- in 245.0 mL of a solution containing 23.4 g BaCl2 (MM = 208.22 g/mol)? a) 0.112 b) 0.0275 c) 0.459 d) no answer was given 9. Which of the following is a weak electrolyte: a) Potassium chloride (KCl) b) Hydrobromic acid (HBr) c) Nitrous acid (HNO2) d) Nitric acid (HNO3) 10. What mass of KOH, in grams, is required to prepare 500. mL of 2.35 M KOH? a) 65.9 b) 1.18 c) 20.9 d) 14.0 11. The oxidation states of sulfur in H2S and S2O32- are: a) -2 and +4, respectively b) -2 and +2, respectively c) -2 and +3, respectively d) +2 and +2, respectively 12. In a titration, 23.25 mL of 0.105 M NaOH was needed to react with 21.45 mL of HCl. What is the molarity of the acid? a) 2.44 M b) 0.105 M c) 0.114 M d) no answer was given 13. Which reaction will not produce a precipitate from aqueous solutions? a) FeSO4 + Ba(OH)2 b) Pb(NO3)2 + Na2CO3 c) ZnCl2 + (NH4)2S d) NaBr + Al2(SO4)3 14. Which of the following equations DO NOT represent an oxidation? a) SO2 SO3 b) Mg Mg2+ c) MnO2Mn2+ d) 2 Br- Br23Part II. Equations and formulas (28 pts) Write balanced chemical equation for each of the following. Including physical states as (s, l, g aq) (Use the periodic chart for charges on each ion and reference sheet). Please write N. R. if there is no reaction. 1. (6 pts) Write the balanced chemical equation for the reaction, if any occurs between aqueous solutions of FeCl3 and NaNO3 (write N.R. if they do not react; no chemical equation) 2. (10 pts) Write the chemical equation and the net ionic equation for the reaction between aqueous solutions of Na2SO4 and Ba(OH)2 and then identify the spectator ion(s) 3. (12 pts) Write the balanced chemical equation for the following reaction occurring in an acidic solution: I2 + OCl- IO3- + Cl- (acidic solution) Chemical equation: Chemical equation: Net ionic equation: Spectator ion(s):4Part III. Calculations (20 pts) Show all work for full credit. Please express all answers with the proper units and correct number of significant figures. 1. Aluminum and bromine react vigorously as represented by the following balanced equation: Al (s) + 3 Br2 (l) 2 AlBr3 (s) If 5.0 g of aluminum was allowed to react with 22 g of bromine: a) Which reagent will be totally consumed (limiting reactant)? b) What is the maximum amount of product, in grams, that can be formed? a) If you perform the experiment and isolate 18 g of AlBr3, what is the percent yield? c) Percent yield 75% a) Limiting reactant b) Theoretical yield of CO 24 g5 Exam 2 – Spring 2005 You will have 55 minutes to complete this exam. The exam has 5 pages plus the Periodic Table and Reference page. When you are told to do so, tear off the Periodic Table cover sheet and use as required during the exam. 1 1 H 1.01 Periodic Table of the Elements 2 He 4.00 2 3 Li 6.94 4 Be 9.01 5 B 10.816 C 12.01 7 N 14.01 8 O 16.009 F 19.0010 Ne 20.18 3 11 Na 22.99 12 Mg 24.30 13 Al 26.9814 Si 28.08 15 P 30.97 16 S 32.0617 Cl 35.4518 Ar 39.95 4 19 K 39.1 20 Ca 40.08 21 Sc 44.96 22 Ti 47.88 23 V 50.94 24 Cr 52.00 25 Mn54.9426 Fe 55.8527 Co 58.9328 Ni 58.6929 Cu 63.5530 Zn 65.3831 Ga 69.7232 Ge 72.59 33 As 74.92 34 Se 78.9635 Br 79.9036 Kr 83.80 5 37 Rb 85.47 38 Sr 87.62 39 Y 88.91 40 Zr 91.22 41 Nb 92.91 42 Mo 95.94 43 Tc (98) 44 Ru 101.145 Rh 102.946 Pd 106.447 Ag 107.948 Cd 112.449 In 114.850 Sn 118.7 51 Sb 121.8 52 Te 127.653 I 126.954 Xe 131.1 6 55 Cs 132.9 56 Ba 137.3 57 La 138.9 72 Hf 178.5 73 Ta 181.0 74 W 183.8 75 Re 186.276 Os 190.277 Ir 192.278 Pt 195.179 Au 197.080 Hg 200.681 Tl 204.482 Pb 207.2 83 Bi 209.0 84 Po (209) 85 At (210) 86 Rn (222) 7 87 Fr (223) 88 Ra 226.0 89 Ac 227.0 104 Rf (261) 105 Db (262) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Mt (266) 110 Uun(269) 111 Uuu(272) 112 Uub(277) 58 Ce 140.1 59 Pr 140.9 60 Nd 144.2 61 Pm(145) 62 Sm 150.463 Eu 152.064 Gd 157.265 Tb 158.966 Dy 162.567 Ho 164.968 Er 167.3 69 Tm 168.9 70 Yb 173.071 Lu 175.0 90 Th 232.0 91 Pa 231.0 92 U 238.0 93 Np 237.094 Pu (244) 95 Am(243) 96 Cm(247) 97 Bk (247) 98 Cf (251) 99 Es (252) 100 Fm (257) 101 Md (258) 102 No