CHEM 115 Example Test 2 1 When 2 61 g of solid Na2CO3 is dissolved in sufficient water to make 250 mL of solution the concentration of Na2CO3 is A 0 0246 M B 10 4 M C 0 205 M D 0 0985 M E 0 141 M 2 Phosphine an extremely poisonous and highly reactive gas will react with oxygen to form tetraphosphorus decaoxide and water PH3 g O2 g P4O10 s H2O g unbalanced Calculate the mass of P4O10 s formed when 225 g of PH3 reacts with excess oxygen A 1880 g B 940 g C 900 g D 470 g E 56 3 g 3 Ammonia will react with fluorine to produce dinitrogen tetrafluoride and hydrogen fluoride used in production of aluminum in uranium processing and in frosting of light bulbs 2NH3 g 5F2 g N2F4 g 6HF g How many moles of NH3 are needed to react completely with 13 6 mol of F2 A 34 0 mol B 27 2 mol C 6 80 mol D 5 44 mol E 2 27 mol 4 Tetraphosphorus hexaoxide phosphorus with oxygen gas P4 s 3O2 g P4O6 s If a mixture of 75 3 g of phosphorus and 38 7 g of oxygen produce 43 3 g of P4O6 what is the percent yield for the reaction A 57 5 B 48 8 C 38 0 D 32 4 E 16 3 219 9 g mol is formed by the reaction of 5 In the following reaction what ions if any are spectator ions Pb NO3 2 aq 2NaCl aq PbCl2 s 2NaNO3 aq A Pb2 aq Cl aq B Na aq NO3 C Pb2 aq NO3 aq aq D Na aq Cl aq E There are no spectator ions 101 96 g mol 26 98 g mol and 117 65 g of oxygen 6 Aluminum oxide used as an adsorbent or a catalyst for organic reactions forms when aluminum reacts with oxygen 4Al s 3O2 g 2Al2O3 s A mixture of 82 49 g of aluminum 32 00 g mol is allowed to react What mass of aluminum oxide can be formed A 155 8 g B 200 2 g C 249 9 g D 311 7 g E 374 9 g 7 As in the question above aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent desiccant or catalyst for organic reactions 4Al s 3O2 g 2Al2O3 s A mixture of 82 49 g of aluminum 32 00 g mol is allowed to react Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete A Oxygen is the limiting reactant 19 81 g of aluminum remain B Oxygen is the limiting reactant 35 16 g of aluminum remain C Aluminum is the limiting reactant 16 70 g of oxygen remain D Aluminum is the limiting reactant 35 16 g of oxygen remain E Aluminum is the limiting reactant 44 24 g of oxygen remain 26 98 g mol and 117 65 g of oxygen 8 An acid A B C donates electrons in an electron transfer reaction D donates protons in a proton transfer reaction E does none of the above produces hydroxide ions when dissolved in water changes the color of phenolphthalein indicator from colorless to pink 9 Magnesium carbonate MgCO3 is insoluble Identify the spectator ions when aqueous solutions of sodium carbonate and magnesium chloride are combined 2 A Mg2 and CO3 B Na and Cl C Mg2 and Cl D Na and CO3 E None of the above correctly identifies the spectator ions 2 10 Lithium hydroxide is used in alkaline batteries Calculate the molarity of a solution prepared by dissolving 1 495 moles of LiOH in enough water to give a final volume of 750 mL A 1 99 M B 1 50 M C 1 12 M D 0 502 M E 0 00199 M 11 Which one of the following ionic compounds is insoluble in water A Na3PO4 B AgNO3 C NaCl D CaCO3 E MgCl2 12 Sodium chlorate is used as an oxidizer in the manufacture of dyes explosives and matches Calculate the mass of solute needed to prepare 1 575 L of 0 00250 M NaClO3 A 419 g B 169 g C 0 419 g D 0 169 g E 0 00394 g 13 How many mL of concentrated nitric acid HNO3 16 0 M should be diluted with water in order to make 2 00 L of 2 00 M solution A 32 0 mL B 62 5 mL C 125 mL D 250 mL E 500 mL 14 In the following reaction what is the oxidation number of sulfur on the reactant side of the equation 2Al s 3H2SO4 aq Al2 SO4 3 aq 3H2 g 106 45 g mol A 6 B 4 C 0 2 D E 5 15 Aqueous potassium iodate KIO3 and potassium iodide KI react in the presence of dilute hydrochloric acid as shown below KIO3 aq 5KI aq 6HCl aq 3I2 aq 6KCl aq 3H2O l What mass of iodine I2 is formed when 50 0 mL of 0 020 M KIO3 solution reacts with an excess of KI and HCl A 0 13 g I2 B 0 25 g I2 C 0 38 g I2 D 0 76 g I2 E none of the above 16 Select the precipitate that forms when the following reactants are mixed Na2CO3 aq BaCl2 aq A Ba2CO3 B BaCO3 C NaCl D NaCl2 E BaO 17 What is the oxidation number of iodine in I2 1 0 A B C 1 D 7 E None of the above is the correct oxidation number 18 Select the net ionic equation for the reaction between lithium hydroxide and hydrobromic acid LiOH aq HBr aq H2O l LiBr aq LiOH aq Li aq OH aq A B HBr aq H aq Br aq C H aq OH aq H2O l D Li aq Br aq LiBr aq E Li aq OH aq H aq Br aq H2O l LiBr aq 19 Select the correct name and chemical formula for the precipitate that forms when the following reactants are mixed CoSO4 aq NH4 3PO4 aq A B C cobalt II phosphate Co3 PO4 2 D cobalt III phosphate Co3 PO4 2 E cobalt II phosphate CoPO4 cobalt III phosphate CoPO4 ammonium sulfate NH4 2SO4 20 How many moles of H aq ions are present in 750 mL of 0 65 M hydrochloric acid A 1 2 mol B 0 98 mol C 0 87 mol D 0 65 mol E 0 49 mol