CHEM Lab Section Number: Name (printed): Signature: This exam consists of 36 questions all of equal value for a total of 225 points. Make sure that your test has all of the pages. Please read each problem carefully. There are no intentionally misleading questions; each problem should be taken at its face value. Please mark your answers on the Scantron sheet provided to you and on the actual exam. You will be given a periodic table and an exam information sheet to use during the exam. You may remove it from the exam make it more accessible. You may also use the designated Casio fx-300ms-plus calculator or equivalent non-programmable non-graphing scientific calculator during the exam. Use the back pages of the test as scratch paper. You are not allowed to use any devices capable of accessing the internet, textbooks, notes, or homemade reference sheets during the exam. You may leave if you finish the exam early. Give the exam and the information sheet to your TA and leave quietly without disturbing other students. Before leaving, check that all your answers have been properly entered on the Scantron sheet and the exam and that your name is written on every page of the exam and on the Scantron sheet. All cell phones and electronic devices must be turned off and put away. Please remove all hats and caps. Place your books and all papers out of sight under your seat. If the TA believes that you might be looking at your neighbor s paper, you will be asked to move to a new location. Exam scores will be posted on Blackboard as soon as the grading is complete. Your test will be returned to you in the first lab meeting of next week. If you have any questions regarding the grading of your exam, please notify your TA. The time available for the exam is 120 minutes. Good luck! 1 of 10
Name: Lab Section #: Please mark your answers on the scantron sheet using a #2 pencil and also mark your answers on the exam itself. Mark Test From A on your scantron. 1. Magnesium reacts with iron(iii) chloride to form magnesium chloride and iron by the reaction below (NOTE: the reaction needs to be balanced). A mixture of 41.0 g of magnesium and 175 g of iron(iii) chloride is allowed to react. What mass of magnesium chloride is formed? (a) 154 g (b) 107 g (c) 71.4 g (d) 77.0 g (e) 107 g 2. Perform the following calculation: (a) 1.123 (b) 1.12 (c) 1.10 (d) 1.230 (e) 1.2302 Mg(s) + FeCl3(s) MgCl2(s) + Fe(s) (5.670-0.0467) / (0.0072 + 5.000) 3. Which of the following is NOT a metalloid? (a) Boron (b) Phosphorus (c) Silicon (d) Tellurium (e) Germanium 4. Which of the following would be considered a chemical change? (a) melting wax (b) burning wood in a fire (c) boiling water (d) mixing sand and water (e) carving a piece of wood 2 of 10
5. Which is of the following is an example of a physical change? (a) decomposition of waste (b) digesting food (c) a rusting nail (d) silver forming silver oxide in air (e) ice melting 6. Aluminum oxide forms when aluminum reacts with oxygen by the reaction below (NOTE: the reaction needs to be balanced). A mixture of 82.49 g of aluminum and 117.65 g of oxygen is allowed to react. What mass of aluminum oxide can be formed? (a) 200.2 g (b) 311.7 g (c) 249.9 g (d) 155.9 g (e) 374.9 g Al(s) + O2(g) Al2O3(s) 7. Which of the following is NOT a correct element name-symbol combination? (a) Gold, Au (b) Silver, Ag (c) Antimony, At (d) Lead, Pb (e) Strontium, Sr 8. Which of the following is a weak base? (a) KOH (b) H2SO4 (c) HNO3 (d) NH3 (e) NaOH 9. What is the name of NaH2PO4? (a) Sodium phosphate (b) Sodium hydrogen phosphate (c) Sodium dihydrogen phosphite (d) Sodium hydrogen phosphite (e) Sodium dihydrogen phosphate 3 of 10
10. Determine the formula for chromium(vi) phosphate? (a) CrPO3 (b) CrPO4 (c) Cr(PO4)2 (d) Cr(PO4)3 (e) CrPO2 11. How many neutrons are in lithium-6? (a) 3 (b) 4 (c) 6 (d) 7 (e) 5 12. What is the overall charge of the sulfite ion? (a) 3 (b) 2 (c) -1 (d) -2 (e) -3 13. Which of the following is the acetate ion? (a) CH3CO2 (b) CH3CO3 (c) HCO3 (d) CH3CO3 (e) CO3 2 14. Which of the following is a weak acid? a) HNO3 b) HF c) HI d) H2SO4 e) HBr 15. If each of the pairs of aqueous ionic compounds listed below were to be combined in a solution, which one(s) would result in the formation of a precipitate? a) NaCl and Ca(NO3)2 b) H2SO4 and Ca(OH)2 c) NH4NO3 and KClO4 d) KCH3CO2 and (NH4)2S e) Sr(NO3)2 and RbCl 4 of 10
16. In which of the compound below does the nitrogen atom have an oxidation number of +5? a) N2H4 b) NO2 c) NH3 d) NO e) NaNO3 17. What is the oxidation number of carbon in Na2C2O4? a) +2 b) +3 c) +5 d) 2 e) 3 18. Which of the following has elements that do not have an oxidation number of zero? a) S8(s) b) P4(s) c) Li(s) d) Na(aq) e) Hg(l) 19. How many significant figures are in 0.0000401 kg? a) 7 b) 8 c) 3 d) 1 e) 2 20. Which of the following elements exists as a diatomic molecule in its standard state? (a) Chlorine (b) Sulfur (c) Helium (d) Mercury (e) Bromine 21. Which of the following is an ionic compound? (a) CO (b) SO2 (c) HF (d) HCl (e) Na2O 5 of 10
22. 2.50 g of an unknown base is dissolved in 289 ml of water and has a concentration of 0.216 M. What is the identification of the unknown base? (a) LiOH (b) KOH (c) Ba(OH)2 (d) NaOH (e) Ca(OH)2 23. What is the total number of atoms contained in 2.00 moles of iron? (a) 1.20 x 10 24 (b) 12 x 10 24 (c) 1 x 10 24 (d) 6.02 x 10 23 (e) 1.2044 x 10 24 24. How many grams are in 2.05 x 10 23 molecules of dinitrogen pentoxide? (a) 317 g (b) 37 g (c) 0.00315 g (d) 37 kg (e) 36.8 g 25. Commercial grade fuming nitric acid contains about 90.0% HNO3 by mass with a density of 1.50 g/ml, calculate the molarity of the HNO3 solution. a) 21.4 M b) 0.214 M c) 2.14 M d) 21.4 mm e) 214 mm 26. An unknown hydrocarbon compound was analyzed for hydrogen by elemental analysis and results show that it contains 15.88 % H. What is the empirical formula? a) C8H18 b) C4H9 c) C2H4 d) CH e) C24H36 27. Which of the following compounds contains the largest number of atoms? a) 2.00 mol of NH3 b) 2.00 mol of H2SO4 c) 1.00 mol H2SO4 d) 1.00 mol HBr e) 2.00 mol HBr 6 of 10
28. Classify the following type of reaction: a) Combustion reaction b) Acid-Base reaction c) Redox reaction d) Displacement reaction e) None of the above C3H8(l) + 5O2(g) 3CO2(g) + 4H2O(g) 29. Hydrogen peroxide readily decomposes in the presence of a catalyst to form oxygen gas and water. What is the correct balanced reaction? a) 4HO2(aq) 3O2(g) + 2H2O(l) b) H2O2(aq) O(g) + H2O(l) c) 2H2O2(aq) O2(g) + 2H2O(l) d) 2H2O2(aq) 2O2(g) + 2H2O(l) e) 2H2O2(aq) O2(g) + H2O(l) 30. Hydrogen gas can react with chlorine gas to produce hydrogen chloride. Write a correct balanced reaction and identify the oxidizing agent. a) H2(g) + Cl2(g) 2HCl(g) and Cl2 is the oxidizing agent b) H H2(g) + Cl2(g) 2HCl(g) and Cl is the oxidizing agent c) H2(g) + Cl2(g) 2HCl(g) and H2 is the oxidizing agent d) H2(g) + Cl2(g) 2HCl(g) and H + is the oxidizing agent e) None of the above 31. How many grams are in 12.5 moles of Ba(OH)2? a) 2.14 kg b) 2.14 x 10 2 g c) 7.30 x 10 2 g d) 2.140 x 10 3 g e) 0.730 kg 32. Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula. a) HNO b) H2NO2 c) HN6O16 d) HN16O7 e) H2NO3 7 of 10
33. Balance the following equation: Ca3(PO4)2(s) + SiO2(s) + C(s) CaSiO3(s) + CO(g) + P4(s) a) Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) 3CaSiO3(s) + 8CO(g) + P4(s) b) Ca3(PO4)2(s) + 3SiO2(s) + 14C(s) 3CaSiO3(s) + 14CO(g) + P4(s) c) Ca3(PO4)2(s) + 3SiO2(s) + 8C(s) 3CaSiO3(s) + 8CO(g) + 2P4(s) d) 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) 6CaSiO3(s) + 10CO(g) + P4(s) e) 2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) 6CaSiO3(s) + 10CO(g) + 4P4(s) 34. Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water via the reaction below (NOTE: the reaction needs to be balanced). Calculate the mass of P4O10(s) formed when 225 g of PH3 reacts with excess O2(g). (a) 424. g (b) 940. g (c) 900. g (d) 56.3 g (e) 470. g PH3(g) + O2(g) P4O10(s) + H2O(g) 35. What is the percent yield for the following reaction if 119.3 g of PCl5 are formed when 61.3 g of Cl2 react with excess PCl3? (a) 43.7% (b) 85.0% (c) 51.4% (d) 66.3% (e) 195% PCl3(g) + Cl2(g) PCl5(g) 36. A standard solution of 0.243 M NaOH was used to determine the concentration of a hydrochloric acid solution. If 46.33 ml of NaOH is needed to neutralize 10.00 ml of the acid, what is the molar concentration of the acid? (a) 0.888 M (b) 0.0524 M (c) 1.12 M (d) 2.43 M (e) 2.26 M 8 of 10
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