Chemistry 106: General Chemistry Syracuse University Exam #1, Fall 2003 Name Date The last page of this exam is a periodic table. (1) Platinum has a density of 21.4 g/cm3. What is the mass of 5.9 cm3 of this metal? (express correctly the number of significant figures in your answer) (a) (b) (c) (d) (e) (2) The number of significant figures in the mass measured as 0.05010 is (a) (b) (c) (d) (e) (3) 1 2 3 4 5 How many cubic centimeters equals one cubic meter? (a) (b) (c) (d) (e) (4) 0.276 g 1.3 x 102 g 126. g 3.6 g 3.63 g 109 106 103 10-6 10-9 The experiment performed in Rutherford's laboratory on the scattering of particles by gold foil: (a) (b) (c) (d) (e) CHE 106 confirmed the plum-pudding model of the atom. led to the discovery of the atomic nucleus. utilized the deflection of beta particles by the gold foil. determined he charge of an electron involved none of the above 1 Fall 2002 Exam Questions (5) Which of the following statements is/are incorrect? I. II. III. IV. (a) (b) (c) (d) (e) (6) protons electrons neutrons isotopes nucleons What is the mass in grams of 4.25 x 1022 molecules of water? (a) (b) (c) (d) (e) (8) III III and IV I, II, and III II, III, and IV I and II The following species, 34Se2-, 36Kr, and 38Sr2+, all have the same number of (a) (b) (c) (d) (e) (7) The formula for calcium phosphate is Ca2(PO4)3. The formula for iron(III) sulfide is FeS. The correct name for Mg(CO3)2 is manganese carbonate. The formula for gallium nitride is GaN. 0.0127 g 1.27 g 1.42 g 14.2 g 7.65 x 1023 g You are a space explorer who has traveled to a special planet in a far-off galaxy. This planet is identical to Earth in size and chemical composition. You find a chemistry textbook (always the first thing you should look for when away from home) and learn that on that planet the mass of as 12C6 atom is defined as 12 amu but the formal definition of a mole is the "quantity of any substance that contains as many atoms, molecules, or formula units as the number of atoms in exactly 6 grams of 12C6". What then would be the molar mass of methane (CH4) as shown in this textbook? (a) (b) (c) (d) (e) CHE 106 32.0 g 16.0 g 8.0 g 6.0 g cannot be determined from the information given. 2 Fall 2002 Exam Questions (9) Which of the following statements is/are correct? I. II. The molecular weight of sodium sulfide is 55.1 amu. In a mole of CuSO4.5H2O there are 9 times Avogadro's number of oxygen atoms. III. A compound whose empirical formula is CH2O and molecular weight is 180.0 amu has a molecular formula of C4H8O2. IV. Starting with 20 moles of H2, one can produce 30 moles of NH3 using the Haber Process: N2(g) + 3 H2(g) ------> 2 NH3. (a) (b) (c) (d) (e) (10) The formula of the carbonate ion, ammonium ion, and the chlorate ion are represented, respectively, as (a) (b) (c) (d) (e) (11) CO32-, NH21-, ClO31CO32-, NH3+, ClO21CO21-, NH4+, ClO1CO32-, NH4+, ClO31P3-, NH3+, ClO21- The formula for aluminum sulfate is (a) (b) (c) (d) (e) (12) I and II II and III III and IV II I and IV Al2(CO3)3 Al2(SO4)3 Al3(SO4)2 Al2S3 Al3S2 The complete combustion of octane, C8H18, yields carbon dioxide and water: C8H18 + O2 ------> CO2 + H2O The coefficient of oxygen in the balanced equation is (a) (b) (c) (d) (e) CHE 106 17 19 23 25 34 3 Fall 2002 Exam Questions (13) Which one of the following equations is properly balanced? (a) (b) (c) (d) (e) (14) How many atoms of carbon are there in 0.40 mole of procaine, C13H20N2O2, a "pain killer" used by dentists? (a) (b) (c) (d) (e) (15) 4.8 x 1023 9.6 x 1023 3.1 x 1023 6.3 x 1024 9.6 x 1024 What is the mass of oxygen in 0.375 mol of Co(CO)8? (a) (b) (c) (d) (e) (16) NH4NO3 ------> 2 H2O + N2 CH3CHO + 3 O2 ------> 2 CO2 + 2 H2O Sn + 4 HNO3 ------> SnO2 + 4 NO2 + 2 H2O 2 Na2SO4 + 3 Bi(NO3)3 ------> Bi2(SO4)3 + 9 NaNO3 Na2CO3 + 2 H2SO4 ------> Na2SO4 + 2 H2O + CO2 16.0 g 32.0 g 48.0 g 64.0 g 80.0 g Elemental sulfur can be converted into sulfur trioxide by reaction with oxygen in the presence of a catalyst. Upon addition of water, sulfuric acid is produced as represented by the equation: S8(s) + 12 O2(g) + 8 H2O(l) ------> 8 H2SO4(l) What is the minimum mass of sulfur that is needed to prepare 175 g of H2SO4? (a) (b) (c) (d) (e) CHE 106 39.6 g 57.2 g 71.8 g 75.3 g 81.9 g 4 Fall 2002 Exam Questions (17) Which of the following statements is/are incorrect? I. II. III. (a) (b) (c) (d) (e) (18) H+(aq) + OH-(aq) ------> H2O(l) is the net ionic equation for the neutralization of HNO3(aq) with KOH(aq). HIO is a strong acid. The net ionic equation for the reaction of Na2S with HBr is S2-(aq) + 2H+(aq) ------> H2S(g). I II III I and II II and III Which of the following statements is/are incorrect? I. The spectator ions when lead(II) acetate(aq) is added to potassium sulfate(aq) are C2H3O2-(aq) and K+(aq). II. The net ionic equation when (NH4)2SO4(aq) is added to LiBr(aq) is: Li+(aq) + SO42-(aq) ------> Li2SO4(s) III. The molecular equation when NiCl2(aq) is added to Na3PO4(aq) is: NiCl2(aq) + Na3PO4 ------> NR (a) (b) (c) (d) (e) (19) I II I and II I and III II and III What is the volume (mL) of a 0.225 M NaOH solution needed to just neutralize 50.0 mL of a 0.0875 M H2SO4 solution, according to the reaction: 2 NaOH(aq) + H2SO4(aq) ------> 2H2O(l) + Na2SO4(aq) (a) (b) (c) (d) (e) CHE 106 19.0 mL 38.0 mL 57.1 mL 76.1 mL None of the above. 5 Fall 2002 Exam Questions (20) In a laboratory, 35.0 mL of 6.0 M sulfuric acid was spilled. Before the spill could be cleaned up, it had to first be neutralized with NaHCO3 according to the equation: H2SO4 + 2 NaHCO3 ------> 2 H2O + 2 CO2 + Na2SO4 The weight of NaHCO3 needed for neutralization of the spill was (a) (b) (c) (d) (e) (21) If 25.8 mL of a AgNO3 solution is needed to precipitate all of the chloride in 895 mg of KCl (forming AgCl), the molarity of the AgNO3 solution is (a) (b) (c) (d) (e) (22) 12.0 M 0.347 M 0.465 M 0.0847 M 0.012 M Aqueous solutions of sodium sulfide and copper(II) chloride are mixed together. Which statement if correct? (a) (b) (c) (d) (e) (23) 0.42 g 8.8 g 18 g 21 g 35 g Both NaCl and CuS precipitate from the solution. No precipitate forms. CuS will precipitate from solution. NaCl will precipitate from solution. No reaction will occur. A 230 mL sample of a 0.275 M solution is left on a hotplate overnight. The following morning the solution is 1.1 M. What volume of solvent has evaporated from the 0.275 M solution? (a) (b) (c) (d) (e) CHE 106 58 mL 63.3 mL 172 mL 230 mL 288 mL 6 Fall 2002 Exam Questions