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Chapter 4 Chemical Reactions 3) (aq) indicates that the compound is dissolved in alcohol. Answer: True False Diff: 1 Reference: Section 4-1 5) In a solution of alcohol and water that is 70 % water, alcohol is the solvent. Answer: True False Diff: 1 Reference: Section 4-3 7) Calculations of the amounts of reactants used or products formed are called stoichiometry. Answer: True False Diff: 1 Reference: Section 4-3 8) The numbers in front of formulas in balanced equations are called stoichiometric coefficients. Answer: True False Diff: 1 Reference: Section 4-3 11) How many grams of N2 are required to react with 2.30 moles of Mg in the following process? 3 Mg + N2 → Mg3N2? (Mg = 24.3, N = 14.0 g/mol) A) (2.30/3)(28.0) B) (2.30/3) C) (2.30)(28.0) D) (2.30/3)/28.0 E) (2.30)(3)(28.0) Answer: A Diff: 1 Reference: Section 4-2 13) For the reaction 2 A1+ Fe2O3 → Al2O3 + 2 Fe, 2.5 g of A1 (27.0 g/mol) and 7.2 g of Fe2O3 (159.8 g/mol) produce how many g of Fe (55.9 g/mol)? A) 2.5 (55.9/27.0) B) 2.5 (55.9)(2)/(27.0)(2) C) 7.2 (55.9)(2)/158.9 D) 7.2 (55.9/158.9) E) 2.5 (55.9/158.9) Answer: C Diff: 1 Reference: Section 4-2 16) Gases emitted during volcanic activity often contain high concentrations of hydrogen sulfide and sulfur dioxide. These gases may react to produce deposits of sulfur according to the equation: 2 H2S(g) + SO2(g) → 3 S(s) + 2 H2O (g) For the complete reaction of 6.41 mol of hydrogen sulfide: A) 308 g of sulfur is formed B) 410 g of sulfur dioxide is consumed C) 231 g of water vapor is produced D) 320 g of total products result E) 628 g of total reactants are consumed Answer: A Diff: 3 Reference: Section 4-2 18) Choose the INCORRECT statement. A) A chemical equation is a shorthand way of representing a chemical reaction. B) Calculations of the amounts of reactants used or products formed are called stoichiometry. C) The numbers in front of formulas in balanced equations are called stoichiometric coefficients. D) Molarity is defined as moles of solute per kg of solution. E) The solvent determines the state of the solution. Answer: D Diff: 1 Reference: Section 4-3 22) 52.5 mL of a solution were diluted to a volume of 6.25 L and then had a concentration of 3.16 M. What was the molarity of the concentrated solution? A) 3.16(52.5/6.25) B) 3.16(6.25/52.5) C) (3.16)(52.5)(6.25) D) 3.16(52.5/6250) E) (6.25)(3.16)/0.0525 Answer: E Diff: 1 Reference: Section 4-3