Updated Oct.15/04 ----------------------------------------------------------------------------------------- NUMERICAL ANSWERS TO ASSIGNED TUTORIAL PROBLEM SETS FOR CHEM205 FROM KOTZ & TREICHEL'S CHEMISTRY & CHEMICAL REACTIVITY ----------------------------------------------------------------------------------------- NOTE: none of the answers from Ch.4 have been verified NOTE: "^" means "raised to the power of..." to indicate scientific notation... NOTE: I cannot represent superscripts/subscripts here -- so...for polyatomic ions, I have left a space between the ion's formula and its charge Ch. Q# Answer Units SFs Comments ----------------------------------------------------------------------------------------- 4 1 formulas, states & relative amounts of reactants & products 4 11a SF4(g) + 2H2O(l) --> SO2(g) + 4HF(l) 4 11a sulfur tetrafluoride, water, sulfur dioxide, hydrogen fluoride 4 11b 4NH3(aq) + 5O2(g) --> 4NO(g) + 6H2O(l) 4 11b ammonia, oxygen, nitrogen monoxide, water 4 11c BF3(g) + 3H2O(l) --> 3HF(aq) + 3H3BO3(l) 4 11c boron trifluoride, water, hydrogen fluoride, hydrogen borate (boric acid) 4 15a 318 g 3 Fe 4 15b 239 g 3 CO 4 17a CO2 carbon dioxide, H2O water 4 17b CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l) 4 17c 102 g 3 oxygen O2 4 17d 128 g 3 products 4 19a BaCl2(aq) + 2AgNO3(aq) --> 2AgCl(s) + Ba(NO3)2(aq) 4 19b 0.255 g 3 AgNO3 4 19b 0.215 g 3 AgCl 4 21 0.125mol S8; 1.00mol Cl2; 1mol S8 : 4mol Cl2 --> S8 is limiting reagent 4 23a 0.100mol Al; 0.0573mol Cl2; 2mol Al : 3mol Cl2 -- Cl2 is limiting 4 23b 5.09 g 3 AlCl3 4 23c 1.03 g 3 Al used; 1.67 g Al remains 4 25 1.30x10^2 g 3 maximum mass aspirin produced 4 29a 9.37 g 3 CH3COSCH3 4 29b 92.3 % 3 percent yield 4 31 91.4 % 3 percent CuCl2.2H2O in original mixture 4 35 8.79 % 3 0.0672g Al in 0.764g sample 4 39a empirical formula C5H4 4 39b molecular formula C10H8 4 43 empirical formula Fe(CO)5 4 45a Ca3(PO4)2(s) + 2H2SO4(aq) --> Ca(H2PO4)2(aq) + 2 CaSO4(s) 4 45b 2NaBH4(s) + H2SO4(aq) --> B2H6(g) + 2H2(g) + Na2SO4(aq) 4 45c WO3(s) + 3H2(g) --> W(s) + 3H2O(l) 4 45d (NH4)2Cr2O7(s) --> N2(g) + 4H2O(l) + Cr2O3(s) 4 47 36.6 g 3 mass of product = mass of reactants 4 49 0.28 g 2 arginine 4 49 0.21 g 2 ornithine 4 51a titanium(IV) chloride, water, titanium(IV) oxide, hydrogen chloride 4 51b 4.60 g 3 H2O 4 51c 10.2 g 3 TiO2 4 51c 18.6 g 3 HCl 4 53 75.92 % 4 saccharin 4 57 empirical formula C3H2O note: problem should have read: "A 0.7184 g sample of impure NaHCO3…" 4 65 92.76 % 4 NaHCO3