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.3 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 ----------------------------------------------------------------------------------------- 3 13a 2 Mn atoms, 10 C atoms, 10 O atoms 3 13b 4 C atoms, 6 H atoms, 4 O atoms 3 13c 7 C atoms, 5 H atoms, 3 N atoms, 6 O atoms 3 17a Se2- 3 17b F- 3 17c Fe2+, Fe3+ 3 17d N3- 3 19a MnO4 - 3 19b NO2 - 3 19c H2PO4 - 3 19d NH4 + 3 19e PO4 3- 3 19f SO3 2- 3 25a 1 Mg2+, 2 CH3CO2 - 3 25b 1 Ti4+, 2 SO4 2- 3 25c 1 Al3+, 3 OH - 3 25d 1 K+, 1 H2PO4 - 3 25e 1 Cu2+, 1 CO3 2- 3 33a calcium acetate 3 33b nickel(II) phosphate 3 33c aluminum hydroxide 3 33d potassium dihydrogen phosphate 3 35a Ca(HCO3)2 3 35b KMnO4 3 35c Mg(ClO4)2 3 35d K2HPO4 3 35e Na2SO3 3 37 Mg3(PO4)3 magnesium phosphate 3 37 Mg(NO3)2 magnesium nitrate 3 37 Fe(NO3)3 iron(III) nitrate 3 37 FePO4 iron(III) phosphate 3 39 stronger forces in CaO: greater ion charges 3 41a dinitrogen pentaoxide 3 41b tetraphosphorus trisulfide 3 41c oxygen difluoride 3 41d xenon tetrafluoride 3 43a BrF3 3 43b XeF2 3 43c N2H4 3 43d P2F4 3 43e C4H10 3 45a 446.14 g/mol 5 Fe(C6H11O7)2 3 45b 90.19 g/mol 4 CH3CH2CH2CH2SH 3 45c 324.42 g/mol 5 C20H24N2O2 3 47a 126.07 g/mol 5 H2C2O4.2H2O 3 47b 246.48 g/mol 5 MgSO4.7H2O 3 49a 1.03x10^-3 mol 3 C14H10O4 3 49b 8.33x10^-4 mol 3 Pt(NH3)2Cl2 3 53a 1.80x10^-3 mol 3 C9H8O4 3 53a 0.02266 mol 4 NaHCO3 3 53a 5.205x10^-3 mol 4 C6H8O7 3 53b 1.08x10^21 molecules 3 C9H8O4 3 55a 57.82% C, 6.066% H, 16.86% N, 19.26% O 3 55b 76.86% C, 12.90% H, 10.24% O 3 55c 24.77% Co, 29.80% Cl, 5.084% H, 40.35% O 3 59 2.4x10^3 g 2 FeTiO3 3 63a 150.1 g/mol 4 empirical C2H3O3, molecular C4H6O6 3 63b 44.1 g/mol 3 empirical C3H8, molecular C3H8 3 63c 122.2 g/mol 4 empirical B5H7, molecular B10H14 3 69 molecular formula C10H14N2 3 71 12 waters/formula unit KAl(SO4)2.12H2O 3 77a 305.42 g/mol 5 3 77b 1.8x10^-4 mol 2 capsaicin 3 77c 70.78% C, 8.911% H, 4.587% N, 15.72% O 3 77d 39 mg 2 carbon in 5mg capsaicin 3 81a 62.07 g/mol 4 38.70% C, 51.55% O 3 81b 90.08 g/mol 4 40.00% C, 53.29% O dihydroxyacetone has larger %C & %O 3 83 36.76% Fe 4 tablet containing FeSO4 --> delivers more iron than other tablet 3 83 12.52% Fe 4 tablet containing Fe(C6H11O7)2 3 89a chlorine trifluoride 3 89b nitrogen trichloride 3 89c strontium sulfate, ionic 3 89d calcium nitrate, ionic 3 89e xenon tetrafluoride 3 89f phosphorus trichloride 3 89g potassium iodide, ionic 3 89h aluminum sulfide, ionic 3 89i oxygen difluoride 3 89j potassium phosphate, ionic 3 91 NH4 +, Br-, ammonium bromide, NH4Br 3 91 Ba2+, S2-, barium sulfide, BaS 3 91 Fe2+, Cl-, iron(II) chloride, FeCl2 3 91 Pb2+, F-, lead(II) fluoride, PbF2 3 91 Al3+, CO3 2-, aluminum carbonate, Al2(CO3)3 3 91 Fe3+, O2-, iron(III) oxide, Fe2O3 3 91 Al3+, PO4 3-, aluminum phosphate, AlPO4 3 91 Li+, Br-, lithium bromide, LiBr 3 91 Ba2+, NO3 -, barium nitrate, Ba(NO3)2 3 91 Al3+, O2-, aluminum oxide, Al2O3 3 91 Fe3+, CO3 2-, iron(III) carbonate, Fe2(CO3)3 3 95 molecular formula C4H12As2 3 97 Ni(CO)4 3 101 148 g 3 of Sb2S3 3 105 47.9 g/mol 3 M = Ti, titanium 3 109 ans (d) C9H12O5; error = wrong #mol in 100g; or wrong mole ratio calcd. 3 113 2.37x10^-4 mol 3 empirical formula = U3O8; mixture of uranium(IV) oxide & uranium(VI) oxide 3 113b 238.029 amu implies that U-238 is most abundant 3 113c UO2(NO3)2.6H2O in hydrated form