SOLVED

81) List the following in order of increasing atomic radius: V, Sc, Fe, Ti A) Fe < V < Ti < Sc B) Sc < Ti < V < Fe C) Ti < V < Fe < Sc D) V < Fe < Sc < Ti E) Fe < Sc < Ti < V 82) List the following in order of increasing density: Ti, Pd, Nb, Pt A) Ti < Pt < Pd < Nb B) Nb < Ti < Pt < Pd C) Pd < Nb < Ti < Pt D) Pt < Pd < Nb < Ti E) Ti < Nb < Pd < Pt 83) The metallurgical method for obtaining a metal from its ore by roasting the ore and then reducing the resulting metal oxide is called ________. A) zone melting B) pyrometallurgy C) leaching D) hydrometallurgy E) flotation 84) Zinc oxide, a useful fungicide, can be prepared from zinc blende ore by roasting the ore in air and then purifying the resulting oxide. What mass of zinc oxide could be obtained from 5.00 kg of a zinc blende ore that analyzed at 48.6% zinc sulfide, if the net conversion is 66.7% efficient? A) 0.98 kg B) 1.35 kg C) 1.51 kg D) 1.89 kg E) 2.07 kg 85) What average current must be maintained to electroplate 6.5 g of chromium per hour from a solution of chromium(III) complex? A) 3.4 A B) 6.9 A C) 10 A D) 12 A E) 15 A 86) What mass of manganese dioxide, from pyrolusite ore, is required for production of 25 kg of potassium permanganate by a process which is 78% efficient? A) 18 kg B) 14 kg C) 25 kg D) 29 kg E) 32 kg 87) Write the equation for treatment of Ag with CN-. A) 4 Ag(s) + 2 CN- + O2(g) + 2 H2O(l) → 4 AgO(s) + 4 CO(g) + 4 NH- B) 4 Ag(s) + 8 CN- + O2(g) + 2 H2O(l) → 4 [AgCN]- + 4 CO(g) + 4 NH+ C) 4 Ag(s) + 8 CN- + O2(g) + 2 H2O(l) → Ag3N(s) + 4 OH- + AgC8(s) D) 4 Ag(s) + 8 CN- + O2(g) + 2 H2O(l) → 4 [Ag(CN)2]- + 4 OH- E) 4 Ag(s) + 8 CN- + O2(g) + 2 H2O(l) → 4 AgO(s) + 2 H2(g) + 2 CO + 6 CN- 88) What volume of 18 M sulfuric acid could be prepared from the sulfur dioxide formed by the smelting of 5.00 metric tons of copper(I) sulfide, assuming that only 50% of the sulfur dioxide can actually be converted to the acid? A) 790 L B) 870 L C) 940 L D) 1,200 L E) 1,600 L 89) Write the overall equation for reducing Cu2S to metallic copper. A) Cu2S(l) + C(s) → 2 Cu(l) + CS(g) B) Cu2S(l) + CO(g) → 2 Cu(l) + CO(g) + S(s) C) Cu2S(l) + 2 CO(g) + O2(g) → 2 Cu(l) + 2 CO2(g) + S(s) D) Cu2S(l) + O2(g) → 2 CuO(s) + S(s) E) Cu2S(l) + O2(g) → 2 Cu(l) + SO2(g) 90) A 0.535 g sample of pyrolusite ore (impure MnO2) is treated with 1.42 g oxalic acid (H2C2O4 ? 2H2O) in an acidic medium. Following this reaction, the excess oxalic acid is titrated with 0.1000 M KMnO4, 36.6 mL being required. What is the % MnO2 in the ore? The reactions are: H2C2O4 + MnO2 + 2 H+ → Mn2+ + 2 H2O + 2 CO2 5 H2C2O4 + 2 MnO4- + 6 H+ → 2 Mn2+ + 8 H2O + 10 CO2 A) 34.4% B) 61.1% C) 2.33% D) 1.22% E) 38.9%