SOLVED

41) Choose the INCORRECT statement about metallurgy. A) Zone refining is refining to a certain zone of purity. B) Refining is the removal of impurities from a metal. C) The Kroll process uses Mg to reduce TiCl4 to titanium. D) Zone refining uses a heating coil which passes along the rod of material. E) In zone refining impurities remain in the molten area. 42) Choose the INCORRECT statement. A) The extraction of copper is complicated by iron. B) Blister copper has bubbles of air on the surface of the copper. C) Refining to high purity copper is done electrolytically. D) Pyrometallurgy is the roasting of an ore followed by reduction of the ore to metal. E) “Pyro” as a prefix indicates high temperatures. 43) Choose the INCORRECT statement. A) Hydrometallurgy handles materials as aqueous solutions. B) The three steps of hydrometallurgy are leaching, purification and/or concentration and precipitation. C) Leaching is adding chemicals to eat away the ore, leaving the metal. D) Purification in hydrometallurgy is to remove impurities and concentrate solutions. E) Purification in hydrometallurgy may include evaporation of water, ion exchange, and/or use of activated charcoal. 44) Find the FALSE combination of a metallurgical process and its example: A) leaching: 4 Au(s) + 8 CN-(aq) + O2(g) + 2 H2O(l) → 4 [Au(CN)2]-(aq) + 4 OH-(aq) B) reduction: ZnCO3(s) → ZnO(s) + CO2(g) C) roasting: 2 Cu2S(s) + 3 O2(g) → 2 Cu2O(s) + 2 SO2(g) D) precipitation: Zn2+(aq) + S2-(aq) → ZnS(s) E) conversion: 2 Co(OH)3(s) Co2O3(s) + 3 H2O(g) 45) What volume of carbon monoxide, measured at 1200°C and 720 torr, would be released when 5.0 kg of an ore containing 45% zinc oxide as the only reacting species is treated with excess carbon? [ZnO + C → Zn + CO] A) 1.2 × 102 L B) 1.5 × 103 L C) 3.5 × 103 L D) 7.8 × 103 L E) 7.0 × 1 04 L 46) What are the formulas of the missing compounds, 1 and 2, respectively, in the reaction below? This reaction is used in the production of metallic zinc. ZnO(s) + 1 → Zn(g) + 2 A) C(s) and CO(g) B) CO(g) and ZnCO3(s) C) CO(g) and C(s) D) C(s) and CO2(g) 47) At 273 K, ΔG° for the reaction 2 C + O2 → 2 CO is about -280 kJ, and at 1480 K is about -580 kJ. For the reaction 2 Zn + O2 → 2 ZnO ΔG° at 273 and 1480 K, respectively, is -640 and -280 kJ. Calculate ΔG° at 273 and 1480 K, respectively, for the reduction of zinc oxide by carbon. A) +180 and -150 kJ B) +360 and -300 kJ C) -360 and +300 kJ D) -180 and +150 kJ 48) Choose the INCORRECT statement. A) Iron is the most widely used metal from the earth’s crust. B) The simplified equation for the reduction of iron is Fe2O3(s) + 3 CO(g) → 2 Fe(l) + 3 CO2(g). C) One process in the making of steel from pig iron is to reduce the carbon content. D) The product of a blast furnace is steel. E) The solid reactants in a blast furnace are iron ore, coke, and a slag-forming flux. 49) Choose the INCORRECT statement. A) The product of a blast furnace is pig iron. B) Cast iron is pig iron poured directly into molds. C) Pig iron is converted to steel by reducing the carbon content, removing Si, Mn, P, and other impurities, and adding alloying elements. D) The most important method of steel-making today is the basic oxygen process. E) In the basic oxygen process, oxygen is bubbled into the blast furnace. 50) Choose the INCORRECT statement. A) In steel making, DRI stands for Detection and Recovery of Iron. B) In the basic oxygen process, a lance is a water cooled tube to deliver limestone and oxygen. C) Alloying elements with steel include Cr, Ni, Mn, V, Mo and W. D) The direct reduction of iron depends on the availability of natural gas. E) Steel is an alloy of iron.