Modern Materials08

Modern Materials08 - Chem 112 Supplemental Problems Modern...

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Chem 112 Supplemental Problems Modern Materials METALLURGY 1. Which one of the following elements is most likely to be found as the free metal in nature? A. Ca B. Au C. Al D. Fe E. Zn 2. Which of the following oxides would be most useful as an additive to remove SiO 2 by an acid-base reaction in pyrometallurgy? A. V 2 O 5 B. Mn 2 O 7 C. CrO 3 D. Fe 2 O 3 E. CaO 3. Which one of the following elements uses hydrometallurgy as an important part in its processing? A. Pb B. Cr C. Fe D. Si E. Al 4. The following chemical reactions occur in a blast furnace during the refining of iron ore: 2C( s ) + O 2 ( g ) 2CO( g ) + heat heat + C( s ) + H 2 O( g ) CO( g ) + H 2 ( g ) Fe 3 O 4 ( s ) + 4CO( g ) 3Fe( l ) + 4CO 2 ( g ) Fe 3 O 4 ( s ) + 4H 2 ( g ) 3Fe( l ) + 4H 2 O( g ) The purpose of coke (C(s)) in a blast furnace is A. to reduce iron oxide to iron. B. to combine with oxygen and provide heat. C. to produce carbon monoxide, which reduces iron oxide to iron. D. all of the above. E. none of the above.
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5. The hydrometallurgical process used in refining gold ore entails converting metallic gold to a water-soluble complex. The formula of the complex is __________. A. Au(NH 3 ) 2 + B. Au(NH 3 ) 4 C. Au(CN) 2 D. Au(CO) 4 2 E. Au(CO) 4 + 6 Processes used to reduce metal ores or to refine metals that are based on the process of electrolysis are collectively referred to as __________. A. pyrometallurgy B. hydrometallurgy C. electrometallurgy D. calcination E. roasting 7. One of the ores containing copper is known as chalcocite. What is the oxidation state of copper in Cu 2 S? A. 0 B. +1 C. +2 D. +3 E. +4 8 The respective standard oxidation potentials for Cu Cu 2+ , Ni Ni 2+ , and Ag Ag + are (in V) -0.34, +0.28 and -0.80. Impure copper slabs at the anode are refined electrochemically, affording much purer metallic copper at the cathode. Which statement below is true? A. Cu is oxidized preferentially over both Ni and Ag, so both Ni and Ag metals are separated as sludges below the anode. B. Ni is oxidized preferentially over Cu, and Ni 2+ is reduced much less readily than Cu 2+ , so Ni is separated as Ni 2+ in the electrolyte solution. C. Ag is oxidized preferentially over Cu, and Ag + is reduced much less readily than Cu 2+ , so Ag is separated as Ag + in the electrolyte solution. D. Ag is oxidized preferentially over Cu, and Ag + is reduced much more readily than Cu 2+ , so Ag plates out with Cu at the cathode and cannot readily be removed from impure copper. E. Both Ni and Ag are oxidized preferentially over Cu and Ni 2+ , and Ag + is reduced much less readily than Cu 2+ , so Ni and Ag are separated as Ni 2+ and Ag + in the electrolyte solution.
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TRANSITION METALS 1. Which one of the following complex ions will be paramagnetic? A.
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Modern Materials08 - Chem 112 Supplemental Problems Modern...

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