91) The simplified equation for the reduction of iron ore is: Fe2O3(s) + CO(g) → Fe(l) + CO2(g) When it is balanced, the coefficients are ________. A) 1, 3, 2, 3 B) 1, 3, 1, 3 C) 1, 1, 1, 2 D) 2, 6, 3, 3 E) 1, 1, 2, 1 92) How much carbon monoxide is required to reduce 2.00 metric tons (2000 kg) of iron ore if the ore is 5.03% iron? Fe2O3(s) + 3 CO(g) → 2 Fe(l) + 3 CO2(g) A) 151 kg B) 75.7 kg C) 25.2 kg D) 40.7 kg E) 50.5 kg 93) Write the chemical equation for the reduction of Cr2O3 to chromium with silicon as the reducing agent. A) Si(s) + Cr2O3(s) → SiO3(s) + Cr(l) B) Si(s) + Cr2O3(s) → SiO2(s) + 2 CrO(s) C) 3 Si(s) + 2 Cr2O3(s) → 3 SiO2(s) + 4 Cr(l) D) 3 Si(s) + Cr2O3(s) → 3 SiO(s) + 2 Cr(l) E) 4 Si(s) + Cr2O3(s) → SiO3(s) + 2 CrO(s) 94) Use the couples Cr2+ | Cr3+, -0.424 V and Cr3+ | Cr2O72-, -1.33 V to determine E° of Cr2O72- | Cr2+. A) -0.02 V B) 1.75 V C) -1.75 V D) 0.81 V E) -1.10 V 95) When permanganate ion serves as an oxidizing agent in acidic aqueous solution the manganese-containing product most likely to be formed is ________. A) Mn2+ B) MnO2 C) MnO4- D) MnO E) Mn 96) A 25.0 mL aliquot of a solution containing Fe2+, prepared during an assay of a pyrite ore, was titrated to a faint purple endpoint by 32.2 mL of 0.020 M KMnO4. What was the molarity of the Fe2+ solution? [The permanganate was reduced to Mn2+.] A) 0.13 M B) 0.19 M C) 0.26 M D) 0.31 M E) 0.47 M 97) Write the electron configuration for Fe2+. A) [Ar]3d6 B) [Ar]4s23d4 C) [Ar]4s24p4 D) [Ar]4s14p1 E) [Ar]5s2 98) Write the electron configuration for Co3+. A) [Ar]3d6 B) [Ar]4s23d4 C) [Ar]4s24p4 D) [Ar]4s14p1 E) [Ar]5s2 99) Which is most probably the ground state electron configuration for the iron(III) ion? A) [Ar]4s23d3 B) [Ar]4s13d4 C) [Ar]4s03d33p3 D) [Ar]4s04p5 E) [Ar]4s03d5 100) What is the approximate pH of the H+/H2 electrode compartment through which H2 gas is bubbled at a pressure of 1.00 atm if this electrode, when coupled with a Ni/(0.10 M) Ni2+ electrode, forms a galvanic cell having an initial potential of 0.10 V? [The discharge reaction involves oxidation of nickel to Ni2+.] A) 2.15 B) 4.65 C) 6.15 D) 3.15 E) 3.65 101) Gold does not react with either nitric acid nor hydrochloric acid alone, but can be dissolved by aqua regia to form the tetrachloroaurate(III) ion, water and nitric oxide. What is the sum of the coefficients when the net equation for this process is balanced? A) 17 B) 14 C) 11 D) 9 E) 7 102) The net formation constant for tetraamminezinc(II) is 4.1 × 108. What would be the approximate potential of the galvanic cell symbolized below? Zn/Zn(NH3)42+ (1.0 M), NH3(1.0 M)//Zn2+(1.0 M)/Zn A) 0.76 V B) 0.00 V C) 0.51 V D) 0.25 V