Question 1

Which of these reactions represents the removal of silica from iron ore in a blast furnace

Accepted Answer

A)  SiO2(s)   →\rarr→  SiO2(g) 
B)  SiO2(s)  + CaO(s)   →\rarr→  CaSiO3(l) 
C)  SiO2(s)  + 4HF(g)   →\rarr→  SiF4(g)  + 2H2O(g) 
D)  SiO2(s)  + C(s)   →\rarr→  Si(l)  + CO2(g) 
E)  SiO2(s)  + CO(g)   →\rarr→  SiCO3(l)  F) C) and E)
G) A) and C)

Question 2

In p-type semiconductors,

Accepted Answer

A)   the semiconductors are "ultra purified" to increase conductivity.
B)   the valence and conduction bands are formed exclusively from "p orbitals."
C)   the semiconductors are "patented" for use in commercial applications.
D)   acceptor impurities are added to provide "positive holes" that increase the electrical conductivity of the semiconductor.E) A) and D)
F) A) and C)

Question 3

How much energy (kJ)  is released when 15.0g of Fe(l)  is produced in the thermite reaction
2Al(s)  + Fe2O3(s)   →\rarr→ Al2O3(s)  + 2Fe(l)   Δ\DeltaΔ H ∘\circ∘  = - 822.8 kJ/mol

Accepted Answer

A)   12,300 kJ
B)   221 kJ
C)   110. kJ
D)   6,170 kJ
E)   54.8 kJ F) B) and E)
G) B) and D)

Exam 21: Metallurgy and the Chemistry of Metals

Which of these reactions represents the removal of silica from iron ore in a blast furnace

Correct Answer
verified

In p-type semiconductors,

Correct Answer
verified

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H^$\circ$ = - 822.8 kJ/mol

Correct Answer
verified

Exam 21: Metallurgy and the Chemistry of Metals

Which of these reactions represents the removal of silica from iron ore in a blast furnace

Correct AnswerverifiedShow Answer

In p-type semiconductors,

Correct AnswerverifiedShow Answer

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction 2Al(s) + Fe2O3(s) →\rarr→ Al2O3(s) + 2Fe(l) Δ\DeltaΔ H ∘\circ∘ = - 822.8 kJ/mol

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

How much energy (kJ) is released when 15.0g of Fe(l) is produced in the thermite reaction 2Al(s) + Fe₂O₃(s) $\rarr$ Al₂O₃(s) + 2Fe(l) $\Delta$ H^$\circ$ = - 822.8 kJ/mol

Correct Answer
verified