Some Pure Metals Can Be Obtained from Their Ores Simply $\rightarrow$

question 49

Multiple Choice

Some pure metals can be obtained from their ores simply by heating to a high temperature to drive off the oxygen, but iron ore usually is refined by reacting it with carbon monoxide. Use the information in the following table to determine whether or not iron ore could be refined by heating to a high temperature and, if so, how high the temperature must be. The oxidation reaction producing iron ore is given below.
4Fe(s) + 3O₂(g) $\rightarrow$ 2Fe₂O₃(s)
Thermodynamic Properties $$\begin{array} { | c | c | c | c | } \hline \text { Parameter } & \mathbf { F e } & \mathbf { O } _ { 2 } & \mathrm { Fe } _ { 2 } \mathbf { O } _ { 3 } \\\hline & 0 & 0 & - 742 \\\Delta G _ { \mathrm { f } } ^ { \circ } & & & \\( \mathrm { kJ } / \mathrm { mol } ) & & & \\\hline &0 & 0& - 824 \\\Delta H _ { \mathrm { f } } ^ { \circ } & & & \\( \mathrm { kJ } / \mathrm { mol } ) & & & \\\hline & & & \\ S ^ { \circ } &27 &205 &87 \\ \mathrm { J } / ( \mathrm { mol } \cdot \mathrm { K } ) ] & & & \\\hline\end{array}$$

• A) Iron ore cannot be refined by heating because the oxidation reaction is spontaneous in the forward direction at all temperatures.
• B) Iron ore could be refined by heating, but temperatures in the range 500-1000 K are needed.
• C) Iron ore could be refined by heating, but temperatures in the range 2000-3000 K are needed.
• D) Iron ore could be refined by heating, but temperatures in the range 1000-2000 K are needed.
• E) Iron ore could be refined by heating, but the temperature must be greater than 3000 K.

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