Chapter 21, Problem 21.135MP

At high temperatures, coke reduces silica impurities in iron ore to elemental silicon:

     ${\text{SiO}}_{\text{2}}\left(s\right)+2\text{C}\left(s\right)\to \text{Si}\left(s\right)+2\text{CO}\left(g\right)$

1. (a) Use the data in Appendix B to calculate the values of ΔH°, ΔS°, and ΔG° for this reaction at 25 °C.
2. (b) Is the reaction endothermic or exothermic?
3. (c) Account for the sign of the entropy change.
4. (d) Is the reaction spontaneous at 25 °C and 1 atm pressure of CO?
5. (e) Assuming that ΔH° and ΔS° do not depend on temperature, estimate the temperature at which the reaction becomes spontaneous at 1 atm pressure of CO.