Chapter 10, Problem 10.67PAE

Silicon forms a series of compounds analogous to the al-kanes and having the general formula Si_nH_2n+2. The first of these compounds is silane, SiH₄, which is used in the electronics industry to produce thin ultrapure silicon films. SiH₄(g) is somewhat difficult to work with because it is py-ropboric at room temperature—meaning that it bursts into flame spontaneously when exposed to air.

(a) Write an equation for the combustion of SiH₄(g). (The reaction is analogous to hydrocarbon combustion, and SiO₂ is a solid under standard conditions. Assume the water produced will be a gas.)

(b) Use the data from Appendix E to calculate ? for this reaction.

(c) Calculate $\Delta \text{G}°$ and show that the reaction is spontaneous at 25°C.

(d) Compare $\Delta \text{G}°$ for this reaction to the combustion of methane. (See the previous problem.) Are the reactions in these two exercises enthalpy or entropy driven? Explain.