Answer: The methane molecule, CH4, has the geometry shown

Chapter , Problem 118IE

(choose chapter or problem)

The methane molecule, \(\mathrm{CH}_{4}\), has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is "expanded," by simultaneously extending all four \(\mathrm{C}-\mathrm{H}\) bonds to infinity. We then have the process

\(\mathrm{CH}_{4}(\mathrm{~g}) \rightarrow \mathrm{C}(\mathrm{g})+4 \mathrm{H}(\mathrm{g})\)

(a) Compare this process with the reverse of the reaction that represents the standard enthalpy of formation of \(\mathrm{CH}_{4}(\mathrm{~g})\).

(b) Calculate the enthalpy change in each case. Which is the more endothermic process? What accounts for the difference in \(\Delta H^{\circ}\) values?

(c) Suppose that \(3.45 \mathrm{gCH}_{4}(\mathrm{~g})\) reacts with \(1.22 \mathrm{~g} F_{2}(\mathrm{~g})\), forming \(\mathrm{CH}_{4}(\mathrm{~g}) \text { and } \mathrm{HF}(\mathrm{g})\) as sole products. What is the limiting reagent in this reaction? If the reaction occurs at constant pressure, what amount of heat is evolved?

 

Equation Transcription:

   

   

     

Text Transcription:

CH4

C-H

CH4(g)C(g)+4H(g)

CH4(g)

\delta H°  

3.45 gCH4(g)    

1.22 g F2(g)    

CH4(g)  and  HF(g)