Polymerization of ethene to poly(ethylene) can be approximated by the simplified reaction
n C2H4(g) → (–C2H4–)n(s).
The process is characterized by ΔH<0 and ΔS<0; precise numerical values are omitted here for simplicity.
(a) Without performing numerical calculations, predict whether the polymerization is thermodynamically favorable at very low temperatures. Justify your prediction in terms of the signs of ΔH and ΔS.
(b) Predict how increasing the reaction temperature affects the spontaneity of the polymerization. Explain your reasoning using appropriate thermodynamic arguments.
(c) Industrial polymerizations are often carried out under conditions of elevated pressure as well as moderate temperature. Discuss qualitatively how high pressure can influence the Gibbs free energy change for this gas-to-solid transformation and thereby affect the extent of reaction.