At low temperatures, mixtures of water and methane can form a hydrate (i.e. a solid containing trapped methane). Hydrates are potentially a very large source of underground trapped methane in the pole regions but are a nuisance when they form in pipelines and block the flow of natural gas. The approximate stoichiometry of hydrate formation is
CH4(g) + 5.75 H2O(s) ↔ CH4 5.75 H2O(s)
The equilibrium partial pressure of methane for hydrate formation is 2.0 MPa at 267 K and 1.5MPa at 255K.
i) Is the reaction endothermic or exothermic? Why?
ii) Use the information provided in the problem statement to calculate Δh.
iii) Use the information in the problem statement to calculate the equilibrium methane partial pressure for hydrate formation at 273 K.