Question

Calculate the enthalpy change on the formation of methane gas from the elements, using the following data at 25 degrees celsius and one bar pressure:
Heat of Combustion = 393.51 kj/mol
Heat of formation of Water Vapor = 241.82 kj/mol
Heat of combustion of methane gas to liquid water = 890.36 kj/mol
Heat of vaporization of water = 583.91 kj/mol

Answer 1

∆H = m x s x ∆T

(393.51+890.36)-(583.91+241.82)

= 1283.87-825.73

= 458.14

458.14×298

= 136525.72kJ/mol