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(a) What is meant by molar heat of combustion?
(b) State the Hess’s Law.
(c) Use the following standard enthalpies of combustion of graphite, hydrogen and enthalpy of formation of propane.

(i) Write the equation for the formation of propane.
(ii) Draw an energy cycle diagram that links the heat of formation of propane with its heat of combustion and the heats of combustion of graphite and
hydrogen.
(iii) Calculate the standard
heat of combustion of
propane.
(c) Other than the enthalpy of combustion, state one factor which should be considered when choosing a fuel.
(d) The molar enthalpies of neutralization for dilute hydrochloric acid and dilute nitric (V)acid are - 57.2k.j/mol while that of ethanoic acid is — 55.2kJ/mol. Explain this observation.