In a blast furnace limestone (calcium carbonate) is decomposed into calcium oxide and carbon dioxide according to the equation:
CaCO_(3)(s)->CaO(s)+CO_(2)(g)
i. The standard enthalpies of formation of
CaCO_(3)(s),CaO(s)
and
CO_(2)(g)
are
-1207kJmol^(-1),-635kJmol^(-1)
and
-394kJmol^(-1)
respectively. Calculate the standard enthalpy change,
\Delta H⊖
, for the thermal decomposition of calcium carbonate. ii. The standard entropy values for
CaCO_(3)(s),CaO(s)
and
CO_(2)(g)
are
92.9JK^(-1)mol^(-1),40.0JKmol^(-1)
and
214JK^(-1)mol^(-1)
respectively. Calculate the change in entropy,
\Delta S⊖
, for the thermal decomposition of calcium carbonate. iii. Calculate the change in standard Gibbs energy,
\Delta G⊖
, for the thermal decomposition of calcium carbonate at
298K
. iv. State whether the thermal decomposition of calcium carbonate is spontaneous or non-spontaneous at
298K
. v. Explain why limestone cliffs are thermodynamically stable whereas limestone decomposes readily in a blast furnace.