Question

1.) Calculate  ΔHº_rxn ΔS_{surr and} ΔSºrxn to determine if the reaction is spontaneous at 298 K

ΔHº_{f :} PCl3(g) = -287 kj/mol

ΔSº_{f :}  PCl3(g) = -3112 J/mol *K

ΔSº_{f :} P4(s) = 41.1 J/mol*K

ΔSº_{f :} Cl2(g)= 2230 J/mol *K

P4(s) +6Cl2(g) ------> 4PCl3(g)

2.) Calculate ΔGº_{rxn from enthalpy and entropy values at 298 K}

_{4NH3 (g) +5O2(g) -----> 4 NO(g) +6H2O(g)}

ΔHº_{f : NO(g) = 90.29 kj/mol}

ΔHº_{f: H2O(g) = -241.826 kJ/mol}

ΔHº_{f: NH3(g) = -45.9 kJ/mol}

ΔSº_{f : NO(g) = 210.65 J/ mol *K}

ΔSº_{f : H2O(g) = 188.72 J/mol *K}

ΔSº_{f : NH3(g) = 193 J / mol * K}

ΔSº_{f : O2 (g) =205.0 J.mol * K}

_{3.) Calculate} ΔGº_{rxn from} ΔGºf values at 25ºC?

3H2 (g)+ Fe2O3(s) -------> 2Fe(s) + 3H2O(g)

ΔGº_{f : Fe2O3(s)= -743.6 kJ/mol}

ΔGº_{f : -2280.60 kJ/mol}

4.) For the following reaction at 298 K , ΔSº_{rxn= -308.2 J/K*mol and} ΔHº_{rxn = -192.7 kJ/mol}

_{4NO (g)-----> N2O(g) +N2O3(g)}

_Calculate ΔGº_{rxn :}

ΔGº_{rxn =} ΔHº_{rxn -} TΔSº_rxn

_{1.) Is the reaction spontaneous at 298 K ?}

_{2.) Would the reaction become more or less spontaneous at higher T ?}

_{3.) Assuming that} ΔS and ΔH don't change with T , find ΔG at 500 C. Is the reaction spontaneous at this temperature ?

4.) Assuming that ΔS and ΔH don't change with T , find T at which reaction changes spontaneity.