For a given chemical reaction A $$\to$$ B at 300 K the free energy change is $$-$$49.4 kJ mol^$$-$$1 and the enthalpy of reaction is 51.4 kJ mol^$$-$$1. The entropy change of the reaction is _____________ JK^$$-$$1 mol^$$-$$1.

For the reaction C₂H₆ $$ \to $$ C₂H₄ + H₂

the reaction enthalpy $$\Delta$$_rH = __________ kJ mol^$$-$$1. (Round off to the Nearest Integer).

[ Given : Bond enthalpies in kJ mol^$$-$$1 : C-C : 347, C = C : 611; C-H : 414, H-H : 436 ]

The standard enthalpies of formation of Al₂O₃ and CaO are $$-$$1675 kJ mol^-1 and $$-$$635 kJ mol^$$-$$1 respectively.

For the reaction

3CaO + 2Al $$ \to $$ 3Ca + Al₂O₃ the standard reaction enthalpy $$\Delta$$_rH⁰ = _________ kJ.

(Round off to the Nearest Integer)

At 25$$^\circ$$C, 50 g of iron reacts with HCl to form FeCl₂. The evolved hydrogen gas expands against a constant pressure of 1 bar. The work done by the gas during this expansion is _________ J. (Round off to the Nearest Integer).

[Given : R = 8.314 J mol^$$-$$1 K^$$-$$1. Assume, hydrogen is an ideal gas] [Atomic mass of Fe is 55.85 u]