A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy $$\Delta $$U of the gas in joules will be

For a sample of perfect gas when its pressure is changed isothermally from p_i to p_f, the entropy change is given by

The heat of combination of carbon to CO₂ is $$-$$393.5 kJ/mol. The heat released upon formation of 35.2 g of CO₂ from carbon and oxygen gas is

For the reaction, $${X_2}{O_{4\left( l \right)}}\,\, \to \,\,2X{O_{2(g)}}$$

$$\Delta $$U = 2.1 kcal, $$\Delta $$S = 20 cal K^$$-$$1 at 300 K

Hence, G is