A system does 200 J of work and at the same time absorbs 150 J of heat. The magnitude of the change in internal energy is ____________ J. (Nearest integer)

At 298 K, the enthalpy of fusion of a solid (X) is 2.8 kJ mol^$$-$$1 and the enthalpy of vaporisation of the liquid (X) is 98.2 kJ mol^$$-$$1. The enthalpy of sublimation of the substance (X) in kJ mol^$$-$$1 is _____________. (in nearest integer)

If the standard molar enthalpy change for combustion of graphite powder is $$-$$2.48 $$\times$$ 10² kJ mol^$$-$$1, the amount of heat generated on combustion of 1 g of graphite powder is ___________ kJ. (Nearest integer)

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.