$$2$$ moles of oxygen are mixed adiabatically with another $$2$$ moles of oxygen in mixing chamber, so that the final total pressure and temperature of the mixture become same as those of the individual constituents at, their initial states. The universal gas constant is given as $$R$$. The change in entropy due to mixing, per mole of oxygen, is given by

A cycle device operates between three thermal reservoirs, as shown in the figure. Heat is transferred to/from the cyclic device. It is assumed that heat transfer between each thermal reservoir and the cyclic device takes place across negligible temperature difference. Interactions between the cyclic device and the respective thermal reservoirs that are shown in the figure are all in the form of heat transfer.

The cyclic device can be

$$A$$ gas expands in a frictionless piston-cylinder arrangement. The expansion process is very slow, and is resisted by an ambient pressure of $$100kPa.$$ During the expansion process, the pressure of the system (gas) remains constant at $$300$$ $$kPa.$$ The change in volume of the gas is $$0.01{m^3}.$$

The maximum amount of work that could be utilized from the above process is

A thermal power plant operates on a regenerative cycle with a single open feed water heater, as shown in the figure. For the state points shown, the specific enthalpies are: $${h_1} = 2800\,\,kJ/kg$$ and $${h_2} = 200\,\,kJ/kg$$. The bleed to the feed-water heater is $$20\% $$ of the boiler steam generation rate. The specific enthalpy at state $$3$$ is