One kg of air ($${R = 287\,\,J/kg}$$-$$K$$) under goes irreversible process between equilibrium state $$1\,\,\left( {{{20}^ \circ }C,\,\,0.9\,\,{m^3}} \right)$$ and equilibrium state $$2\,\,\left( {{{20}^ \circ }C,\,\,0.6\,\,{m^3}} \right).$$ The change in entropy $${s_2} - {s_1}$$ (in $$J/kg$$-$$K$$) is _________

A closed system contains $$10$$ $$kg$$ of saturated liquid ammonia at $${10^ \circ }C.$$ Heat addition required to convert the entire liquid into saturated vapour at a constant pressure is $$16.2$$ $$MJ.$$ If the entropy of the saturated liquid is $$0.88$$ $$KJ/kg.K,$$ the entropy (in $$kJ/kg.K$$) of saturated vapour is __________

Two identical metal blocks $$L$$ and $$M$$ (specific heat $$=0.4$$ $$kJ/kg.K$$), each having a mass of $$5$$ $$kg,$$ are initially at $$313$$ $$K.$$ A reversible refrigerator extracts heat from block $$L$$ and rejects heat to block $$M$$ until the temperature of block $$L$$ reaches $$293$$ $$K.$$ The final temperature (in $$K$$) of block $$M$$ is ___________.

An amount of $$100$$ $$kW$$ of heat is transferred through a wall in steady state. One side of the wall is maintained at $${127^ \circ }C$$ and the other side at $${27^ \circ }C$$. The entropy generated $$($$in $$W/K)$$ due to the heat transfer through the wall is _____________