[填空题]
1.Describe the second law of thermodynamics in
the Clausius form:
the Kelvin form:
in terms of entropy:
2.Two identical containers are connected with a tube of negligible volume. Only one of the containers is filled with gas with a temperature of $275\,K$, which is the same as the surrounding temperature. A tap prevents the flow of the gas to the other container.
The tap is opened and the gas expands into the other container isothermally. This process absorbs $250\,J$ of heat from the surrounding. The surrounding temperature is $275\,K$ during the expansion.
1.Discuss the sign conventions used when the first law of thermodynamics is given by $Q=ΔU+W$.
2.Determine the work done by the gas during the expansion.ΔU= W= $J$
3.Calculate the change in entropy of the gas.ΔS= $J\,K^{-1}$
