23. The Second Law of Thermodynamics

(II) A real heat engine working between heat reservoirs at 970 K and 650 K produces 550 J of work per cycle for a heat input of 2500 J. Compare the efficiency of this real engine to that of an ideal (Carnot) engine.

A sophomore with nothing better to do adds heat to $0.350$ kg of ice at $0.0$°C until it is all melted. What is the change in entropy of the water?

Which of the following is an example of the second law of thermodynamics?

Which one of the following processes produces a decrease in the entropy of the system?

Which of the following statements is consistent with the Second Law of Thermodynamics?

Which of the following best describes the statement of the second law of thermodynamics?

(II) Calculate the change in entropy of 1.00 kg of water when it is heated from 0°C to 85°C. Make an estimate.

Which one of the following processes produces a decrease in the entropy of the system?

(II) If 0.45 kg of water at 100°C is changed by a reversible process to steam at 100°C, determine the change in entropy of the water.

Two samples of an ideal gas are initially at the same temperature and pressure. They are each compressed reversibly from a volume V to volume V/2, one isothermally, the other adiabatically. In which sample is the final pressure greater?

Why would you expect the total entropy change in a Carnot cycle to be zero? Do a calculation to show that it is zero.

Which of the following best explains how the diagram violates the $2^{\mathrm{nd}}$ law of thermodynamics?

Which of the following statements is a logical consequence of the second law of thermodynamics?

According to the second law of thermodynamics, what is the maximum possible efficiency of a heat engine operating between a hot reservoir at temperature $T_1$ and a cold reservoir at temperature $T_2$?

Which of the following statements about $S$ (entropy) is true?