Exam 20: Entropy and the Second Law of Thermodynamics

Let k be the Boltzmann constant.If the thermodynamic state of gas at temperature T changes isothermally and reversibly to a state with three times the number of microstates as initially, the energy input to gas as heat is:

For one complete cycle of a reversible heat engine, which of the following quantities is NOT zero?

Is it possible to transfer energy from a low-temperature reservoir to a high-temperature reservoir?

The change in entropy is zero for:

Which of the following processes leads to a change in entropy of zero for the system undergoing the process?

Let k be the Boltzmann constant.If the configuration of molecules in a gas changes from one with a multiplicity of M₁ to one with a multiplicity of M₂, then entropy changes by:

A Carnot heat engine and an irreversible heat engine both operate between the same high temperature and low temperature reservoirs.They absorb the same heat from the high temperature reservoir as heat.The irreversible engine:

The maximum theoretical efficiency of a Carnot engine operating between reservoirs at the steam point and at room temperature is about:

The temperature T_L of the cold reservoirs and the temperatures T_H of the hot reservoirs for four Carnot heat engines are Rank these engines according to their efficiencies, least to greatest

A slow (quasi-static)process is NOT reversible if:

For all reversible processes involving a system and its environment:

An ideal gas expands into a vacuum in a rigid vessel.As a result there is:

Twenty-five identical molecules are in a box.Microstates are designated by identifying the molecules in the left and right halves of the box.The Boltzmann constant is 1.38 * 10^-23 J/K.The entropy associated with the configuration for which 15 molecules are in the left half and 10 molecules are in the right half is:

A perfectly reversible heat pump with a coefficient of performance of 14 supplies energy to a building as heat to maintain its temperature at 27 $\degree$ C.If the pump motor does work at the rate of 1 kW, at what rate does the pump supply energy to the building?

A heat engine absorbs energy of magnitude $\vert$ Q_H $\vert$ from a high temperature reservoir, does work of magnitude $\vert$ W $\vert$ , and transfers energy of magnitude $\vert$ Q_L $\vert$ as heat to a low temperature reservoir.Its efficiency is:

A certain heat engine draws 500 cal/s from a water bath at 27 $\degree$ C and transfers 400 cal/s to a reservoir at a lower temperature.The efficiency of this engine is:

The thermodynamic state of gas changes configuration from one with 3.8 *10¹⁸ microstates to one with 7.9 * 10¹⁹ microstates.The Boltzmann constant is 1.38 * 10^-23 J/K.The change in entropy is:

Twenty-five identical molecules are in a box.Microstates are designated by identifying the molecules in the left and right halves of the box.The multiplicity of the configuration with 15 molecules in the right half and 10 molecules in the left half is:

For a system of molecules,

For all adiabatic processes: