Question

Please answer all questions, I will upvote thanks.

QUESTION 1 Which of the following statements about entropy is false? Entropy is a measure of molecular disorder. Entropy is a property and process path independent. Entropy is always generated during a process, including in a Carnot cycle. Entropy can decrease during a process. QUESTION 2 Which of the following statements about a reversible process is false? Reversible process is an idealized process that has no irreversibility involved. Work-consuming device consumes the least work when they operate on a reversible process No entropy is generated during a reversible process. Depending on the working fluid conditions, two reversible cyclic devices operated between the same two thermal reservoirs could have different thermal efficiencies. QUESTION 3 Which of the following statements about an isentropic compressor is correct? An isentropic compressor has internal irreversibilities. An isentropic compressor has internal irreversibilities. An isentropic compressor requires less work input than the actual adiabatic compressor. An isentropic compressor is an ideal model of a compressor with a cooling jacket. The temperature of an ideal gas flowing through an isentropic compressor remains constant during the compression process. QUESTION 4 A closed system experiences a process such that ASsys<0. From this information, we can conclude: The process was isothermal. The process was non-adiabatic. The process was irreversible The process was impossible.

Answer 1

QUESTION1

Which of the following statements about entropy is false?

ANSWER:

OPTION(III) Entropy is always generated during a process including, including in a Carnot cycle.

Explanation:

The above statement is false because according to the second law of thermodynamics the total entropy of the universe should either increase or remain constant. Since we know that the Carnot cycle has no entropy generation as it has two reversible adiabatic processes and two isothermal processes, so net entropy generation in the Carnot cycle is always zero.

QUESTION 2

Which of the following statements about a reversible process is false?

OPTION(IV): depending on the fluid condition, two reversible cycle devices operated between the same two thermal reservoirs could have different efficiencies.

Explanation:

The above statement is wrong because for the reversible cycle we know the efficiency as follows:

Efficiency for the reversible cycle = 1-(T_min / T_max)

So, we can see that as long as the temperature of the both reservoirs are the same efficiencies of both reversible devices must be the same.

QUESTION3: Which of the following statements about an isentropic compressor is correct?

ANSWER: (II) Isentropic compressor requires less work input than the actual adiabatic compressor.

Explanation: As per the isentropic efficiency of an isentropic compressor we know that the isentropic efficiency of a compressor is the ratio of the isentropic work to the actual adiabatic compression work. So, the isentropic compressor requires less work input than the actual adiabatic compressor.

QUESTION 4: A closed system experiences a process such that ΔSsys < 0, from the information we can conclude:

ANSWER (II) The process was non-adiabatic

Explanation:

As we know,

ΔSsys = dQ/T (for a process)

if ΔSsys < 0, it means that the system is losing heat, therefore, the system is non-adiabatic.