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36 Cards in this Set

  • Front
  • Back

For closed systems undergoing processes involving internal irreversibilities, both entropy change and entropy production are positive in value

True

The Carnot cycle is represented on a Mollier diagram by a rectangle

False

Entropy change of a closed system during a process can be greater than, equal to, or less than zero

True

For specified inlet state, exit pressure and mass flow rate, the power input required by a compressor operating at steady state is less than that if compression occurred isentropically

False

The TdS equations are fundamentally important in thermodynamics because of their use in deriving important property relations for pure, simple compressible systems

True

At liquid states, the following approximation is reasonable for many engineering applications: s(T, p) = sf(T)

True

The steady state form of the control volume entropy balance requires that the total rate at which entropy is transferred out of the control volume be less than the total rate at which entropy enters

False

In statistical thermodynamics, entropy is associated with the notion of microscopic disorder

True

For a gas modeled as an ideal gas, the specific internal energy, enthalpy and entropy all depend on temperature only

True (temperature and specific heat constant)

The entropy change between two states of water can be read directly from the steam tables

False

The increase of entropy principle states that the only processes of an isolated system are those for which its entropy increases

False

Bernoulli's equation applies generally to one-inlet, one-exit control volumes at steady state, whether internal irreversibilities are present or not

True

The only entropy transfer to, or from, control volumes is that accompanying heat transfer

False

Heat transfer for internally reversible processes of closed systems can be represented on a temperature-entropy diagram as an area

True

For a specified inlet state, exit pressure, and mass flow rate, the power developed by a turbine operating at steady state is less than if expansion occurred isentropically

True

The entropy change between two steady states of air modeled as an ideal gas can be directly read from Table A-22 only when pressure at these states is the same

??

The term isothermal means constant temperature, whereas isentropic means constant specific volume

False

When a system undergoes a Carnot cycle, entropy is produced within the system

??

The well-to-wheel efficiency compares different options for generating electricity used in industry, business and the home

False

Exergy accounting allows the location, type, and true magnitudes of inefficiency and loss to be identified and quantified

True

Like entropy, exergy is produced by action of irreversibilities

False

At every state, exergy cannot be negative; yet exergy change between two states can be positive, negative or zero

True

To define exergy, we think of two systems: a system of interest and an exergy reference environment

True

The specific flow exergy cannot be negative

False

In a throttling process, energy and exergy are conserved

False

If unit costs are based on exergy, we expect the unit cost of the electricity generated by a turbine to be greater than the unit cost of the high pressure steam provided to the turbine

True

When a closed system is at the dead state, it is in thermal and mechanical equilibrium with the exergy reference environment, and the values of the system's energy and thermomechanical exergy are each zero

True

The thermomechanical exergy at a state of a system can be thought of as the magnitude of the minimum theoretical work required to bring the system from the dead state to the given state

True

The exergy transfer accompanying heat transfer occuring at 1000 K is greater than the exergy transfer accompanyng an equivalent heat transfer occuring at T0= 300 K

True

When products of combustion are at a temperature significantly greater than required by a specific task, we say the task is well matched to the fuel source

False

Exergy is a measure of the departure of the state of a system from that of the exergy reference environment

True

The energy of an isolated system must remain constant, but its exergy can only increase

False

When a system is at T0 and p0, the value of its thermomechanical contribution to exergy is zero but its chemical contribution does not necessarily have a zero value

True

Mass, volume, energy, entropy and exergy are all intensive properties

False

Exergy destruction is proportional to entropy production

True

Exergy can be transferred to, and from, closed systems accompanying heat transfer, work and mass flow

True