Thermodynamics Final

Front 1

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

Back 1

True

Front 2

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

Back 2

False

Front 3

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

Back 3

True

Front 4

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

Back 4

False

Front 5

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

Back 5

True

Front 6

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

Back 6

True

Front 7

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

Back 7

False

Front 8

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

Back 8

True

Front 9

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

Back 9

True (temperature and specific heat constant)

Front 10

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

Back 10

False

Front 11

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

Back 11

False

Front 12

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

Back 12

True

Front 13

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

Back 13

False

Front 14

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

Back 14

True

Front 15

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

Back 15

True

Front 16

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

Back 16

??

Front 17

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

Back 17

False

Front 18

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

Back 18

??

Front 19

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

Back 19

False

Front 20

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

Back 20

True

Front 21

Like entropy, exergy is produced by action of irreversibilities

Back 21

False

Front 22

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

Back 22

True

Front 23

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

Back 23

True

Front 24

The specific flow exergy cannot be negative

Back 24

False

Front 25

In a throttling process, energy and exergy are conserved

Back 25

False

Front 26

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

Back 26

True

Front 27

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

Back 27

True

Front 28

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

Back 28

True

Front 29

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

Back 29

True

Front 30

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

Back 30

False

Front 31

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

Back 31

True

Front 32

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

Back 32

False

Front 33

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

Back 33

True

Front 34

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

Back 34

False

Front 35

Exergy destruction is proportional to entropy production

Back 35

True

Front 36

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

Back 36

True