Study your flashcards anywhere!
Download the official Cram app for free >
 Shuffle
Toggle OnToggle Off
 Alphabetize
Toggle OnToggle Off
 Front First
Toggle OnToggle Off
 Both Sides
Toggle OnToggle Off
 Read
Toggle OnToggle Off
How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
Up/Down arrow keys: Flip the card between the front and back.down keyup key
H key: Show hint (3rd side).h key
A key: Read text to speech.a key
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 oneinlet, oneexit 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 temperatureentropy 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 A22 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 welltowheel 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 