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34 Cards in this Set
- Front
- Back
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1) A perpetual motion machine of the second kind violates
a) The Zeroeth Law of Thermodynamics b) the First Law Thermodynamics c) the Second Law of Thermodynamics |
c
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2) A heat engine that has an efficiency of 100% violates the
a) The Zeroeth Law of Thermodynamics b) the First Law Thermodynamics c) the Second Law of Thermodynamics d) does not violate any thermodynamic laws |
c
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3) A piston cylinder device contains nitrogen gas. During a reversible adiabatic process, the entropy of the nitrogen will
a) never increase b) sometimes increase c) always increase |
a
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4) the entropy of the steam flowing through an actual adiabatic turbine will
a) increase b) stay the same c) decrease |
a
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5) around a cycle a system must reject as much heat as it receives T / F
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f
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6) an isothermal process is necessarily reversible T / F
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f
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7) A entropy of a hot potato decreases as it cools in contradiction to
increase of entropy principle T / F |
f
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8) A turbine operates between two given states as the design of the
turbine improves the reversible work between the two states remains the same T / F |
t
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What ones are reversible Processes
a) slow compression of a gas b) burning of a fuel c) mixing of oxygen and nitrogen gases d) the transfer between objects at the same temp e) the sudden expansion of a gas into a vacuum f ) the slow pressurization of a cylinder |
a,d,f,
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Carnot heat engines composed of reversible processes have efficiencies of 100% True or fales?
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F
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A process that violates the Second law of thermo also violates the first law. TF?
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F
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The "boundary work" dine by a control volume is always zero
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T
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A process that violates the First law of thermo must violates the second law. TF?
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F
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when a net amount energy is added by heat transfer to a closed system undergoing a reversible process a net amount of work is also done. TF?
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F
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A closed system can experience a decrease on entropy only by thermal energy leaving the system by heat transfer. TF?
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T
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if there is no change in entropy between two states of a closed system the process is necessarily adiabatic and internally reversable. TF?
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T
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The sum of all work around a thermodynamic cycle must equal zero. TF?
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F
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the value of a property around a thermodynamic cycle is always equal to zero. TF?
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T
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the first law of thermo is a statement of.....
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energy conservation
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each of the following is a reversible process except for...
a)the quasi-static adiabatic compression of air in a piston b)cooling of a heated cloths iron c)very slow discharg of a car battery |
b
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The conservation of mass principle states that...
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the net mass entering a control volume equals the mass stored in the control volume.
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The purpose of a throttling valve is too....
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reduce the pressure of the fluid.
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in the thermodynamic sense, flow work is the work
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done as a fluid moves into or out of a control volume
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which of the following does not change the entropy of a system.
a. heat transfer into the system b. friction c. heat transfer out of the system d. work |
d. work
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conrot cycle ∆s=
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0
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The Clausius statement is valid for what process?
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all
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A closed system experiences a reversible process where heat addition is the only energy transfer the entropy change will be positive, negative, 0, or equal to heat transfer.
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must be positive
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during an adiabatic, internally reversible process which is true aBOUT THE CHANGE IN ENTROPY?
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∆s=o
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two heat engines are operating between the same two thermal reservoirs. Both engines employ reversible processes but the first uses steam as a working fluid while the second uses air, which is more efficent?
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they r the same
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The efficiency of a carnot heat pump can be increased by
a. decreasing th b. increasing tc towords th c. decreasing Tc d. the efficiency of a carnot heat pump can not be increased, |
b
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kinetic energy of an ideal gas increases as it is accelerated in an adiabatic nozzle. The energy comes from
a. a decrease of the enthalpy of the gas b. the change in pressure of the gas c. heat transfer to the gas d. a decrease of the gas specific volume. |
a
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In isontropic process the area under the curve of the T- s diagram tells us what?
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heat transfer
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In isontropic process the area under the curve of the T- s diagram tells us what?
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heat transfer
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efficiency =
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Wnet / Qh
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