ME121-Engineering Thermodynamics
System - answerrigid body bounded by certain boundaries
Surroundings - answereverything external to the system
Boundary - answerinterface between the system and the environment
Closed system - answeralways contains the same matter. Allows energy transfer but
there can be no transfer of mass across its boundary.
Open system - answerAllows both energy and mass transfer
Isolated system - answerIt is a type of system which is not in any way influenced by its
surroundings.
Property - answera macroscopic characteristic of a system such as
mass, volume, energy, pressure, and temperature to which a numerical value can be
assigned
at a given time without knowledge of the previous behavior (history) of the system.
State - answerrefers to the condition of a system as described by its properties. can
often be specified
by providing the values of a subset of the properties.
Process - answerWhen any of the properties of a system change, the state changes
and the system is said
to have undergone a _____________. It is a transformation from one state to another.
Steady state - answerIf a system exhibits the same values of its properties at two
different times, it is in the
same state at these times. A system is said to be at ________________ if none of its
properties
changes with time.
Transient - answerA response that unpredictable and changes over time.
Cycle - answerWhen a system in a given initial state goes through a number of different
changes of state or processes and finally returns to its initial state, the system has
undergone what kind of process?
, Extensive property - answerIts value for an overall system is the sum of its values for
the parts into which the system is divided. a property that changes when the size of the
sample changes and it can also change with time, e.g., mass, volume, energy
Intensive property - answervalues are independent of the size/extent of the system; may
vary from place to place within the system at any moment, (maybe functions of both
position and time) e.g., density, temperature, pressure, specific volume
Equilibrium - answerThis refers to when a system has reached a state where there is no
spontaneous change over time.
True - answerTrue or False. A quantity is a property if its change in values between two
states is independent of the process.
Kelvin-Planck Statement - answerIt is impossible for any device that operates on a cycle
to receive heat from a single reservoir and produce a net amount of work.
Phase - answerrefers to a quantity of matter that is homogeneous (all solid, liquid or
gas) throughout in both chemical
composition and physical structure.
False - answerTrue or false. A system cannot contain
one or more phases
Phase boundaries - answerIn the phase diagram, it is the line separating two different
phases.
Pure substance - answerone that is uniform and invariable in chemical composition. can
exist in more than one phase, but its chemical composition must be the same
in each phase.
Clausius Statement - answerIt is impossible for any system to operate in such a way
that the sole result would be an energy transfer by heat from a cooler to a hotter body.
True - answerTrue or False. A system consisting of air can be regarded as a pure
substance as
long as it is a mixture of gases; but if a liquid phase should form on cooling, the liquid
would
have a different composition from the gas phase, and the system would no longer be
considered
a pure substance.
Fourier's law - answerWhat is the governing law in the study of conductive heat
transfer?
System - answerrigid body bounded by certain boundaries
Surroundings - answereverything external to the system
Boundary - answerinterface between the system and the environment
Closed system - answeralways contains the same matter. Allows energy transfer but
there can be no transfer of mass across its boundary.
Open system - answerAllows both energy and mass transfer
Isolated system - answerIt is a type of system which is not in any way influenced by its
surroundings.
Property - answera macroscopic characteristic of a system such as
mass, volume, energy, pressure, and temperature to which a numerical value can be
assigned
at a given time without knowledge of the previous behavior (history) of the system.
State - answerrefers to the condition of a system as described by its properties. can
often be specified
by providing the values of a subset of the properties.
Process - answerWhen any of the properties of a system change, the state changes
and the system is said
to have undergone a _____________. It is a transformation from one state to another.
Steady state - answerIf a system exhibits the same values of its properties at two
different times, it is in the
same state at these times. A system is said to be at ________________ if none of its
properties
changes with time.
Transient - answerA response that unpredictable and changes over time.
Cycle - answerWhen a system in a given initial state goes through a number of different
changes of state or processes and finally returns to its initial state, the system has
undergone what kind of process?
, Extensive property - answerIts value for an overall system is the sum of its values for
the parts into which the system is divided. a property that changes when the size of the
sample changes and it can also change with time, e.g., mass, volume, energy
Intensive property - answervalues are independent of the size/extent of the system; may
vary from place to place within the system at any moment, (maybe functions of both
position and time) e.g., density, temperature, pressure, specific volume
Equilibrium - answerThis refers to when a system has reached a state where there is no
spontaneous change over time.
True - answerTrue or False. A quantity is a property if its change in values between two
states is independent of the process.
Kelvin-Planck Statement - answerIt is impossible for any device that operates on a cycle
to receive heat from a single reservoir and produce a net amount of work.
Phase - answerrefers to a quantity of matter that is homogeneous (all solid, liquid or
gas) throughout in both chemical
composition and physical structure.
False - answerTrue or false. A system cannot contain
one or more phases
Phase boundaries - answerIn the phase diagram, it is the line separating two different
phases.
Pure substance - answerone that is uniform and invariable in chemical composition. can
exist in more than one phase, but its chemical composition must be the same
in each phase.
Clausius Statement - answerIt is impossible for any system to operate in such a way
that the sole result would be an energy transfer by heat from a cooler to a hotter body.
True - answerTrue or False. A system consisting of air can be regarded as a pure
substance as
long as it is a mixture of gases; but if a liquid phase should form on cooling, the liquid
would
have a different composition from the gas phase, and the system would no longer be
considered
a pure substance.
Fourier's law - answerWhat is the governing law in the study of conductive heat
transfer?
