Thermodynamics (Properties of Working Substance) Flashcards
study of heat and work and those properties of substances that bear a relation to heat and work.
Thermodynamics
derived from Greek words theme, meaning “heat” an dynamics, meaning “strength” particularly applied to motion.
Thermodynamics
a substance to which heat can be stored and from which heat can be extracted.
Working Substance
a working substance whose chemical composition remains the same even if there is change in phase.
Pure substance
a working substance which remains in gaseous state during its operating cycle and whose equation of state is PV=mRT
Ideal gas
is the force per unit area. It may be described as a measure of the intensity force.
Pressure
pressure exerts by air as it has mass that is subjected to the action of the gravity.
Atmospheric Pressure
are instruments used to measure the pressure of the atmosphere.
Barometers
used to measure fluid pressure in a closed vessel.
Pressure gauges
Pressure gauges commonly used in the refrigeration industry are
Manometer and bourdon tube
type of gauge utilizes a column of liquid to measure the pressure, the height of the column indicating the magnitude of the pressure
Manometer
The liquid used in manometers is usually either
water or mercury
is understood to be the “total” or “true” pressure of a fluid
Absolute Pressure
is the pressure as indicated by a gage
Gage Pressure
is the pressure measured relative to absolute vacuum., that, absolute zero pressure
Absolute Pressure
is a pressure that is less than atmospheric pressure. It is also a negative pressure.
Vacuum Pressure
is the pressure measured relative to atmospheric pressure.
Gage pressure
a space that is devoid of matter, and in which the pressure is “zero”
Perfect Vacuum
is use to measure small and moderate pressure difference
Manometer
is commonly used mechanical pressure measurement device.
Bourdon Tube
is the degree of hotness or coldness of a substance or body
Temperature
measure the level of the thermal pressure of a body
Temperature
the most frequently used instrument for measuring temperature is
Thermometer
measures the temperature of high-temperature gases
Pyrometer
Heat will pass from one body to another when and only ______ exists between the two bodies
difference in temperature
maybe defined as the mass divided by the volume or reciprocal of specific volume.
Density
is the volume of a substance divided by its mass or reciprocal of density
Specific Volume
is the ratio of weight of an object to its volume.
Specific weight
Is the ratio of the density of any substance to the density of water which is known as the standard density
Specific Gravity
heat energy due to the movement of molecules within the brought about its temperature
Internal Energy
Constant Specific heat process
Internal Energy
also called molecular energy
Internal Energy
What is the sum of all of the microscopic forms of energy called?
Internal Energy
is the product of pressure and volume or specific volume
Flow Work
is the sum of internal energy and flow work. It is also a function of temperature
Enthalpy
is a measure of molecular disorder, or molecular randomness. As a system becomes more disordered, the positions of the molecules become less predictable and it increases
Entropy
is an extensive property of a system
Entropy
Occurs when a solid turns to a liquid.
Melting
occurs when a liquid turns to a solid.
Freezing or solidifying
occurs when a liquid turns to a gas
Vaporization
occurs when a gas (vapor) turns to a liquid
Condensation
Occurs when a solid turns to a gas
Sublimation
is simply a change in the system state
Process
is the point in which solid, liquid and vapor occur
Triple Point
heat energy that causes or accompanies a change in the temperature of a substance is called
Sensible heat
Heat energy that causes or accompanies a change in the phase of a substance is known as
Latent Heat
When the change occurs between the solid and liquid phases in either direction, the latent heat involved is known as
latent heat of fusion.
When the change occurs between the liquid and vapor phases in either direction, the latent heat involved is called
Latent heat of vaporization
