Chapter 9 exam
there are ____ divisions in the classification for flammability of refrigerants
4
according to the ASHRAE calssification for refrigerants the classification for the least toxic and least flammable refrigerants is
A1
due to their high ozone depletion potential, ____ refrigerants were targeted first for phaseout by the Montreal protocol
CFC
service technicians can safely use formulas and tables to mix their own refrigerant blends. true or false
False
because they cannot be mixed with mineral oils, ____ refrigerants use synthetic oils for lubrication
HFC
if a refrigernat belongs to the 700 series in the refrigerant system, then it is ____
Inorganic
how many times can a refrigerant be used?
Once
the ODP scale compares the destructive potential of different chemicals to the destructive potential of
R-11
which zeotropic refrigerants blend is used as a replacement for R-22 in air conditioning applications but operates at higher temperature and pressure?
R-410A
a pressure-temperature curve shows that a pressure and temperature are ____ in a refrigeration system
directly related
a presure-tempture curve shows that pressure and temperature are ____ in a refrigeration system.
directly related
also refed to as chemical refrigeration or open-cycle refrigeration _____ refrigeration systems use a refrigerant only once
expendable
HCFCS have an ODP rating of 0. true or false
false
HCFCs have an ODP rating of 0. True or false
false
HFCs were the first of refrigerant to be produced. true or false
false
carbon is classified as an organic refrigerant (600 series). true or false
false
cylinder color-coding is a requirement for manufactures, so technicians do not need to check labels. True or false
false
service technicians can safely use formulas and tables to mix their own azeotropic refrigerant blends. true or false
false
the ODP scale compares the destructive potential of different chemicals to the destructive potential of R-12. true or false
false
the refrigerant temperature in the evaporator is the same as the evaporator temperature when the unit is running. true or false
false
there are six divisions in the classification for flammability of refrigerants. true or false
false
the separation of the individual refrigerants in a zeotropic blend during phase change is known as
fraction
the separation of the individual refrigerants in a zeotropic blend during phase change is known as
fractionation
if a refrigerant belongs to the 700 series in the refrigerant numbering system, then it is______
inorganic
Refrigerant blends that react similarly to zoetrope's but responds over a smaller range of boiling and condensation points are called
near-azeotropes
the _____ layer is a thin layer in the earths upper atmosphere that helps filer ultraviolet rays
ozone
the lowest temperature at which a lubricant will flow is called the
pour point
the cylinder color code for R-134a is
sky blue
if heat is added to a saturated vapor and raises the vapors temperature above its boiling point, heat is referred to as
superheat
if heat is added to a saturated vapor and raises the vapors temperature above its boiling point, the heat is referred to as_____
superheat
when a refrigeration unit is off, the temperature of the condenser is ____ the temperature of the refrigerant
the same as
the ability of a refrigerant to be harmful or lethal with exposure is referred to as its
toxicity
R-134 has been used as a replacement refrigerant for systems that use R-12. true or false
true
R-22 and R-123 are classified as HCFC refrigerants. true or false
true
a higher coefficient of performance that a refrigerant produces its refrigeration effect more efficiently. true or false
true
a refrigerant blend containing an HCFC and CFC is considered a CFC. true or false
true
a refrigerant blend containing an HCFC and a CDC is considered a CFC. true or false
true
in a zeotropic refrigerant with the lowest boiling point boils first. true or false
true
