RFRG 6006 - Refrigerants (Chp 16)

Question 1

The refrigerating effect of a refrigerant is:

A) Greater than its latent heat of vaporization
B) Equal to its specific volume
C) Equal to its latent heat of vaporization
D) Less than its latent heat of vaporization
E) Equal to its specific heat capacity

Answer 1

C) Equal to its latent heat of vaporization

Question 2

Which of the following characteristics is common in all of the group B refrigerants?

A) Low flammability
B) Average flammability
C) High flammability
D) High toxicity
E) Low toxicity

Answer 2

D) High toxicity

NOTE:group B refrigerants?

Question 3

The ability of a refrigerant to be dissolved into oil and vice versa is called:

A) Density
B) Moisture reaction
C) Enthalpy
D) Miscibility
E) Leakage tendency

Answer 3

D) Miscibility

NOTE;dissolved into oil and vice versa

Question 4

Which of the following is not a physical property of refrigerants?

A) Leakage tendency
B) Toxicity
C) Oxidization
D) Odour
E) Explosiveness

Answer 4

C) Oxidization

NOTE:not a physical property of refrigerants

Question 5

Molecular mass is a dependent factor in which of the following physical properties of a refrigerant?

A) Leakage tendency
B) Explosiveness
C) Miscibility
D) Toxicity
E) Flammability

Answer 5

A) Leakage tendency

NOTE: MOLECULAR MASS

Question 6

Group “A1” refrigerants as found in the current code are:

A) Toxic and non-flammable
B) Non-flammable and non-toxic
C) Low-flammable and toxic
D) High-toxic and flammable
E) Low-toxic and flammable

Answer 6

B) Non-flammable and non-toxic

Question 7

The standard refrigeration cycle is used to compare refrigerants and machines operating under comparable conditions. These standard conditions are:

A) 30°C and atmospheric pressure
B) 103°C and atmospheric pressure
C) 30°C for the condenser and -15°C for the evaporator
D) -30°C for the condenser and 15°C for the evaporator
E) 103 kPa and ambient temperature

Answer 7

C) 30°C for the condenser and -15°C for the evaporator

Question 8

The property which must be known to calculate the size of control valves piping, etc. is:

A) Density
B) Refrigerating effect
C) Boiling point
D) Specific volume
E) Enthalpy

Answer 8

A) Density

NOTE:calculate the size of control valves piping, etc. is:

Question 9

R-134a (1, 1, 1, 2 - tetrafluoroethane) is non-toxic and non-flammable. Which of the following group does it belong to?

A) Group A1
B) Group B4
C) Group A2
D) Group A3
E) Group B2

Answer 9

A) Group A1

NOTE:R-134a (1, 1, 1, 2 - tetrafluoroethane)

Question 10

The practical refrigerating effect of a refrigerant is:

A) Equal to its latent heat of vaporization
B) Equal to its specific volume
C) Greater than its latent heat of vaporization
D) Equal to its specific heat capacity
E) Less than its latent heat of vaporization

Answer 10

E) Less than its latent heat of vaporization

NOTE: practical refrigerating effect of a refrigerant

Question 11

According to the refrigeration tables which of the following is the corresponding temperature at an absolute pressure of 103.05 kPa for R717?

A) 115°C
B) 10°C
C) -75°C
D) -33°C
E) -101°C

Answer 11

D) -33°C

Question 12

Which refrigerant is corrosive to copper, flammable, readily absorbs in water, is toxic, has the highest refrigerating effect?

A) Dichlorotetraflouoroethane R-114
B) Ammonia R-717
C) Freon R 134
D) Freon R-12
E) Freon R-22

Answer 12

B) Ammonia R-717