Book 2: 4-16 - "Refrigerants"

Question 1

Liquid refrigerants absorb heat by evaporating at a low temperature and pressure and then give up that heat by _____ at a higher temperature and pressure.
Select one:

A. Regenerating

B. Condensing

C. Fusing

D. Evaporating

E. Absorbing

Answer 1

B. Condensing

Question 2

Refrigerants that are highly flammable and highly toxic belong to Group:
Select one:

A. B2

B. B3

C. B1

D. A2

E. A3

Answer 2

B. B3

Question 3

The saturation temperature (boiling/condensing temperature) of a liquid in a closed vessel can be raised or lowered by altering the _____ the vessel.
Select one:

A. Temperature in

B. Volume of

C. Pressure on

D. Density in

E. Pressure in

Answer 3

E. Pressure in

Question 4

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

A. Density

B. Miscibility

C. Enthalpy

D. Moisture reaction

E. Leakage tendency

Answer 4

B. Miscibility

Question 5

What is the boiling temperature of R-134a (Freon 34a)at atmospheric conditions?
Select one:

A. 3.6°C (38.5°F)

B. -33.3°C (-27.94°F)

C. -26.1°C (-14.98°F)

D. -40.8°C (-41.44°F)

E. 47.6°C (117.68°F)

Answer 5

C. -26.1°C (-14.98°F)

Question 6

What is the boiling temperature of R-22 (Freon 22) at atmospheric conditions?
Select one:

A. -40.8°C (-41.44°F)

B. 47.6°C (117.68°F)

C. 3.6°C (38.5°F)

D. -26.1°C (-14.98°F)

E. -33.3°C (-27.94°F)

Answer 6

A. -40.8°C (-41.44°F)

Question 7

Which one of the following factors affect the leakage tendency of a refrigerant?
Select one:

A. Density

B. Specific volume

C. Enthalpy

D. Temperature

E. Miscibility

Answer 7

A. Density

Question 8

Moisture in the refrigerant may lead to:
Select one:

A. Over cooling of the refrigerant

B. Ice formation between the valve and valve seat of the regulating or expansion valve

C. High pressure in the evaporator

D. Low temperature in the condenser

E. Ice forming in the condenser

Answer 8

B. Ice formation between the valve and valve seat of the regulating or expansion valve

Question 9

In an ideal situation the refrigerating effect of a refrigerant is equal to the _____ of the refrigerant.
Select one:

A. Latent heat of fusion

B. Sensible heat of fusion

C. Temperature of evaporation

D. Latent heat of evaporation

E. Temperature of fusion

Answer 9

A. Latent heat of fusion

Question 10

Which of the following refrigerants is not miscible with oil?
Select one:

A. Freon 11 (R-11)

B. Freon 12 (R-12)

C. Ammonia (R-717)

D. Freon 22 (R-22)

E. Freon 134a (R-134a)

Answer 10

C. Ammonia (R-717)

Question 11

What must be provided when using a halide leak detector or when soldering or brazing on a refrigeration system?
Select one:

A. Sufficient flow from the leak source

B. A Class ABC Fire Extinguisher

C. Adequate ventilation

D. Cool refrigerant temperatures

E. Sufficient detectable odour from the refrigerant

Answer 11

C. Adequate ventilation

Question 12

Refrigerants are classified in the Canadian Standards Association B52-05 Mechanical Refrigeration Code by their toxicity and flammability into the following _____ groups.
Select one:

A. Four

B. Six

C. Five

D. Two

E. Three

Answer 12

B. Six

Question 13

Liquid refrigerants are fluids that, at atmospheric pressure, have a boiling point considerably:
Select one:

A. Lower than that of water

B. High than that of water

C. Higher than that of oxygen

D. Lower than that of oil

E. Lower than that of oxygen

Answer 13

A. Lower than that of water

Question 14

Refrigerants that are non-toxic and non-flammable belong to Group:
Select one:

A. A1

B. B2

C. A2

D. A3

E. B1

Answer 14

A. A1

Question 15

Refrigerants that are highly flammable with low toxicity belong to Group:
Select one:

A. B2

B. A2

C. B1

D. B3

E. A3

Answer 15

E.
A3

Question 16

The important physical properties of a refrigerant include all except:
Select one:

A. Leakage tendency

B. Toxicity

C. Enthalpy

D. Moisture reaction

E. Odour

Answer 16

C. Enthalpy

Question 17

The condition known as “standard condition” indicates a standard evaporator temperature of:
Select one:

A. -10°C (14°F)

B. -15°C (5°F)

C. -30°C (-22°F)

D. 30°C (86°F)

E. 15°C (59°F)

Answer 17

B. -15°C (5°F)

Question 18

Thermodynamic properties directly affect the movement of heat. Which of these is NOT a thermodynamic property?
Select one:

A. Leakage tendency

B. Enthalpy

C. Pressure

D. Volume

E. Density

Answer 18

A. Leakage tendency

Question 19

Which one of the following factors affect the leakage tendency of a refrigerant?
Select one:

A. Temperature

B. Viscosity

C. Specific volume

D. Enthalpy

E. Miscibility

Answer 19

B. Viscosity

Question 20

An ideal refrigerant should NOT have which of the following characteristics:
Select one:

A. A fairly low condensing pressure

B. A non-flammable and non-explosive nature when mixed with air

C. A low boiling point at atmospheric pressure

D. A low latent heat capacity

E. A non-poisonous nature

Answer 20

D. A low latent heat capacity