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WorksheetsACR-101 Final Review
Total questions: 108
Worksheet time: 2hrs 48mins
Temperature is defined as
heat content.
the level of heat.
the British thermal unit.
the absence of cold.
For water to boil at 212°F, the standard atmospheric pressure should be
14.696 psig, or 29.92 in Hg.
0 psia, or 29.99 in Hg.
0 psig, or 0.92 in Hg.
14.696 psia, or 29.92 in Hg.
Fahrenheit, Celsius, Rankine, and Kelvin are
temperature scales.
pressure scales.
Btu measurements.
heat transfer methods.
Under standard conditions, water freezes at
0°C.
10°C.
20°C.
32°C.
Molecular motion stops at
212°F.
-32°F.
-460°F.
0°F.
One British thermal unit will raise the temperature of
1 gallon of water 1°F.
1 pound of water 1°F.
1 pound of water 1°K.
1 gallon of water 1°C.
In which direction does heat flow?
From a cold substance to a cold substance
From a cold substance to a warm substance
From a warm substance to a warmer substance
From a warm substance to a cold substance
Heat transfer from molecule to molecule is known as
radiation.
convection.
conduction.
evaporation.
An increase in sensible heat causes
a higher thermometer reading.
a lower thermometer reading.
no change of the thermometer reading.
ice to melt.
Latent heat causes
a higher thermometer reading.
temperature to rise.
a change of state.
temperature to fall.
Heat that is transferred by moving in a medium such as air or water is known as
radiation.
convection.
conduction.
evaporation.
Heat that is transferred through space without heating the space and that heats the first solid object that it strikes is known as
radiation.
convection.
conduction.
evaporation.
Specific heat is the amount of heat necessary to raise the temperature of 1 lb of which substance 1°F?
Water
Air
Refrigerant
Any substance
Atmospheric pressure at sea level under standard conditions is ____ inches of mercury (Hg) or ____ pounds per square inch absolute (psia).
14.696, 29.92
29.92, 14.696
0.92, 0
29.99, 0
80°F is the equivalent of
26.7°C.
35.4°C.
41.2°C.
22°C is the equivalent of
26.7°F.
34.5°F.
71.6°F.
81.4°F.
To change from psig to psia, you must
add 29.92 to psig.
add 14.696 to psig.
subtract 0.925 from psig.
subtract 3.1416 from psig.
10 in. Hg is equivalent to
5 psia.
20 psia.
25 psia.
30 psia.
2 psia is equivalent to
29 in. Hg.
28 in. Hg.
27 in. Hg.
26 in. Hg.
125 psig is equivalent to
14.696 psia.
135 psia.
139.7 psia.
A barometer is used to measure
atmospheric pressure.
gauge pressure.
absolute pressure.
stratospheric pressure.
What size heater will be required to heat the water in a swimming pool from 70°F to 72°F in 1 hour if the appliance is 100% efficient and the pool holds 20,000 gallons of water?
166,000 Btu/h
332,000 Btu/h
86,000 Btu/h
224,000 Btu/h
What size heater will be required to heat the water in a swimming pool from 70°F to 80°F in 5 hours if the appliance is 100% efficient and the pool holds 20,000 gallons of water?
166,000 Btu/h
830,000 Btu/h
332,000 Btu/h
1,660,000 Btu/h
How much pressure is exerted downward by a 50-pound solid object that has a base area of 10 square inches?
50 psi
25 psi
10 psi
5 psi
If a 100-lb solid object exerts a downward force of 200 psi, what is the area of the object's base?
0.25 square inches
0.50 square inches
2 square inches
4 square inches
Matter is a substance that occupies space and has
color.
texture.
temperature.
mass.
Solid, liquid, and gas are the most common
states of matter.
specific volumes.
gravitational forces.
fossil fuels.
In what direction does a solid exert force?
Outward
Upward
Downward
Outward, upward, and downward
In what direction does a liquid exert force?
Outward
Upward
Downward
Downward and outward
Vapor exerts pressure in what direction?
Outward
Upward
Downward
Outward, upward, and downward
The mass per unit volume of a substance is defined as
mass.
density.
work.
specific gravity.
The density of a substance compared to the density of water is known as
specific gravity.
specific volume.
mass.
weight.
The volume occupied by 1 pound of a fluid is known as
specific gravity.
specific volume.
mass.
weight.
The density of tungsten is 1210 lb/ft³. What would be its specific volume?
0.0826 ft³/lb
0.00826 lb/ft³
0.000826 lb/ft³
0.000826 ft³/lb
The specific volume of red brass is 0.001865 ft3/lb. What would be its density?
53.61 lb/ft3
56.19 lb/ft3
536.19 lb/ft3
536.19 ft3/lb
Aluminum has a density of 171 lb/ft³. What would be its specific gravity?
2.74
27.4
4.72
47.2
Four pounds of a gas occupy 10 ft³. What would be its density and specific gravity?
0.4 ft³/lb
0.4 lb/ft³
4.0 lb/ft³
4.0 ft³/lb
Whose law states that the volume of a gas varies inversely with the absolute pressure, as long as the temperature remains constant?
Charles’
Boyle’s
Newton’s
Dalton’s
At a constant pressure, how does a volume of gas vary with respect to the absolute temperature?
It will expand when it is heated or cooled.
It will remain constant.
It will expand when cooled or contract when heated.
It will expand when heated or contract when cooled.
Whose law states that the total pressure of a confined mixture of gases is the sum of the pressures of each of the gases in the mixture?
Charles’
Boyle’s
Newton’s
Dalton’s
What are the two types of energy most frequently used or considered in this industry?
Solar and fossil fuels
Nuclear and wind
Nuclear and solar
Wind and solar
The time rate of doing work is called
weight.
distance.
power.
force.
Force × distance is used to determine
weight.
work.
power.
volume.
If an air-conditioning compressor weighing 300 lbs had to be lifted 4 ft to be mounted on a base, how much work, in ft-lb, must be done?
12,000 lb/ft³
1200 ft²/lb
120 foot-pounds
1200 foot-pounds
How many watts of electrical energy are equal to 1 hp?
1492
746
74.6
373
What unit of energy does the power company charge the consumer for?
Kilowatt-hour
Watt-hour
Btu/h
Therm
If 3000 ft³ of air is crossing an evaporator coil and is cooled from 75°F to 55°F, what would be the volume of air, in ft³, exiting the evaporator coil?
288.7 ft³
28.7 ft³
2887.8 ft³
1392.2 ft³
A gas is compressed inside a compressor’s cylinder. When the piston is at its bottom dead center, the gas is initially at 10 psig, 65°F, and 10.5 in³. After compression and when the piston is at top dead center, the gas is 180°F and occupies 1.5 in³. What would be the new pressure of the gas in psig?
196
19.6
1.96
1960
How many Btu/h would be produced in a 12-kW electric heater?
40,956 Btu/h
400,956 Btu/h
495 Btu/h
How many Btu of heat can be produced by 4 kWh of electricity?
136,520 Btu/h
136 Btu/h
1365 Btu/h
13,652 Btu/h
An object weighs less on the moon than on earth because:
the moon has less gravity than earth
the moon is farther from the sun
the moon has more air resistance
the moon is made of lighter materials
Information regarding the specific volume of gases is important to the designer of air-conditioning, heating, and refrigeration equipment because:
it helps in determining the size and capacity of equipment needed for efficient operation.
it indicates the color of the gases used in the system.
it determines the electrical wiring required for the equipment.
it specifies the maintenance schedule for the equipment.
Horsepower is described as a measure of power, and the three quantities needed to determine horsepower are?
force, distance, and time.
mass, velocity, and acceleration.
voltage, current, and resistance.
pressure, area, and volume.
Specific volume and density are related to each other as:
Specific volume is the inverse of density.
Specific volume is equal to density.
Specific volume is the sum of density and volume.
Specific volume is unrelated to density.
The law of conservation of energy states that:
Energy cannot be created or destroyed, only transformed from one form to another.
Energy can be created but not destroyed.
Energy is always lost during transformations.
Energy can only be destroyed, not created.
Heat energy flows from a substance at -125°F to a substance at -175°F because:
heat always flows from a warmer substance to a colder substance
heat always flows from a colder substance to a warmer substance
heat does not flow between substances at negative temperatures
heat energy only flows at temperatures above 0°F
Magnetism can be used to help convert electrical energy to mechanical energy by:
using magnetic fields to create motion in electric motors
heating wires to produce light
storing energy in batteries
transmitting signals through wires
A refrigeration system that maintains a space at a temperature between 35°F and 40°F would be classified as what type of system?
High-temperature
Medium-temperature
Low-temperature
Ultra-low-temperature
A refrigeration system that is intended to provide comfort cooling would be classified as what type of system?
High-temperature
Medium-temperature
Low-temperature
Ultra-low-temperature
One ton of refrigeration is the equivalent of moving heat at a rate of
1200 Btu/min
12,000 Btu/min
1200 Btu/h
12,000 Btu/h
The basic refrigeration cycle can best be described as a
non-repeating, vapor-compression cycle.
non-repeating, vapor-combustion cycle.
repeating, vapor-compression cycle.
repeating, vapor-combustion cycle.
Saturated R-410A at a pressure of 95 psig will change at a temperature of
29°F.
95°F.
118°F.
295°F.
The evaporating pressure for R-22 is 76 psig and the evaporator outlet temperature is 58°F. What is the evaporator superheat?
13°F
45°F
58°F
132°F
The state of the refrigerant at the inlet of the evaporator is approximately
50% liquid and 50% vapor.
75% liquid and 25% vapor.
100% superheated vapor.
100% subcooled liquid.
The state of the refrigerant at the outlet of the evaporator should be
50% liquid and 50% vapor.
75% liquid and 25% vapor.
100% superheated vapor.
100% subcooled liquid.
The state of the refrigerant at the outlet of the condenser should be
50% liquid and 50% vapor.
75% liquid and 25% vapor.
100% superheated vapor.
100% subcooled liquid.
If the evaporator outlet temperature on an R-410A system is 50°F and the evaporator superheat is 10°F, what is the evaporating pressure of the refrigerant in this system?
143 psig
118 psig
84 psig
62 psig
If the evaporating pressure was 76 psig for R-22 and the compressor inlet temperature was 65°F, what would be the total superheat entering the compressor?
11°F
21°F
10°F
20°F
When an air-conditioning system operates in a vacuum, which of the following is true?
Air will leak out of the system
Refrigerant will leak out of the system
Air will be pulled out of the system
Refrigerant will be pulled into the system
The condensing pressure is 417.4 psig for R-410A and the condenser outlet temperature is 108°F. How much subcooling is there in the condenser?
7°F
12°F
21°F
42°F
The expansion device is responsible for
controlling the operation of the compressor.
controlling the subcooling.
metering refrigerant flow into the evaporator.
storing refrigerant for future use.
A properly operating compressor should have __________ at its inlet and __________ at its outlet.
100% vapor, 100% vapor
100% liquid, 100% liquid
100% vapor, 100% liquid
100% liquid, 100% vapor
Of the following compressors, which is a residential compressor that is forgiving when it comes to having liquid entering it?
The reciprocating compressor
The scroll compressor
The rotary compressor
The screw compressor
Which of the following statements is true with regards to reciprocating and rotary compressors?
Rotary and reciprocating compressors with similar capacities are similarly sized.
Both rotary and reciprocating compressors are equipped with suction and discharge valves.
Both rotary and reciprocating compressors can be opened for service.
For compressors with similar capacities, rotary compressors are smaller than reciprocating compressors.
The color-coding for an R-22 refrigerant cylinder is
white.
green.
orange.
brown.
The color-coding for an R-404A refrigerant cylinder is
white.
green.
orange.
brown.
Of the following refrigerants, which has the lowest global warming potential (GWP)?
R-410A
R-134a
R-407C
R-1234yf
The three processes commonly used to describe refrigerant handling are
recovering
recycling
reclaiming
reusing
replacing
The term that is used to quantify the amount of heat absorbed in the evaporator is
total heat of rejection.
net refrigeration effect.
heat of compressor.
adiabatic expansion.
The three regions on a pressure/enthalpy chart are
high-pressure, low-pressure, critical pressure.
superheated vapor, superheated liquid, depressurized liquid.
superheated vapor, subcooled liquid, saturated.
high-pressure liquid, low-pressure gas, low-pressure liquid.
The thumbprint-shaped region on the pressure/enthalpy chart is called the
saturation curve.
saturation cycle.
superheated curve.
superheated region.
One of the challenges of plotting an R-407C system on a pressure/enthalpy chart is that this refrigerant
is a single-compound refrigerant with one pressure for each temperature.
has a significant temperature glide.
is a binary blend of R-32 and R-125, making it unstable.
is easily mistaken for R-134a and R-410a.
The typical temperature inside the fresh-food compartment in a domestic refrigerator is
25°F to 30°F.
30°F to 35°F.
35°F to 40°F.
40°F to 45°F.
The operating condition for the single compressor in a household refrigerator is the lowest box temperature, which is typically
0°F
-20°F
20°F
40°F
When the air temperature in a domestic freezer is 0°F, the plate-type evaporator temperature may be as low as
-30°F.
-12°F.
-6°F.
0°F.
Typical head pressures should correspond to a condensing temperature higher than room temperature at design operating conditions.
5°F to 10°F
10°F to 15°F
20°F to 35°F
35°F to 45°F
Frost accumulates on the evaporators of forced-draft refrigerators because
they are generally located within a house.
they are generally located in high-humidity areas.
they are low-temperature appliances.
there is a heat exchange with the suction line.
When unfrozen product is placed in the freezer compartment of a domestic refrigerator/freezer, the product
will freeze slowly and large ice crystals will likely form.
will freeze slowly and small ice crystals will likely form.
will freeze quickly and large ice crystals will likely form.
will freeze quickly and small ice crystals will likely form.
The compressors used in domestic appliances typically range in size from
1/20 horsepower to 1/10 horsepower.
1/10 horsepower to 1/3 horsepower.
1/3 horsepower to 1/2 horsepower.
1/2 horsepower to 1 horsepower.
The flow through the capillary tube metering device is determined by the
outside diameter of the tubing and its inside (bore) diameter.
inside (bore) diameter and the appliance voltage.
outside diameter of the tubing and the length of the tubing.
inside (bore) diameter and the length of the tubing.
A manual defrost system is most likely to be found on what type of system?
An appliance with an induced-draft evaporator
An appliance with an induced-draft condenser
An appliance with a natural-draft evaporator
An appliance with two parallel compressors
The capillary tube metering device is often fastened where to improve heat exchange and system performance?
Surface of the evaporator
Compressor discharge line
Compressor suction line
Liquid line
The doors of domestic appliances are typically removed when the appliance is disposed of to prevent
other individuals from using the appliance.
someone from getting trapped inside the appliance.
mold from forming inside the appliance.
water from accumulating inside the appliance.
Condensers in domestic refrigerators and freezers are
air-cooled.
water-cooled.
oil-cooled.
brine-cooled.
What is the name given to the heaters that are located around the doors of the appliance to prevent sweating?
Defrost heaters
Oil heaters
Condensate heaters
Mullion heaters
Which of the following statements is true regarding the interior surfaces of most refrigerators and freezers?
They are made of metal, are easy to clean, and can become brittle when cold.
They are made of plastic, are easy to clean, and can become brittle when cold.
They are made of metal, are difficult to clean, and can become brittle when cold.
They are made of plastic, are difficult to clean, and can become brittle when cold.
The adjustment device used for low atmospheric pressure conditions is called the
altitude thermostatic adjustment control.
automatic thermostatic adjustment control.
altitude electrostatic adjustment control.
automatic electrostatic adjustment control.
The ice-making process in a domestic freezer is typically controlled by
temperature.
demand.
time.
pressure.
Depending on the type of condenser, the condenser saturation temperature for a domestic appliance located in a cool, 65°F room will likely be between
130°F and 140°F
115°F and 125°F
100°F and 110°F
85°F and 95°F
When should gauges be installed on a domestic refrigerator or freezer?
Whenever the system is serviced
Each time the water filter is replaced
Once a year to check the refrigerant charge
Only when absolutely necessary
A dirty condenser coil on a domestic refrigerator will cause the
appliance’s operating pressures to rise.
appliance’s operating pressures to drop.
suction pressure to rise and the discharge pressure to drop.
discharge pressure to rise and the suction pressure to drop.
Forced-draft evaporators are characterized as being
physically small with small quantities of air moving through them.
physically large with small quantities of air moving through them.
physically small with large quantities of air moving through them.
physically large with large quantities of air moving through them.
The type of compressor typically found on a domestic appliance is
welded, semihermetic.
welded, hermetic.
flanged, semihermetic.
flanged, hermetic.
On a domestic appliance with a mechanical draft condenser,
the compressor cycles on and off with the evaporator fan motor.
the compressor cycles on and off with the condenser fan motor.
the condenser fan motor cycles on and off with the evaporator fan motor.
the condenser fan motor, evaporator fan motor, and compressor cycle on and off together.
The door switch on a domestic appliance controls the operation of the
compressor.
condenser fan motor.
evaporator fan motor.
defrost cycle.
Describe the Refrigeration cycle. Ensure you explain where the change of state occurs and the function of each major component in the cycle. Explain where superheating and subcooling occur and define what each term means.
Label the refrigeration cycle:
Condenser
Liquid Line
Suction Line
Discharge Line
Evaporator
Compressor
Metering Device
Expansion Line
Label the refrigeration cycle:
H/P, H/T Liquid
H/P, H/T Vapor
L/P, L/T Liquid
L/P, L/T Vapor
