Final Flashcards

1
Q

Condensing is the change in state from a gas/vapor to a _________

A

Liquid

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2
Q

The ____________ gauge reads pressures above and below atmospheric pressure

A

Compound

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3
Q

Name the three types of heat transfer

A

Convection, conduction, and radiation

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4
Q

Define latent heat

A

Heat required to change a state of matter

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5
Q

A refrigeration compressor is designed to pump _________

A

Gas/vapor

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6
Q

What is it called when a solid changes to a vapor, bypassing the liquid state?

A

Sublimation

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7
Q

If changing water from 32F to 196F is it necessary to add latent heat

A

No

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8
Q

Name the three states in which most elements and compounds may exist

A

Solid, liquid, gas

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9
Q

Name the four components of the refrigeration system

A

Compressor, condenser, meter device, evaporator

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10
Q

When R-502 is at 248 PSIG, at what temperature will it begin to condense

A

111F (use PT Chart)

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11
Q

Convert 60C to Fahrenheit

A

140F = (1.8 x 60C) + 32

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12
Q

How many BTUs are in one ton of refrigeration

A

12,000

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13
Q

When an evaporator using R-12 is boiling the refrigerant at 26F, what is the suction pressure?

A

25 (use PT chart)

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14
Q

Sublimation is the changing of state from a solid to a liquid

A

False

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15
Q

By controlling the pressure on a liquid; different boiling temperature may be obtained

A

True

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16
Q

The specific heat of water is 0.5 BTUs

A

False

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17
Q

Heat is a form of energy

A

True

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18
Q

Copper will conduct heat better than glass

A

True

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19
Q

Heat transfer will take place between two objects of the same temperature

A

False

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20
Q

Magnetism is not a form of energy

A

False

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21
Q

Heat transfer is always from warm to cool

A

True

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22
Q

If the temperature of a refrigerant rises then the pressure will decrease, thus, it is inversely proportional

A

False

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23
Q

All liquids boil at the same temperature when under the same pressure

A

False

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24
Q

The formula to calculate BTUs is:
Q = specific heat x latent heat + temperature difference x weight

A

False

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25
Q

For every pressure applied to a liquid, there is a definite corresponding temperature at which it will boil or condense

A

True

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26
Q

Approximately how many inches of mercury (manifold gauge) are equal to standard atmospheric PSIG pressure at sea level

A

29.92

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27
Q

Approximately how many inches of mercury is a perfect vacuum

A

30

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28
Q

What are the two most common refrigerants used in residential air conditioning

A

R22 and R410A

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29
Q

The amount of heat in BTUs required to raise the temperature of a substance one degree Fahrenheit is

A

Specific heat

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30
Q

Water, ice, and steam are an example of

A

The states of matter

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31
Q

The heat required to melt one pound of ice at 32F to water at 32F equals

A

144 BTUs

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32
Q

Zero gauge pressure corresponds to an absolute pressure reading of

A

14.696 psia

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33
Q

Which component is considered the “heart” of the refrigeration system

A

Compressor

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34
Q

Heat, being a form of energy, cannot be

A

Destroyed

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35
Q

Condensing is the change in state from gas/vapor to a

A

Liquid

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36
Q

What is the proper condensing temperature for R22 that has a pressure of 226 PSIG

A

110 (PT chart)

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37
Q

The unit for measuring the quantity of heat is called the

A

BTU

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38
Q

How many BTUs per hour are equivalent to one ton of refrigeration

A

12,000

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39
Q

Ice will begin to melt when it’s sensible temperature rises above

A

0C

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40
Q

The heat used to change a liquid to a gas is called the latent heat of

A

Vaporization

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41
Q

What an evaporator using R12 is boiling the refrigerant at 26F, what is the suction pressure

A

25.4 psig (PT chart)

42
Q

All liquids boil at the same temperature when under the same pressure

A

False

43
Q

Heat transfer is always from warm to cool

A

True

44
Q

Hidden heat in refrigeration work is referred to as

A

Latent heat

45
Q

How many watts are in 1 kilowatt

A

1000

46
Q

Hidden heat is referred to as

A

Latent heat

47
Q

This component rejects heat in a refrigeration system

A

Condenser

48
Q

What color is a 30 pound cylinder of R22 refrigerant

A

Green

49
Q

The Fahrenheit scale is based on boiling water having a sea level temperature of

A

212F

50
Q

This gauge reads pressure above and below atmospheric pressure

A

Compound

51
Q

The heat required to melt one pound of ice at 32F to water at 32F equals BTUs

A

144

52
Q

The instrument used to measure the level or intensity of heat is called a

A

Thermometer

53
Q

The amount of heat in BTUs required to raise the temperature of one pound of a substance one degree Fahrenheit is defined as

A

Specific heat

54
Q

Magnetism is not a form of energy

A

False

55
Q

Absolute zero on a Fahrenheit scale equals

A

-460

56
Q

This substance takes up space and has weight

A

Matter

57
Q

Which of the following causes a change in the state of a substance

A

Latent heat

58
Q

A thermometer is used to measure

A

Sensible heat

59
Q

Absolute zero on the Fahrenheit scale equals ______F

A

-460

60
Q

Zero gauge pressure corresponds to an absolute pressure reading of

A

14.696 psia

61
Q

Heat is a form of energy

A

True

62
Q

Refrigerants should be operated at a temperature _______ their critical temperature

A

Below

63
Q

What agency do the letters EPA stand for

A

Environmental protection agency

64
Q

How many BTUs of heat per pound of water are required to vaporize 212F water

A

970

65
Q

Convert 75F to centigrade

A

23.88C = .555 x (F -32)

66
Q

How many BTUs of heat per pound of water are required to vaporize the water

A

970

67
Q

What color is a 30 pound cylinder of R410A refrigerant

A

Pink

68
Q

A liquid boils when its temperature is sufficiently raised or its pressure is sufficiently

A

Lowered

69
Q

When R502 is at 248 psig, at what temperature will it begin to condense

A

110F (PT chart)

70
Q

This substance takes up space and has weight

A

Matter

71
Q

For every pressure applied to a liquid, there is a definite corresponding temperature at which it will boil or condense

A

True

72
Q

What color is a refrigerant recovery cylinder

A

Yellow/gray

73
Q

Heat transfer will take place between two objects of the same temperature

A

False

74
Q

Absolute zero on the Celsius scale equals ______C

A

-273

75
Q

Given two objects of the same size, the one that is ____ will absorb more radiant heat

A

Painted black

76
Q

The instrument used to measure the level or intensity of heat is called a

A

Thermometer

77
Q

The Fahrenheit scale is based on boiling water having a sea level temperature of

A

212

78
Q

This component absorbs heat in a refrigeration system

A

Evaporator

79
Q

Absolute zero on the Celsius scale equals

A

-273

80
Q

What approximate temperature does brazing take place at

A

1200F

81
Q

Name the three types of heat transfer

A

Conduction, convection, radiation

82
Q

A thermometer is used to measure

A

Sensible heat

83
Q

Heat, being a form of energy, cannot be

A

Destroyed

84
Q

A refrigeration compressor is designed to pump

A

Vapor

85
Q

This component absorbs heat in a refrigeration system

A

Evaporator

86
Q

By controlling the pressure on a liquid, different boiling temperatures may be obtained

A

True

87
Q

The unit for measuring the quantity of heat is called the

A

BTU

88
Q

Ice will begin to melt when its sensible temperature rises above

A

32F

89
Q

Which of the following causes a change in state of a substance

A

Latent heat

90
Q

Convert 60C to Fahrenheit

A

140F = (1.8 x C) + 32

91
Q

The measure of energy content of a substance

A

Enthalpy

92
Q

Fluids which absorb heat and change state

A

Refrigerants

93
Q

288,000 BTU/24 hrs

A

One ton of refrigeration

94
Q

The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit

A

British thermal unit

95
Q

Measures pressures above and below atmospheric

A

Compound gauge

96
Q

A substances mass per unit of volume

A

Density

97
Q

The surrounding temperature of a motor

A

Ambient

98
Q

Also called relative density

A

Specific gravity

99
Q

Radiation, conduction, and convection

A

Methods of heat

100
Q

A form of energy

A

Heat