Propane Attendant Certification
PROPANE ATTENDANT CERTIFICATION | EXAM QUESTIONS
AND CORRECT ANSWERS | VERIFIED PROPANE SAFETY AND
HANDLING LATEST 2026/2027
PROPANE ATTENDANT CERTIFICATION
1. What is the chemical formula of propane?
A. CH4
B. C4H10
C. C2H6
D. C3H8
D. C3H8
Propane has three carbon atoms and eight hydrogen atoms. CH4 is methane and
C4H10 is butane.
2. At normal atmospheric pressure, propane boils at approximately:
A. 31°F (-0.5°C)
B. 32°F (0°C)
C. -259°F (-162°C)
D. -44°F (-42°C)
D. -44°F (-42°C)
Propane stays liquid at atmospheric pressure only below about -44°F, which is
why it vaporizes readily in almost any outdoor weather.
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, Propane Attendant Certification
3. Compared with air, propane vapor is:
A. Exactly the same weight, so it mixes evenly
B. About three times lighter, so it disperses upward
C. About half as heavy, so it rises quickly
D. About 1.5 times heavier, so it settles in low areas
D. About 1.5 times heavier, so it settles in low areas
Propane vapor has a specific gravity of about 1.52, so leaked vapor flows
downhill and collects in low spots.
4. One U.S. gallon of liquid propane weighs approximately:
A. 6.0 lb
B. 2.5 lb
C. 8.34 lb
D. 4.2 lb
D. 4.2 lb
Liquid propane weighs about 4.2 lb per gallon, roughly half the weight of water
(8.34 lb per gallon).
5. When liquid propane vaporizes, it expands to approximately how many
times its liquid volume?
A. 27
B. 270
C. 1,000
D. 50
B. 270
One volume of liquid propane produces roughly 270 volumes of vapor, which is
why a small liquid leak can create a large flammable cloud.
6. The flammable range of propane in air is approximately:
A. 12.5% to 74%
B. 5% to 15%
C. 2.1% to 9.5%
D. 0.5% to 1.5%
C. 2.1% to 9.5%
Propane will only ignite when mixed with air in a concentration of roughly
2.1% to 9.5%. Mixtures outside that range are too lean or too rich to burn.
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7. In its natural state, propane is:
A. Blue with a rotten-egg smell
B. Colorless with a sweet odor
C. Pale yellow and odorless
D. Colorless and odorless
D. Colorless and odorless
Pure propane has no color or smell. An odorant is added so leaks can be
detected.
8. The odorant most commonly added to propane is:
A. Methanol
B. Ethyl mercaptan
C. Ammonia
D. Hydrogen sulfide
B. Ethyl mercaptan
Ethyl mercaptan gives propane its distinctive rotten-egg or skunk-like smell.
9. The approximate heat content of one gallon of liquid propane is:
A. 91,500 BTU
B. 138,000 BTU
C. 2,500 BTU
D. 21,500 BTU
A. 91,500 BTU
A gallon of liquid propane contains about 91,500 BTU. The figure of about
2,500 BTU applies to one cubic foot of propane vapor.
10. The ignition temperature of propane in air is approximately:
A. 450°F to 500°F
B. 1,800°F to 2,000°F
C. 920°F to 1,120°F
D. 212°F to 300°F
C. 920°F to 1,120°F
Propane needs a source of roughly 920°F to 1,120°F to ignite, which is well
within the range of a match, spark or pilot flame.
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11. As long as some liquid remains in a cylinder, the pressure inside is
determined mainly by:
A. The amount of liquid in the cylinder
B. The age of the cylinder
C. The temperature of the liquid
D. The size of the cylinder
C. The temperature of the liquid
A nearly empty cylinder and a full one at the same temperature have the same
pressure. Pressure rises and falls with temperature.
12. At about 70°F (21°C), the vapor pressure of propane is approximately:
A. 110 psig
B. 25 psig
C. 375 psig
D. 250 psig
A. 110 psig
Propane at 70°F exerts roughly 110 psig. The pressure climbs to about 170 psig
at 100°F.
13. When liquid propane is warmed, it:
A. Contracts and takes up less space
B. Becomes a solid
C. Keeps exactly the same volume
D. Expands considerably, much more than water does
D. Expands considerably, much more than water does
Liquid propane expands significantly with temperature, so containers are never
filled liquid-full.
14. The specific gravity of liquid propane (water = 1.0) is approximately:
A. 0.85
B. 1.00
C. 0.51
D. 1.52
C. 0.51
Liquid propane is about half as heavy as water, so spilled liquid will float on
water while it vaporizes.
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PROPANE ATTENDANT CERTIFICATION | EXAM QUESTIONS
AND CORRECT ANSWERS | VERIFIED PROPANE SAFETY AND
HANDLING LATEST 2026/2027
PROPANE ATTENDANT CERTIFICATION
1. What is the chemical formula of propane?
A. CH4
B. C4H10
C. C2H6
D. C3H8
D. C3H8
Propane has three carbon atoms and eight hydrogen atoms. CH4 is methane and
C4H10 is butane.
2. At normal atmospheric pressure, propane boils at approximately:
A. 31°F (-0.5°C)
B. 32°F (0°C)
C. -259°F (-162°C)
D. -44°F (-42°C)
D. -44°F (-42°C)
Propane stays liquid at atmospheric pressure only below about -44°F, which is
why it vaporizes readily in almost any outdoor weather.
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, Propane Attendant Certification
3. Compared with air, propane vapor is:
A. Exactly the same weight, so it mixes evenly
B. About three times lighter, so it disperses upward
C. About half as heavy, so it rises quickly
D. About 1.5 times heavier, so it settles in low areas
D. About 1.5 times heavier, so it settles in low areas
Propane vapor has a specific gravity of about 1.52, so leaked vapor flows
downhill and collects in low spots.
4. One U.S. gallon of liquid propane weighs approximately:
A. 6.0 lb
B. 2.5 lb
C. 8.34 lb
D. 4.2 lb
D. 4.2 lb
Liquid propane weighs about 4.2 lb per gallon, roughly half the weight of water
(8.34 lb per gallon).
5. When liquid propane vaporizes, it expands to approximately how many
times its liquid volume?
A. 27
B. 270
C. 1,000
D. 50
B. 270
One volume of liquid propane produces roughly 270 volumes of vapor, which is
why a small liquid leak can create a large flammable cloud.
6. The flammable range of propane in air is approximately:
A. 12.5% to 74%
B. 5% to 15%
C. 2.1% to 9.5%
D. 0.5% to 1.5%
C. 2.1% to 9.5%
Propane will only ignite when mixed with air in a concentration of roughly
2.1% to 9.5%. Mixtures outside that range are too lean or too rich to burn.
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, Propane Attendant Certification
7. In its natural state, propane is:
A. Blue with a rotten-egg smell
B. Colorless with a sweet odor
C. Pale yellow and odorless
D. Colorless and odorless
D. Colorless and odorless
Pure propane has no color or smell. An odorant is added so leaks can be
detected.
8. The odorant most commonly added to propane is:
A. Methanol
B. Ethyl mercaptan
C. Ammonia
D. Hydrogen sulfide
B. Ethyl mercaptan
Ethyl mercaptan gives propane its distinctive rotten-egg or skunk-like smell.
9. The approximate heat content of one gallon of liquid propane is:
A. 91,500 BTU
B. 138,000 BTU
C. 2,500 BTU
D. 21,500 BTU
A. 91,500 BTU
A gallon of liquid propane contains about 91,500 BTU. The figure of about
2,500 BTU applies to one cubic foot of propane vapor.
10. The ignition temperature of propane in air is approximately:
A. 450°F to 500°F
B. 1,800°F to 2,000°F
C. 920°F to 1,120°F
D. 212°F to 300°F
C. 920°F to 1,120°F
Propane needs a source of roughly 920°F to 1,120°F to ignite, which is well
within the range of a match, spark or pilot flame.
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, Propane Attendant Certification
11. As long as some liquid remains in a cylinder, the pressure inside is
determined mainly by:
A. The amount of liquid in the cylinder
B. The age of the cylinder
C. The temperature of the liquid
D. The size of the cylinder
C. The temperature of the liquid
A nearly empty cylinder and a full one at the same temperature have the same
pressure. Pressure rises and falls with temperature.
12. At about 70°F (21°C), the vapor pressure of propane is approximately:
A. 110 psig
B. 25 psig
C. 375 psig
D. 250 psig
A. 110 psig
Propane at 70°F exerts roughly 110 psig. The pressure climbs to about 170 psig
at 100°F.
13. When liquid propane is warmed, it:
A. Contracts and takes up less space
B. Becomes a solid
C. Keeps exactly the same volume
D. Expands considerably, much more than water does
D. Expands considerably, much more than water does
Liquid propane expands significantly with temperature, so containers are never
filled liquid-full.
14. The specific gravity of liquid propane (water = 1.0) is approximately:
A. 0.85
B. 1.00
C. 0.51
D. 1.52
C. 0.51
Liquid propane is about half as heavy as water, so spilled liquid will float on
water while it vaporizes.
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