NITROX EXAM GUIDE QUESTIONS
WITH CORRECT ANSWERS
The nitrogen in the air you are breathing limits what? -Answer-The nitrogen in the air
limits the depth to which you can dive, the same time you can stay at depth, and the
number of dives you can make in a day.
What are the several names given to the gas mixture that is higher in oxygen and
lower in nitrogen? -Answer-Oxygen-Enriched Air,
Enriched Air Nitrox,
Nitrox
When diving, what causes the additional nitrogen to be dissolved in our tissues? -
Answer-When diving, the increased pressure of depth causes additional nitrogen to
be dissolved in our tissues.
In 1878, Paul Bert established that nitrogen, liberated as bubbles following sudden
decompression, was the cause of what? -Answer-Decompression sickness
Credit for developing and introducing nitrox diving techniques for standard scuba
goes to whom? -Answer-Dr. Morgan Wells
In what year did NAUI officially endorse nitrox training by NAUI instructors? -Answer-
1992
List 4 advantages of using nitrox -Answer-Extend bottom time
Shorten required surface interval
Safety margin
Less physically tired (fatigue)
Nitrox provides the greatest advantages for dives in what depth range? -Answer-15-
33 meter (50-100 foot) depth range
The "x" in EANx is often replaced with what? -Answer-Oxygen percentage
What compares the quantity of the component gas to a total of 100? What compares
it to 1? -Answer-Percentage.
Fraction.
Each of the individual components in a gas mixture will exert its chemical or physical
effects independently, according to what? -Answer-Its proportion in the mixture
Oxygen is what percentage of atmospheric air?
Nitrogen? -Answer-21%;
79%
The symptoms of nitrogen narcosis parallel those often seen in what? -Answer-
Alcohol intoxication
, If we heat a gas, we are adding _________, increasing the speed of the molecules
and the force of the impacts -Answer-Energy
Which law states: "At a constant temperature, the volume of a gas varies inversely
with absolute pressure, while the density of a gas varies inversely with absolute
pressure?" -Answer-Boyle's Law
Which law states: "The amount of any given gas that will dissolve in a liquid at a
given temperature is a function of the partial pressure of the gas that is in contact
with the liquid and the solubility coefficient of the gas in the particular liquid?" -
Answer-Henry's Law
What is the portion of the total gas pressure exerted by a single gas in a mixture of
gases? -Answer-Partial Pressure
Which law states: "The total pressure exerted by a mixture of gases is equal to the
sum of the pressures that would be exerted by each of the gases if it alone were
present and occupied volume."? -Answer-Dalton's Law
Each __________ that you descend in the ocean adds another atmosphere of
pressure to the one atmosphere of surface pressure. -Answer-10 meters (33 feet)
When you are at a depth of 20 meters of seawater (msw)/66 feet of seawater (fsw),
the absolute pressure is what? -Answer-3 ata
To convert depth to absolute pressure, you first find the water (hydrostatic) pressure
in atmospheres and then add what? -Answer-One atmosphere for the sea level air
pressure
To determine the partial pressure of a gas in a mixture, you multiply what two
numbers? -Answer-Gas fraction
Absolute pressure
Using the Oxygen Partial Pressure at Depth table, what is PO2 of EAN34 at a depth
of 24 msw (80fsw)? -Answer-1.16 ata
A stuporous condition characterized by impaired mental and physical performance
and changes in mood and behavior is known as _____. -Answer-Nitrogen narcosis
The mechanisms of nitrogen narcosis are thought to be similar to what? -Answer-
Gases used in anesthesia
What are the terms for absorption and elimination of nitrogen during a dive? -
Answer-Ingassing and offgassing
List the signs and symptoms of decompression sickness? -Answer-Excessive fatigue
weakness and tingling in limbs
limb and join pain and dysfunction
skin rashes and itching
WITH CORRECT ANSWERS
The nitrogen in the air you are breathing limits what? -Answer-The nitrogen in the air
limits the depth to which you can dive, the same time you can stay at depth, and the
number of dives you can make in a day.
What are the several names given to the gas mixture that is higher in oxygen and
lower in nitrogen? -Answer-Oxygen-Enriched Air,
Enriched Air Nitrox,
Nitrox
When diving, what causes the additional nitrogen to be dissolved in our tissues? -
Answer-When diving, the increased pressure of depth causes additional nitrogen to
be dissolved in our tissues.
In 1878, Paul Bert established that nitrogen, liberated as bubbles following sudden
decompression, was the cause of what? -Answer-Decompression sickness
Credit for developing and introducing nitrox diving techniques for standard scuba
goes to whom? -Answer-Dr. Morgan Wells
In what year did NAUI officially endorse nitrox training by NAUI instructors? -Answer-
1992
List 4 advantages of using nitrox -Answer-Extend bottom time
Shorten required surface interval
Safety margin
Less physically tired (fatigue)
Nitrox provides the greatest advantages for dives in what depth range? -Answer-15-
33 meter (50-100 foot) depth range
The "x" in EANx is often replaced with what? -Answer-Oxygen percentage
What compares the quantity of the component gas to a total of 100? What compares
it to 1? -Answer-Percentage.
Fraction.
Each of the individual components in a gas mixture will exert its chemical or physical
effects independently, according to what? -Answer-Its proportion in the mixture
Oxygen is what percentage of atmospheric air?
Nitrogen? -Answer-21%;
79%
The symptoms of nitrogen narcosis parallel those often seen in what? -Answer-
Alcohol intoxication
, If we heat a gas, we are adding _________, increasing the speed of the molecules
and the force of the impacts -Answer-Energy
Which law states: "At a constant temperature, the volume of a gas varies inversely
with absolute pressure, while the density of a gas varies inversely with absolute
pressure?" -Answer-Boyle's Law
Which law states: "The amount of any given gas that will dissolve in a liquid at a
given temperature is a function of the partial pressure of the gas that is in contact
with the liquid and the solubility coefficient of the gas in the particular liquid?" -
Answer-Henry's Law
What is the portion of the total gas pressure exerted by a single gas in a mixture of
gases? -Answer-Partial Pressure
Which law states: "The total pressure exerted by a mixture of gases is equal to the
sum of the pressures that would be exerted by each of the gases if it alone were
present and occupied volume."? -Answer-Dalton's Law
Each __________ that you descend in the ocean adds another atmosphere of
pressure to the one atmosphere of surface pressure. -Answer-10 meters (33 feet)
When you are at a depth of 20 meters of seawater (msw)/66 feet of seawater (fsw),
the absolute pressure is what? -Answer-3 ata
To convert depth to absolute pressure, you first find the water (hydrostatic) pressure
in atmospheres and then add what? -Answer-One atmosphere for the sea level air
pressure
To determine the partial pressure of a gas in a mixture, you multiply what two
numbers? -Answer-Gas fraction
Absolute pressure
Using the Oxygen Partial Pressure at Depth table, what is PO2 of EAN34 at a depth
of 24 msw (80fsw)? -Answer-1.16 ata
A stuporous condition characterized by impaired mental and physical performance
and changes in mood and behavior is known as _____. -Answer-Nitrogen narcosis
The mechanisms of nitrogen narcosis are thought to be similar to what? -Answer-
Gases used in anesthesia
What are the terms for absorption and elimination of nitrogen during a dive? -
Answer-Ingassing and offgassing
List the signs and symptoms of decompression sickness? -Answer-Excessive fatigue
weakness and tingling in limbs
limb and join pain and dysfunction
skin rashes and itching
