NITROX EXAM QUESTIONS AND
ANSWERS
Using Boyles law we can easily know that if you compared two 11 liter (80 cubic foot)
scuba cylinders with different pressures to the one with double the pressure also has
a greater volume of gas (T/F) -Answer-True
Henry's Law -Answer-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."
Henry's Law addresses the quantity of a gas that will dissolve, and describes the rate
at which the gas will dissolve (T/F) -Answer-False, it does not describe the rate at
which gas disolves
Dalton Law States -Answer-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 the volume.
According to Daltons law, the pressure exerted by each gas mixture will add up to
the total pressure of gas (T/F) -Answer-True
Converting between depth and pressure by formula (Metric) -Answer-P barabsolute
= (D msw / 10 msw/bar ) + 1 bar = [(D msw + 10 msw) / 10msw/bar]
P= absolute pressure (ATA)D= Depth in meters
Converting absolute pressure to depth is the reverse:
D msw = (P barabsolute - 1 bar) x 10 msw/bar
Converting between depth and pressure by formula (Imperial) -Answer-P ata = (D
fsw / 33 fsw/atm) + 1 atm = {(D fsw + 33 fsw) / 33 fsw/atm}
P= absolute pressure (ATA)D= Depth in feet
Converting absolute pressure to depth is the reverse:
D fsw = (P ata - 1 atm) x 33 fsw/atm
Partial Pressure formula (If you know the partial pressure and the total pressure) -
Answer-Fg = Pg/Ptotal
Partial Pressure formula (If you know the partial pressure and fraction/percentage of
the gas) -Answer-Ptotal = Pg/Fg
Using diving terms, partial pressure is calculated as: partial pressure = (total
absolute pressure) × (volume fraction of gas component) For the component gas "i":
pi = P × F. -Answer-
If a gas is heated in a rigid closed container the pressure will _____________ -
Answer-Increase
, Pair the gas law with its name -Answer-"At a constant temperature, the volume of a
gas varies inversely with the absolute pressure, while the density of a gas varies
directly with absolute pressure:" Boyle's Law
"If one quantity of gas will dissolve at one atmosphere of pressure, then three
quantities of gas will dissolve at three atmospheres:" Henry's Law
What is the absolute pressure at 17 msw (56 fsw) -Answer-2.7 ata
The _________________ of a specific gas in a mix is the portion of the total
pressure exerted by that gas -Answer-Partial Pressure
The Oxygen Partial Pressure (PO2) in EAN35 at a depth of 26 msw (85 fsw) is -
Answer-1.3 ata
The absolute pressure at 17 msw (56 fsw) is -Answer-2.7 ata
What is the partial pressure of oxygen in the air at a depth of 21 msw (69 fsw) -
Answer-.65
If the oxygen partial pressure in your mix is 1.3 ata at a depth of 37 msw (122 fsw),
what is the fraction of oxygen in the mix -Answer-.28
At one atmosphere absolute there is 79% nitrogen or a partial pressure of 0.79
nitrogen as a diver descends the percentage of gas doesnt change but the partial
pressure of the gas will increase with increased pressure (T/F) -Answer-True
The Signs and Symptoms of DCS Do Not Vary and Can Be Easily Identified No
Matter The Injury or Severity of The Case (T/F) -Answer-False
Central nervous system toxicity -Answer-CNS toxicity can result from relatively short
exposures to high partial pressures of oxygen.
The other type is called pulmonary toxicity or whole body toxicity -Answer-Pulmonary
toxicity results from prolonged exposure to elevated partial pressures of oxygen
(above about 0.5 atmosphere). As the name implies, its most pronounced effects are
on the lungs, producing signs and symptoms such as chest tightness, breathing
discomfort and pain, shortness of breath, and coughing. Development of pulmonary
toxicity requires long-term exposures such as encountered in saturation diving,
certain military and commercial diving, or recompression chamber treatment.
Pulmonary toxicity is not a concern of the recreational nitrox diver; CNS toxicity is a
concern. -Answer-
Using the NOAA Oxygen Exposure limits the 24 hour limit at the maximum
recreational partial pressure of oxygen (PPO2) is 200 minutes (T/F) -Answer-False
Match each statement True or False: -Answer-The mechanisms of nitrogen narcosis
are thought to be similar to Anethesia: True
ANSWERS
Using Boyles law we can easily know that if you compared two 11 liter (80 cubic foot)
scuba cylinders with different pressures to the one with double the pressure also has
a greater volume of gas (T/F) -Answer-True
Henry's Law -Answer-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."
Henry's Law addresses the quantity of a gas that will dissolve, and describes the rate
at which the gas will dissolve (T/F) -Answer-False, it does not describe the rate at
which gas disolves
Dalton Law States -Answer-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 the volume.
According to Daltons law, the pressure exerted by each gas mixture will add up to
the total pressure of gas (T/F) -Answer-True
Converting between depth and pressure by formula (Metric) -Answer-P barabsolute
= (D msw / 10 msw/bar ) + 1 bar = [(D msw + 10 msw) / 10msw/bar]
P= absolute pressure (ATA)D= Depth in meters
Converting absolute pressure to depth is the reverse:
D msw = (P barabsolute - 1 bar) x 10 msw/bar
Converting between depth and pressure by formula (Imperial) -Answer-P ata = (D
fsw / 33 fsw/atm) + 1 atm = {(D fsw + 33 fsw) / 33 fsw/atm}
P= absolute pressure (ATA)D= Depth in feet
Converting absolute pressure to depth is the reverse:
D fsw = (P ata - 1 atm) x 33 fsw/atm
Partial Pressure formula (If you know the partial pressure and the total pressure) -
Answer-Fg = Pg/Ptotal
Partial Pressure formula (If you know the partial pressure and fraction/percentage of
the gas) -Answer-Ptotal = Pg/Fg
Using diving terms, partial pressure is calculated as: partial pressure = (total
absolute pressure) × (volume fraction of gas component) For the component gas "i":
pi = P × F. -Answer-
If a gas is heated in a rigid closed container the pressure will _____________ -
Answer-Increase
, Pair the gas law with its name -Answer-"At a constant temperature, the volume of a
gas varies inversely with the absolute pressure, while the density of a gas varies
directly with absolute pressure:" Boyle's Law
"If one quantity of gas will dissolve at one atmosphere of pressure, then three
quantities of gas will dissolve at three atmospheres:" Henry's Law
What is the absolute pressure at 17 msw (56 fsw) -Answer-2.7 ata
The _________________ of a specific gas in a mix is the portion of the total
pressure exerted by that gas -Answer-Partial Pressure
The Oxygen Partial Pressure (PO2) in EAN35 at a depth of 26 msw (85 fsw) is -
Answer-1.3 ata
The absolute pressure at 17 msw (56 fsw) is -Answer-2.7 ata
What is the partial pressure of oxygen in the air at a depth of 21 msw (69 fsw) -
Answer-.65
If the oxygen partial pressure in your mix is 1.3 ata at a depth of 37 msw (122 fsw),
what is the fraction of oxygen in the mix -Answer-.28
At one atmosphere absolute there is 79% nitrogen or a partial pressure of 0.79
nitrogen as a diver descends the percentage of gas doesnt change but the partial
pressure of the gas will increase with increased pressure (T/F) -Answer-True
The Signs and Symptoms of DCS Do Not Vary and Can Be Easily Identified No
Matter The Injury or Severity of The Case (T/F) -Answer-False
Central nervous system toxicity -Answer-CNS toxicity can result from relatively short
exposures to high partial pressures of oxygen.
The other type is called pulmonary toxicity or whole body toxicity -Answer-Pulmonary
toxicity results from prolonged exposure to elevated partial pressures of oxygen
(above about 0.5 atmosphere). As the name implies, its most pronounced effects are
on the lungs, producing signs and symptoms such as chest tightness, breathing
discomfort and pain, shortness of breath, and coughing. Development of pulmonary
toxicity requires long-term exposures such as encountered in saturation diving,
certain military and commercial diving, or recompression chamber treatment.
Pulmonary toxicity is not a concern of the recreational nitrox diver; CNS toxicity is a
concern. -Answer-
Using the NOAA Oxygen Exposure limits the 24 hour limit at the maximum
recreational partial pressure of oxygen (PPO2) is 200 minutes (T/F) -Answer-False
Match each statement True or False: -Answer-The mechanisms of nitrogen narcosis
are thought to be similar to Anethesia: True
