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A large scuba tank (Figure 8.16) with a volume of 18 L is rated for a pressure of 220 bar. The tank is filled at 20 °C and contains enough air to supply 1860 L of air to a diver at a pressure of 2.37 atm (a depth of 45 feet). Was the tank filled to capacity at 20 °C?

a) Yes
b) No

User Triss
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1 Answer

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Final answer:

To assess if the scuba tank was filled to its 220 bar capacity at 20°C, the ideal gas law must be used to compare the moles of air at the tank's rated pressure and the supplied air at a diver's pressure of 2.37 atm. Calculations will show if the air provided is less than the tank's capacity, indicating it was not filled to the maximum.

Step-by-step explanation:

To determine if the scuba tank was filled to capacity at 20 °C, we can use the ideal gas law (PV=nRT) and compare the total amount of air supplied to the diver at a pressure of 2.37 atm (equivalent to 45 feet depth) against the tank's capacity at a pressure of 220 bar (or 220 times atmospheric pressure).

Assessment

  1. Convert the tank's rated pressure from bar to atm (1 bar = 0.98692 atm) to maintain consistency with the diver's pressure units.
  2. Convert the liter measurements into volumes relative to standard conditions (STP: 1 atm, 0 °C).
  3. Use the ideal gas law to calculate the number of moles (n) of air contained in the scuba tank at its rated pressure and temperature.
  4. Use the ideal gas law again to calculate the number of moles of air corresponding to the volume of 1860 L of air at 2.37 atm and 20 °C (the diver's conditions).
  5. Compare the two results to assess if the tank was filled to its capacity.

Placeholder Values:

  • 1 bar = 0.98692 atm
  • 220 bar = 220 x 0.98692 atm
  • R (ideal gas constant) = 0.0821 L·atm/mol·K
  • Temperature in Kelvin = 20 °C + 273.15

Upon calculation, if the moles of air calculated at the diver's condition (2.37 atm, 20 °C) are less than the moles of air the tank can hold at its rated condition (220 bar, 20°C), the scuba tank was not filled to capacity.

User SleepyMurph
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