Let us assume Nitrogen as an ideal gas. From Table 1.8 (textbook

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Let us assume Nitrogen as an ideal gas. From Table 1.8 (textbook),
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RNitrogen  296.8 J/(kg  K)
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Note) local standard atmosphere depends on altitude:
 Prescott (5,000 ft): 12.228 psi
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 Daytona Beach (sea-level): 14.696 psi
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Applying the equation of state (ideal gas law):
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p   RT  1.5 kg/m3   296.8 J/(kg  K)   25 oC  273 K   = 132,670 Pa (132.67 kPa)
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Note: this is the “absolute” pressure. The purpose of this problem is to determine
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the “gage” pressure.
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The gage pressure is the pressure above (or below, if vacuum) the atmospheric
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pressure, where the given atmospheric pressure here is: patm  97 kPa
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Therefore:
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pgage  pabs  patm  132.67 kPa  97 kPa = 35.67 kPa
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Note that the atmospheric pressure is equal to “ZERO GAGE” pressure:
patm  0 (gage)
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