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The global mean pressure at the surface of the Earth is PS = 984 hPa, slightly less than the mean sea-level pressure because of the elevation of land. We deduce the total mass of the atmosphere ma: (2.2) where R = 6400 km is the radius of the Earth. The total number of moles of air in the atmosphere is Na = ma/Ma = 1.8x10 20 moles. Exercise 2-1.
4 kwi 2020 · In this equation, p(h) is the atmospheric pressure at altitude h, p 0 is the atmospheric pressure at sea level, g is the gravitational acceleration, ρ 0 is the mass density of air at sea level, R is the gas constant, T is the temperature, M is the (average) molar mass, m is the average mass of a gas molecule, and H is a composite parameter ...
4 kwi 2020 · The atmospheric pressure (p) can be simply related to the temperature (T) by the barometric formula [16], in the first approximation of treating air as an ideal gas (R is molar gas constant,...
The air density at sea level does not vary much around the world; the sea-level pressure varies by at most 5%, and the temperature rarely departs by more than 15% from 273 K, so that na remains within 25% of the value calculated here. The number density of CO2 is derived from the mixing ratio CCO2 = 365 ppmv: M a = C N2M N2 ++C O2M O2 C ArM Ar
Hydrostatic air pressure at any altitude z (m) above sea level is found by inte- grating the product of air density and gravity from the top of the atmosphere to altitude z with
Learning Objectives. to describe and measure the pressure of a gas. At the macroscopic level, a complete physical description of a sample of a gas requires four quantities: temperature (expressed in kelvins), volume (expressed in liters), amount (expressed in moles), and. pressure (in atmospheres).
Surface Pressure vs. Sea Level Pressure • Sea Level Pressure – the pressure that would exist if the observation point were at sea level. • Surface Pressure – the pressure observed at a particular location ATMO 1300 Equation of State • Ideal gas law – P = pressure (Pa) – ρ= density (kg/m3) – T = temperature (K)
