Density of air

If the mass of a substance in air is its density the density of weights used in making the weighing p, and the density of air p, the true mass of the substance in vacuo, is... 

After adding p-rosaniline and formaldehyde, the colored solution was diluted to 25 ml in a volumetric flask. The absorbance was measured at 569 nm in a 1-cm cell, yielding a value of 0.485. A standard sample was prepared by substituting a 1.00-mL sample of a standard solution containing the equivalent of 15.00 ppm SO2 for the air sample. The absorbance of the standard was found to be 0.181. Report the concentration of SO2 in the air in parts per million. The density of air maybe taken as 1.18 g/L. 

When the density of air or gas varies, horsepower and pressure vary directly as the density, speed and capacity being constant. 

The density of air saturated with a ehemieal vapour may not differ signifieantly from that of air itself. Refer to Table 4.2. This is an important eonsideration when designing ventilation systems, i.e. both high- and low-level extraet vents may be desirable. 

Table 4.2 Relative densities of air saturated with selected chemicals at 25°C...

These coefficients must be multiplied by the density of air and tissue, respectively. Figure 15.7.2-1 depicts a radiation fallout field. Let C be the curie activity/m. The radiation into a unit area receptor at z = 1 m above the ground. The area is emitting C r dr d0 gammas/s. These are attenuated in the air as exp(-p, R) and geometrically as l/(4 7t R). The radiation received by the receptor is given by equation 15.7.2-1 which becomes 15.7.2-2 by a change of... 

The effect of buoyancy in gases released into the air can be related either to the difference in the molecular weights or to the difference in temperature. Jb characterize the buoyancy for gases with a molecular density significantly different from the density of air, Elterman proposed a parameter P, with units... 

In ventilation applications, where the density of the manometer fluid is much higher than the density of air, the pressure difference Ap can be expressed using the equation... 

H = visible flame height S = 2.3 X = flame speed = wind speed d = cloud depth g = gravitational acceleration po = fuel-air mixture density pj = density of air r = stoichiometric air-fuel mass ratio a = expansion ratio for stoichiometric combustion under constant pressure (typically 8 for hydrocarbons)... 

Calculate the square of the ratio of fuel density and the density of air from molecular weights ... 

Calculate the air-fuel mass ratio r from the stoichiometric mixture composition < >j, and the densities of air and fuel ... 

Po = density of air under actual operating conditions, lb/fF Pj = density of air under standard conditions, lb/ft ... 

Helium-filled balloons rise in the air because the density of helium is less than the density of air. 

The air is said to be thinner in higher altitudes than at sea level. Compare the density of air at sea level where the barometric pressure is 755 mm Hg and the temperature is 0°C with the density of air on top of Mt. Everest at the same temperature. The barometric pressure at that altitude is 210 mm Hg (3 significant figures). Take the molar mass of air to be 29.0 g/mol. 

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