Search results
Results From The WOW.Com Content Network
ISO TR 29922-2017 provides a definition for standard dry air which specifies an air molar mass of 28,965 46 ± 0,000 17 kg·kmol-1. [2] GPA 2145:2009 is published by the Gas Processors Association. It provides a molar mass for air of 28.9625 g/mol, and provides a composition for standard dry air as a footnote. [3]
The average molecular weight of dry air, which can be used to calculate densities or to convert between mole fraction and mass fraction, is about 28.946 [11] or 28.964 [12] [5] g/mol. This is decreased when the air is humid. The relative concentration of gases remains constant until about 10,000 m (33,000 ft). [13]
Oxygen is the most abundant chemical element by mass in the Earth's biosphere, air, sea and land. Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [ 68 ] About 0.9% of the Sun 's mass is oxygen. [ 19 ]
Another scale is mass fraction or, equivalently, percent by mass. [2] For example, the abundance of oxygen in pure water can be measured in two ways: the mass fraction is about 89%, because that is the fraction of water's mass which is oxygen. However, the mole fraction is about 33% because only 1 atom of 3 in water, H 2 O, is oxygen.
Fraction of inspired oxygen (F I O 2), correctly denoted with a capital I, [1] is the molar or volumetric fraction of oxygen in the inhaled gas. Medical patients experiencing difficulty breathing are provided with oxygen-enriched air, which means a higher-than-atmospheric F I O 2. Natural air includes 21% oxygen, which is equivalent to F I O 2 ...
is the molar mass of dry air, approximately 0.028 9652 in kg⋅mol −1. [note 1] is the Boltzmann constant, 1.380 649 × 10 −23 in J⋅K −1 [note 1] is the molecular mass of dry air, approximately 4.81 × 10 −26 in kg. [note 1]
Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...
The mass fraction can be calculated from the molar fraction by multiplying the molar fraction by the molecular mass for each constituent, to find a constituent mass, and comparing it to the summed masses of all the constituents. The actual mass of each constituent needed for a mixture is calculated by multiplying the mass fraction by the ...