Seeking help with a question regarding units
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In some sources, I’ve seen that the oxygen content is expressed in %mol. What does this mean? Also, is there any conversion factor between %mol and ppm wt (ppm vol)? Those who know it, please share. Thank you first
It’s the mole fraction, right? Irregular way of expression. The definitions and ways of expressing the mass fraction, concentration, mass concentration, etc., of chemical substances are as follows: The mass ratio between chemical substances A and B should be expressed as: m(A)∶m(B)=2∶1 [A∶B=2∶1 is incorrect] ； The volume ratio between the chemical substances should be expressed as: V (A)∶V(B)=2∶1 ； The ratio of amounts (or molar ratio, particle count ratio) between chemical substances should be expressed as: n(A)∶n(B)=2∶1 ； A and B in parentheses should be the names or molecular formulas of the chemical substances. The mass fraction of chemical substance A should be expressed as: w(A) = 20% [A = 20% is incorrect] ； The volume fraction of the chemical substance should be expressed as: φ (A)=20% ； The molar fraction of the chemical substance should be expressed as: x (A)=20%. It should be emphasized that only the molar concentration can be referred to simply as concentration; its unit is mol/L. This can be expressed as: c(A) = 3 mol/L, or c_A = 3 mol/L. The mass concentration can be expressed as: ρ (A)=3g/L, but the mass concentration should not be abbreviated as “concentration”. It is incorrect to refer to the mass fraction, volume fraction, or molar fraction of a substance as “concentration”. The symbols m, V, n, w, φ, x, c, ρ must be used in conjunction with the molecular formula or name of a chemical substance; they cannot be used on their own. For example, expressions such as w=20%, A∶B=2∶1, or using “%” to indicate concentration are all incorrect.
%mol is molar percentage; ppm wt is parts per million (by weight); ppm vol is parts per million (by volume)