Stumbling on Unit Conversion
Stumbling on Unit Conversion
(OP)
I want to check a coversion from ppm to ml/l.
Material O2 - Oxygen Density 1.429 kg/m3....1.429 mg/ml
Quantity 0.3 ppm O2 which is equal to 0.3 mg/kg
Math 0.3 mg/kg divided by 1.429 mg/ml = 0.2 ml/kg
Problem - reference I'm using shows the coversion to be 0.2 ml/l How is ml/kg converted to ml/l. If this was water i would just say 1l = 1kg but this is a gas.
Help...Thanks
Material O2 - Oxygen Density 1.429 kg/m3....1.429 mg/ml
Quantity 0.3 ppm O2 which is equal to 0.3 mg/kg
Math 0.3 mg/kg divided by 1.429 mg/ml = 0.2 ml/kg
Problem - reference I'm using shows the coversion to be 0.2 ml/l How is ml/kg converted to ml/l. If this was water i would just say 1l = 1kg but this is a gas.
Help...Thanks





RE: Stumbling on Unit Conversion
For non-liquid solutions ppm to mg/l is calculated using
mg/l = ppm * Mol Wght / 24.4
Then using density of gas divide mg/l by mg/ml answer is in ml/l units
so for oxygen 0.3 ppm * 32/24.4 = 0.393 mg/l
divide now by density 0.393 mg/l / 1.429 mg/ml = 0.275 ml/l
which is pretty close to 0.2 ml/l.
Sound correct?
RE: Stumbling on Unit Conversion
additionally, ppm in a liquid system is often expressed as weight/weight, while for air and gas it is often mol/mol (which is identical to volume/volume for most gases at low pressures, but can be substantially different to weight/weight).
RE: Stumbling on Unit Conversion
See thread127-48308: Conversion PPM(wt), PPM(vol), g/m3 (gas phase) and thread127-97413: conversion mg/Nm3 to PPM. Besides, what are T, P conditions and the nature of the dissolving gas ?
RE: Stumbling on Unit Conversion