The discussion revolves around the conversion of mass flow rate to molar flow rate, specifically in the context of gases. Participants explore the methods and considerations involved in this conversion, including the role of density and standard conditions.
Participants express differing views on the necessity of using density for the conversion, with some asserting it is essential while others argue it is not. The discussion remains unresolved regarding the best approach to the conversion.
Participants mention the variability in standard conditions and gas densities used by different manufacturers, which may affect the accuracy of conversions. There is also a reference to the specific conditions under which the ideal molar volume is defined.
You should use the standard ideal molar volume to convert the flow rate from molar units to standard cubic centimeters per minute (sccm). The standard conditions are defined as P= 101325 Pa, T=273.15 K and Z=1.Dullard said:Mass flow may be described with a number of different units. I infer from your question that you may be starting with 'SLPM' or 'SCCM' - these are common mass flow meter units.
Chestermiller is correct, but getting from SLPM to the mass/time units does require the gas density. Specifically, it requires the 'standard' gas density assumed in the 'SLPM' units. In practice, everyone (who manufactures MFMs) uses their own version of 'standard' - mostly 0C vs 25C vs 70F reference temperature - it's an almost 10% error waiting to happen.