To convert mass flow rate to molar flow rate, divide the mass flow rate by the molecular weight of the gas. Common units for mass flow include Standard Liters Per Minute (SLPM) and Standard Cubic Centimeters per Minute (SCCM). The conversion requires knowledge of the gas density, which varies based on the reference temperature used by manufacturers, leading to potential errors of nearly 10%. For accurate conversions, utilize the standard ideal molar volume under defined conditions: P=101325 Pa, T=273.15 K, and Z=1.
PREREQUISITESEngineers, chemists, and technicians involved in gas flow measurements, particularly those working with mass flow meters and conversions in laboratory or industrial settings.
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.