How many mg is 380cc per hour?

Answer 1

The question, as stated, cannot be answered sensibly. A cubic centimetre per hour is a measure of volume per hour, with dimensions [L3T-1]. A microgram is a measure of mass, with dimensions [M]. The two measure different things and elementary dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information. Althernatively, a microgram per hour is a measure of mass per hour with dimensions [MT-1] but the rest of the argument remains unchanged.

As a simple mental exercise consider a cc of air and of water. They will have very different masses.