[avogado_and_toast]

When oxygen is used as a medical gas, it's remaining time until empty at a given flow rate sometimes needs to be calculated. In the equation used we have a list of "tank constants" for each O2 tank. They are made by dividing the tank's maximum volume by its maximum pressure.

I'm just wondering how that relates to Boyle's law where the constant is found by multiplying pressure by volume.

[Enthalpy]

From the units, of from the figures, you can decide whether the pressure multiplied or divided the volume in the given data.