There are too many conversions in the life of a chemical engineer to remember arbitrarily which require dividing and which require multiplying. If you just know and understand the first principles it all becomes obvious.
The pressure at the base of a column of liquid is related to the height of the column by the relationship (in any consistent set of units):
Pressure = fluid density x acceleration of gravity x column height
In my memory banks this is stored as "P equals rho G H". This is much easier to remember than whether you need to multiply or divide. And far more useful.
For example, to convert from 5 bar to mm of a liquid with a density of 850 kg/m
3 follow the following logic (assuming we are working in SI Units).
5 bar is equal to 500 000 Pascal. Acceleration of gravity is 9.81 m/s
2. Column height is therefore
H = P / (rho x G) = 500 000 / (850 x 9.81) = 59.96 metre or 59 960 mm.
Katmar Software - AioFlo Pipe Hydraulics
"An undefined problem has an infinite number of solutions"