# How do you convert atm to torr?

Mar 11, 2017

divide by 760

#### Explanation:

$1$ torr = $\frac{1}{760} a t m$

to convert atm to torr, divide by $760$.

e.g. $319 , 200$ torr = $420$ atm.

Mar 11, 2017

$1 \cdot \text{atmosphere}$ will support a column of mercury $760 \cdot m m$ high.........

#### Explanation:

And thus to measure pressure we often use a mercury manometer, and the length of a mercury column is a highly visual measure of the strength of the vacuum, and, if you isolate your manometer from the pump, you can check to see whether you have any leaks in your gas line.

It may seem a bit whack to use a unit of length to measure pressure, but this is what is commonly done:

$1 \cdot a t m$ $\equiv$ $760 \cdot m m \cdot H g$ $=$ $760 \cdot \text{Torr}$.

(i.e. $1 \cdot m m \cdot H g = 1 \cdot \text{Torr}$.) $\text{Torr}$, so I am told, are named after Evangelista Torricelli (beautiful name!), an Italian physical scientist of the 17th century, who developed the mercury barometer.

And thus a measurement of $5 \cdot m m \cdot H g$ represents (5*mm)/(760*mm*Hg*atm^-1)=??atm.

You do not measure pressures GREATER than $1 \cdot a t m$ in $m m \cdot H g$. Try it and you will (probably) get droplets of mercury all the benchtop, and the floor, where the metal will inhabit every crack and every cranny. This is a major cleanup job, which contract cleaners would not touch.