# What units are used to measure gas pressure?

May 20, 2018

A torr.

#### Explanation:

760 Torr equal one atm, or atmospheric pressure. And the piece of equipment used to measure torrs is manometer.

( Sorry this is short if you need further understanding await the answer of someone else. )

May 20, 2018

Perhaps we should finally address this question....

#### Explanation:

Gas pressure may be quoted with units of $\text{foot-pounds}$, $\text{mm Hg}$, $\text{Pascals}$...all of these report $\text{force per unit area}$. For chemists, probably the most intuitive unit is the $\text{atmosphere}$.

And $\text{1 atmosphere"-=760*mm*Hg-=101.3*kPa-=32*"psi}$...

As a refinement....engineers often speak of gauge pressure versus absolute pressure. When we fill a tyre on a car, and we use the manual in the car to give us the appropriate pressure, the $\text{gauge pressure}$ is specified, the which is the pressure OVER atmospheric....i.e.

$\text{gauge pressure"-="internal pressure "-" atmospheric pressure}$

A tyre at atmospheric pressure would thus have $\text{ZERO gauge pressure}$. Sometimes (especially in the States) we see $\text{psig}$, i.e. $\text{pounds per square inch gauge}$.

Thus $\text{ZERO gauge pressure} = 1 \cdot a t m .$