Question

How do you convert $255mmHg$ to $atm$ ? What about $620torr$ to PSI?

Answer 1

A barometer tests the pressure of the gas at the height of the column. A millimeter of mercury (mmHg) is one unit of gas pressure. In honour of the inventor of the barometer, Evangelista Torricelli, the equivalent unit of mmHg is called torr. The normal unit of pressure is the Pascal(Pa).blaise pascal was a mathematician and physicist.

Complete step-by-step solution:
Pressure is the amount of force applied normally to the surface area of an object.it is also stated as the force applied per unit area which is perpendicular to the surface. Pressure is designed with the letter P and can also be used on some occasions.
PSI (pound per square inch) is the unit of pressure or stress based on avoirdupois units. A pound per square inch which clears that pressure is relative to a vacuum rather than the ambient atmospheric pressure.
In the SI unit system there are seven SI base units and three supplementary units.
The conversion factor from $mmHg$ (or $torr$ ) to $atm$ :
$1atm=760mmHg=760torr$
Conversion factor for PSI is:
I$51.7149torr=1PSI$
Conversion of units
$1atm=760mmHg$
Dividing the above equation by $1atm$ then we get the actual ratio for the conversion.
$\dfrac{1 atm}{1 atm}=1=\dfrac{760 mmHg}{1 atm}=\dfrac{1 atm}{760 mmHg}$
Thus we get
${{P}_{atm}}=255mmHg\times \dfrac{1atm}{760mmHg}$
We have a ratio that is equal to 1:
$\begin{aligned} & {{P}_{torr}}=620torr\times \dfrac{1PSI}{51.7149torr} \\\ & {{p}_{torr}}=12.0PSI \\\ \end{aligned}$
Conversion of $255mmHg$ to $atm$ is done and $620torr$ to PSI is also converted.

Note: The atmosphere ($atm$ ) is another unit of pressure widely used.1atm of pressure is considered the normal ambient pressure which is equivalent to $760mmHg$ which is$101.3kPa$. Pounds square inch(psi)is often also specified at atmosphere pressure. Blaise Pascal was also an early pioneer of “The game theory”.