KentChemistry HOME

 
 

 
Custom Search

More Gas Law links

 

Pressure of Gases

 
Pressure is defined a Force per unit area. With gases the force comes from the gas molecules hitting the side of the container. Air pressure is measured with a barometer.

pressure = force / area

P = F / A

Gas pressure is a gauge of the number and force of collisions between gas particles and the walls of the container that holds them. The SI unit for pressure is the pascal (Pa), but other pressure terms include atmospheres (atms), millimeters of mercury (mmHg), and torr. The following is a list of all of the standard pressure in every unit for pressure. 

1 Atm = 760 torr =760 mmHg = 101.325kPa = 101,325 Pa = 14.7lb/in2  = 29.92 inHg

 

"Atmospheric Pressure" is defined as the force per unit area exerted against a surface by the weight of the air above that surface. The Diagram below , the pressure at point "X" increases as the weight of the air above it increases. The same can be said about decreasing pressure.

In the mountains there is less air above you so less pressure. Since gases are compressible, this creates an environment in the mountains that has less air per unit volume. It will be harder to breathe in the mountains because there is actually less O2 per volume compared to at sea level.

 

 

 

Pressure Conversion Examples-Highlight to reveal answers

 

Set up

Answers
99.6 kPa  to atm 99.6 kPa X

1 atm

101.3 kPa

= 0.983 atm
       
0.983 atm to mmHg 0.983 atm X

760 mmHg

1 atm

= 747 mm Hg
       
747 mm Hg to torr

747 mm Hg X

760 torr

760 mmHg

=747 torr
       
747 torr to kPa

747 torrX

101.3 kPa

760 torr

= 99.6 kPa
       
50.0 kPa  to atm 50.0 kPa X

1 atm

101.3 kPa

= 0.494 atm
       
2.60 atm to mmHg 2.60 atm X

760 mmHg

1 atm

= 1976 mm Hg
       
315 torr to mmHg

315 mm Hg X

760 mmHg

760 torr

=315 mmHg
       
5.0 atm  to kPa 5.0 atm X

101.3 kPa

1 atm

= 505 kPa
       
260 mmHg to atm  260 mmHg X

1 atm

760mmHg

= 0.342 atm
       
21.2 kPa to torr

21.2 kPaX

760 torr

101.3 kPa

= 159 torr
 

 

Chemical Demonstration Videos