Pressure & Conversions Between Different Units of Pressure

Gas Pressure• Pressure is the result of the

collisions of the gas particles with the sides of its container

• --It is the force exerted over an area

• Existence of Air Pressure =

• Soda cans, Balloon in a bottle

Measuring Atmospheric Pressure

• The Barometer is used to measure air pressure

• Air pressure is measured by determining the height of a column of mercury which can be supported by air

Units of Pressure (Are Many)

• mmHg• in Hg • Atmospheres or atm• Lbs/in2

• Kilopascals or kPa• Torr

Pressure Conversion Factors• 1 atm =

• 760 mm Hg =• 29.9 in Hg =• 14.7 lbs/in2 =• 101.3 kPa =• 760 torr =• 1.01 bar =

• 1013 millibar

STP• When working with gases

standard conditions =• Temperature of 0oC• Pressure of :• 760 mmHg or • 1 atm or • 101.3 kPa