Pressure

• force per unit area on a surface

• Pressure= force/area

• N/ m²

• atmospheric pressure- the "weight of all gases added together."

Units of pressure

• Millimeters of mercury=1 mm Hg= 1 torr. Average atmospheric pressure at sea level at 0 C is 760 mm Hg

• 1 atmosphere of pressure = 1 atm = 760 torr

• Pascal- pressure exerted by a force on one newton acting on an area of one square meter. 101325 Pa= 1 atm

STP

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• Standard Temperature and Pressure

  0 C or 273.15 K

  1 atm or 760 torr or 101325 Pa

  Standard molar Volume of a gas at STP is 22.4 L/mol

Daltons Law of partial pressures

• Partial Pressure- the pressure of an individual gas

• Daltons law- total pressure of a gas mixture is the sum of the partial pressures of the component gases. P1 + P2 + P3 + ....