Chapter 5: Gas Laws

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1. The Ideal Gas Law
1. Variables:
 V= volume (liters, cubic decimeters, milliliters, cubic centimeters). n= amount in moles, n = (MM = molar mass from Periodic Table). T= temperature, for gases must be in Kelvin, K = oC = 273.15, usually find temperature to nearest degree, so only add 273. P= pressure (atmospheres, millimeters of mercury, kilopascals, torr. 1 atm = 760 mm Hg = 101.3 kPa = 760 torr = 29.92 in Hg = 14.7 lb/in2, these are all at 0 oC

torr named after Torricelli - Italian scientist, first person to accurately measure atmospheric pressure, 1640

Calculation of Gas Pressure

1. barometer - closed manometer, take h directly.
2. manometer - open manometer.
Pgas = Patm + P due to h mm Hg
H2O is on the atmospheric side in the h part of the equation, this will effectively give the addition or subtraction from atmospheric pressure.

Relation between variables;

## PV=nRT

where R is a true constant, it is the same for all gases and is independent of P, V, n or T.

inputting standard temperature and pressure (STP) for any gas will give the same R, Avogadro's Law - the same number of particles at the same P, T, and V.