The Gas Laws
What Are The Gas Laws ?
The gas laws are a small number of simple statements about an ideal gas which can simplify the way in which we view that gas and calculate values for given properties of the gas.
The properties we are most interested in as far as gasses are concerned are
- Pressure
- Temperature
- Density
The Laws Themselves
The Gas Laws are derivations of a mathematical equation
pV = nRT
- p
- Pressure [N m-2]
- V
- Volume of the gas [m3]
- n
- Number of Moles of Gas
- R
- Gas Constant 8.231 J Mole-1 °K-1
- T
- Temperature [°K]
pV has dimensions of Nm.
nRT has dimensions of Nm.
Nm are the dimensions of energy.
Accordingly if any of these properties change, the energy of the gas changes.
An increase in the energy of one side will increase the energy of the other side.
The volume of a gas at constant pressure increase or decrease as Temperature increases or decreases.
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The product of pressure and volume for a gas is a constant. PV = C
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For a fixed number of moles of gas at constant volume, temperature is proportional to pressure.
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Under conditions of equal temperature and pressure, a volume of ANY gas has the same number of molecules in it as ANY other gas.
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A mole is mass in grams of a gas which is numerically equally to the mass of gas in AMUs.
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