Ideal gas except for the specification of these constants. The results of the quantum Boltzmann gas are used in a number of cases including the Sackur–Tetrode equation for the entropy of an ideal gas and the Saha ionization equation for a weakly ionized plasma. The classical thermodynamic properties of an ideal gas can be described by two equations of state: The ideal gas law is the equation of state for an ideal gas, given by: where The ideal gas law is an extension of experimentally discovered gas laws. It can also be derived from microscopic considerations. Real fluids at low density and
Negative number general, subtraction of a positive number yields the same result as the addition of a negative number of equal magnitude. Thus and On the other hand, subtracting a negative number yields the same result as the addition a positive number of equal magnitude. (The idea is that "losing" a debt is the same thing as "gaining" a credit.) Thus and When multiplying numbers, the magnitude of the product is always just the product of the two magnitudes. The sign of the product is determined by the following rules: Thus and The reason behind the first example is simple: adding three