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1.7. Consequences from the Main Equation of Molecular-Kinetic
Theory of Ideal Gas. Ideal Gas Laws.

The before established experimental gas laws follow from the main

equation of molecular-kinetic theory of ideal gas.

1. isothermal process

If T=const there are three constant values kn ,, T in equation (1.6.3).
Therefore
p V  const or Vp 1 1  p 2 V (1.7.1)
2

Thus, we received Boyle's law. Boyle's law shows that the product of an

ideal gas pressure is always constant at
constant temperature.

An isothermal process is a change of a
system, in which the temperature remains

constant. This typically occurs when a
system is in contact with an outside thermal
reservoir (heat bath), and the change occurs

slowly enough to allow the system to
continually adjust to the temperature of the

Figure 7.1 reservoir through heat exchange. For
example, the piston in cylinder moves
slowly up due to slow diminishing of loading on the piston (as shown in
figure 7.1)

Isotherm – in thermodynamics, is a curve on a p-V (fig 7.2) or p-T
(fig. 7.3)diagram for an isothermal process

Figure 7.2 Figure 7.3

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