(a) Boyle's Law
English scientist Robert Boyle investigated the relationship between the volume of a dry ideal gas and its pressure. It states that at constant temperature, the pressure is inversely proportional to the volume of a definite amount of gas. Mathematically,
(b) Charle's Law
French scientist Jacques Charles experimented with gas under constant pressure and his observations have been formalized into Charle's law.
The volume of a gas at constant pressure is directly proportional to the absolute temperature. Mathematically, it can be expressed as:
(c) Gay-Lussac's Law
French scientist Joseph Gay-Lussac investigated the relationship between the pressure of a gas and its temperature. It states that the pressure of a gas at constant volume is directly proportional to the absolute temperature. The mathematical statement is as follows:
(d) Combined Gas Laws
Any two of the three gas laws of Boyle, Charles, or Gay-Lussac can be combined, hence the name, combined gas law. In short, this combined gas law is used when it is difficult to keep either the temperature or pressure constant:
This relationship can be used to predict pressure, volume, and temperature relationships where any five of the six variables are known.