Gas Laws

Four measurable quantities describe the state of any confined gas sample -- its pressure ($P$), volume ($V$), absolute temperature ($T$) and amount in moles ($n$) -- and the experimentally observed relationships between pairs of these quantities, holding the other two constant, are summarised by five gas laws: Boyle's law (relating $P$ and $V$), Charles's law (relating $V$ and $T$), Gay-Lussac's law (relating $P$ and $T$), Avogadro's law (relating $V$ and $n$) and Dalton's law of partial pressures (for mixtures of gases). Each of these laws was established from careful experimental measurement long before any theoretical explanation for gas behaviour existed, and together they went on to play a foundational role in the historical development of chemistry -- for instance in confirming atomic and molecular theories of matter. The section …