Pressure vs Temperature

Gay-Lussac's law: at constant volume, pressure × T = constant. P/T = const.

Equivalently: P₁/T₁ = P₂/T₂ for an ideal gas at constant V.

Direct proportionality between P and absolute T.

On P-T graph: straight line through origin (in Kelvin).

Extrapolating P to zero gives T = 0 K = absolute zero.

Microscopic: higher T ⇒ faster molecules ⇒ stronger wall collisions ⇒ higher P.

Pressure cookers use this: heating sealed container raises P, which raises boiling point ⇒ faster cooking.

Special case of ideal gas law at constant V and n.