2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/85066Temperature is introduced as a derived concept from energy and entropy. We consider two sub-systems in equilibrium for several configurations. The equality of temperature of the sub-systems is obtained from the equilibrium condition. The isothermal transformation is defined for several configurations and from this definition we obtain the Clausius-Clapeyron equation. We apply the analysis to the ideal gas. The classical ideal gas appears as a limit and the problem of the measurement of temperature is analysed.16 pages, 2 figures (in portuguese language)General Physicstext