What is the Clausius-Clapeyron equation and what is it used for?

The Clausius-Clapeyron equation relates vapor pressure to temperature: d(ln P_sat)/dT = delta_H_vap/(R*T^2), or integrated form: ln(P2/P1) = (delta_H_vap/R)*(1/T1 - 1/T2). It shows that vapor pressure increases exponentially with temperature. Uses: estimate vapor pressure at different temperatures from one data point and heat of vaporization, construct vapor pressure curves, and understand boiling point elevation and depression. Assumes constant heat of vaporization and ideal gas vapor - Antoine equation is more accurate for precise calculations.