The formula to calculate the vapor pressure using the Clausius-Clapeyron equation is:
\[ \ln\left(\frac{P2}{P1}\right) = \frac{\Delta H_{vap}}{R} \left( \frac{1}{T1} - \frac{1}{T2} \right) \]
Where:
The Clausius-Clapeyron equation is a mathematical relationship that describes the phase transition between two states of matter, such as the transition from liquid to gas during evaporation. It was developed by physicists Rudolf Clausius and Benoît Paul Émile Clapeyron in the 19th century. The equation provides a quantitative way of understanding how the pressure at which this phase transition occurs depends on the temperature. It is derived from the principles of thermodynamics and assumes that the transition between phases is an equilibrium process.
Let's assume the following values:
Using the formula to calculate the natural logarithm of the ratio of the vapor pressures:
\[ \ln\left(\frac{1500}{1000}\right) = \frac{40000}{8.314} \left( \frac{1}{300} - \frac{1}{350} \right) \]
The result is approximately 2.25.
