Ratio of Vapour Pressure using Integrated Form of Clausius-Clapeyron Equation Calculator

Vapor Pressure Ratio Formula:

\[ \text{Pfiratio} = \exp\left(-\frac{LH \times \left(\frac{1}{T_f} - \frac{1}{T_i}\right)}{[R]}\right) \]

Ratio of Vapor Pressure:

Definition: This calculator determines the ratio of final to initial vapor pressure using the integrated form of the Clausius-Clapeyron equation.

Purpose: It's used in thermodynamics and physical chemistry to estimate how vapor pressure changes with temperature for a given substance.

The calculator uses the formula:

\[ \text{Pfiratio} = \exp\left(-\frac{LH \times \left(\frac{1}{T_f} - \frac{1}{T_i}\right)}{[R]}\right) \]

Where:

\( \text{Pfiratio} \) — Ratio of final to initial vapor pressure (dimensionless)
\( LH \) — Latent heat of vaporization (Joules)
\( T_i \) — Initial temperature (Kelvin)
\( T_f \) — Final temperature (Kelvin)
\( [R] \) — Universal gas constant (8.314 J/mol·K)

Explanation: The formula relates the change in vapor pressure to the temperature change through the substance's latent heat.

Details: Understanding vapor pressure changes is crucial for distillation processes, weather forecasting, and designing pressure systems.

Tips: Enter the latent heat in Joules, initial and final temperatures in Kelvin. All values must be positive.

Q1: What is latent heat of vaporization?
A: The energy required to change 1 mole of liquid to vapor at constant temperature and pressure.

Q2: Why must temperatures be in Kelvin?
A: The Kelvin scale is absolute and ensures correct calculations in thermodynamic equations.

Q3: What does a ratio > 1 indicate?
A: A ratio > 1 means vapor pressure increased (final T > initial T), while < 1 means it decreased.

Q4: How accurate is this calculation?
A: It assumes ideal behavior and constant latent heat, so it's most accurate for small temperature ranges.

Q5: Can I use this for any substance?
A: Yes, as long as you have the correct latent heat value for that substance at the given temperatures.