Vapor Pressure Calculator (Solvent/Solution)

Historical Background

The concept of vapor pressure was established through experiments on the behavior of liquids and their vapors in the 19th century. Raoult’s Law, formulated by French chemist François-Marie Raoult in 1887, describes how the vapor pressure of an ideal solution is proportional to the mole fraction of the solvent. This principle has been fundamental in understanding solutions' thermodynamic properties.

Calculation Formula

The vapor pressure of a solution is given by Raoult's Law:

\[ VP{\text{solution}} = MF \times VP{\text{solvent}} \]

Where:

• \( VP_{\text{solution}} \) is the vapor pressure of the solution,
• \( MF \) is the mole fraction of the solvent,
• \( VP_{\text{solvent}} \) is the vapor pressure of the pure solvent.

Example Calculation

For example, if the mole fraction of the solvent is 0.75 and the vapor pressure of the solvent is 2000 Pa, the vapor pressure of the solution can be calculated as:

\[ VP_{\text{solution}} = 0.75 \times 2000 = 1500 \text{ Pa} \]

Importance and Usage Scenarios

• Chemical Engineering: Predicting vapor pressure is essential in distillation, evaporation, and other industrial processes.
• Pharmaceuticals: Understanding the vapor pressure of solutions helps in drug formulation and stability testing.
• Environmental Science: Vapor pressure is key in assessing the volatility of pollutants and their atmospheric behavior.

Common FAQs

1. What is vapor pressure?

   • Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase at a given temperature.

2. How does the mole fraction affect vapor pressure?

   • According to Raoult’s Law, the vapor pressure of the solution decreases as the mole fraction of the solvent decreases, reflecting the diluted presence of the solvent.

3. Can this formula be applied to all solutions?

   • Raoult’s Law applies most accurately to ideal solutions. Non-ideal solutions may deviate due to intermolecular forces.

This calculator helps determine the vapor pressure of solutions based on solvent properties, making it useful in both academic and industrial applications.