How To Calculate Partial Pressure From Vapor Pressure

Partial Pressure Formula:

\[ P_i = e \times \frac{n_i}{n_{vapor}} \]

Partial Pressure (P_i):

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1. What Is Partial Pressure?

Partial pressure is the pressure that a single gas component in a mixture of gases would exert if it alone occupied the entire volume. It's a fundamental concept in gas laws and thermodynamics, particularly useful in understanding gas mixtures and vapor-liquid equilibrium.

2. How Does The Calculator Work?

The calculator uses the partial pressure formula:

\[ P_i = e \times \frac{n_i}{n_{vapor}} \]

Where:

\( P_i \) — Partial pressure of component i (Pa)
\( e \) — Total vapor pressure of the mixture (Pa)
\( n_i \) — Moles of component i in the vapor phase (mol)
\( n_{vapor} \) — Total moles in the vapor phase (mol)

Explanation: This formula calculates the partial pressure of a specific component in a gas mixture based on its mole fraction and the total vapor pressure.

3. Importance Of Partial Pressure Calculation

Details: Partial pressure calculations are essential in various fields including chemical engineering, atmospheric science, respiratory physiology, and industrial processes involving gas mixtures. They help predict gas behavior, solubility, and reaction rates.

4. Using The Calculator

Tips: Enter the total vapor pressure in Pascals (Pa), moles of the specific component, and total moles in the vapor phase. All values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between partial pressure and mole fraction?
A: Partial pressure is directly proportional to mole fraction. For an ideal gas mixture, the partial pressure of a component equals its mole fraction multiplied by the total pressure.

Q2: Can this formula be used for real gases?
A: This formula assumes ideal gas behavior. For real gases, especially at high pressures or low temperatures, corrections may be needed using equations of state.

Q3: How does temperature affect partial pressure?
A: Temperature affects the total vapor pressure (e) in the formula. As temperature increases, vapor pressure typically increases, which affects all partial pressures in the mixture.

Q4: What units should I use for this calculation?
A: While Pascals are used here, you can use any pressure units as long as you're consistent. Common alternatives include mmHg, atm, or bar.

Q5: How is this different from Dalton's law of partial pressures?
A: This formula is essentially an application of Dalton's law, which states that the total pressure of a gas mixture equals the sum of the partial pressures of its individual components.