Partial Pressure Calculator

Category: Chemistry
- March 18, 2025
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This calculator determines the partial pressure of a gas in a mixture using Dalton's Law of Partial Pressures.

According to Dalton's Law, the total pressure of a gas mixture equals the sum of the partial pressures of each individual gas.

Mole fraction is the ratio of moles of a component to the total moles in the mixture (0-1)
Optional: for STP/non-ideal gas calculations

About Dalton's Law of Partial Pressures

Dalton's law states that the total pressure exerted by a mixture of gases equals the sum of the partial pressures of individual gases in the mixture. Each gas in a container contributes to the total pressure as if it were the only gas present.

The partial pressure of a gas component (Pi) is calculated by:

Pi = Xi × Ptotal

Where Xi is the mole fraction of the gas and Ptotal is the total pressure of the gas mixture.

What is the Partial Pressure Calculator?

The Partial Pressure Calculator helps determine the pressure exerted by a single gas within a mixture. It follows Dalton's Law of Partial Pressures, which states that the total pressure of a gas mixture equals the sum of the partial pressures of each individual gas.

Formula for Partial Pressure

Dalton’s Law:

\[ P_{\text{i}} = X_{\text{i}} \times P_{\text{total}} \]

Where:

  • \(P_{\text{i}}\): Partial pressure of the gas
  • \(X_{\text{i}}\): Mole fraction of the gas
  • \(P_{\text{total}}\): Total pressure of the gas mixture

How to Use the Partial Pressure Calculator

The calculator provides two different methods for determining partial pressure:

1. Mole Fraction Method

  • Enter the total pressure of the gas mixture.
  • Input the mole fraction of the gas you want to analyze.
  • Select the preferred pressure unit (atm, kPa, mmHg, etc.).
  • Click the "Calculate Partial Pressure" button to get the result.

2. Gas Mixture Method

  • Enter the total pressure of the gas mixture.
  • Add individual gases by specifying their names and the number of moles present.
  • Select a predefined gas mixture for convenience (e.g., air, natural gas, synthesis gas).
  • Choose the preferred pressure unit.
  • Click "Calculate Partial Pressure" to view results, including a breakdown of each gas component.

Why Use This Calculator?

This tool is useful in various applications, including:

  • Chemistry and Physics: Understanding gas behaviors in controlled environments.
  • Engineering: Calculating pressure values for gas-related processes.
  • Medical Applications: Determining oxygen partial pressures in breathing systems.
  • Aviation and Diving: Ensuring safe air mixtures at different altitudes and depths.

FAQ

What is partial pressure?

Partial pressure refers to the contribution of a single gas to the total pressure in a mixture. It helps determine gas behavior and interactions in different environments.

How do I calculate mole fraction?

The mole fraction is calculated using:

\[ X_{\text{i}} = \frac{n_{\text{i}}}{n_{\text{total}}} \]

Where \(n_{\text{i}}\) is the moles of the gas and \(n_{\text{total}}\) is the total moles of all gases in the mixture.

Can I use different pressure units?

Yes, the calculator allows selection between various pressure units, including atm, kPa, mmHg, bar, torr, and psi.

What if I don’t know the mole fraction?

If you don’t know the mole fraction, use the Gas Mixture Method instead. Enter the number of moles for each gas, and the calculator will determine the partial pressures.

Final Thoughts

The Partial Pressure Calculator makes it easy to determine the pressure exerted by individual gases in a mixture. Whether you’re working on a chemistry project, analyzing gases for industrial use, or ensuring safe air mixtures, this tool provides quick and accurate results.