Partial Pressure Calculator

- May 10, 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.

Understanding Partial Pressure

Partial pressure refers to the pressure that a single gas in a mixture would exert if it alone occupied the entire volume. It plays a vital role in various scientific fields, including Chemistry and environmental Science. This concept helps us understand how different gases behave when mixed together in a container. Each gas in a mixture contributes to the total pressure, and knowing how to calculate these values is essential.

Why Use the Partial Pressure Calculator?

The Partial Pressure Calculator simplifies the process of finding the partial pressure of gases in mixtures. Using this tool can save you time and effort. It’s particularly helpful in situations like:

  • Studying gas mixtures in laboratory settings.
  • Understanding atmospheric conditions.
  • Calculating gas pressures in industrial processes.

Two Ways to Calculate

This calculator offers two different methods for calculation: the Mole Fraction Method and the Gas Mixture Method. The Mole Fraction Method calculates partial pressure using the mole fraction of a gas relative to the total pressure. The Gas Mixture Method allows you to input multiple gas components for a more detailed calculation. Both methods are intuitive and user-friendly.

Mole Fraction Method Explained

In the Mole Fraction Method, you need to provide two key pieces of information: the total pressure and the mole fraction of the gas you're analysing. The calculation follows Dalton’s Law, which states that the total pressure is equal to the sum of the partial pressures. This method is straightforward and ideal for situations where you know the mole fraction.

Gas Mixture Method Breakdown

The Gas Mixture Method is designed for more complex scenarios involving multiple gases. You simply enter the total pressure and the number of moles for each gas component. This method is great for analysing mixtures like air or natural gas, providing a comprehensive breakdown of how each gas contributes to the total pressure.

Units of Measurement

When using the calculator, you can choose from various units of pressure, including:

  • Atmospheres (atm)
  • Kilopascals (kPa)
  • Millimetres of Mercury (mmHg)
  • Bars
  • Torr
  • Pounds per square inch (psi)

This flexibility allows you to work in the unit that best fits your needs or preferences.

Getting Results

Once you input your values, the calculator will show you results such as the partial pressure of individual gases and the total pressure of the mixture. It also provides additional information, like the mole fractions and a breakdown of gas contributions. This makes it easier to understand the dynamics of gas mixtures.

Learn More About Dalton’s Law

Dalton’s Law of Partial Pressures is the theoretical foundation behind this calculator. The law states that each gas in a mixture behaves independently of others, exerting its pressure as if it were alone. Understanding this principle can enhance your grasp of gas behaviour in various applications, from chemical reactions to environmental studies.