Mole Fraction and Partial Pressure Calculator

Analyze gas mixtures with instant fractions and outputs. Review formulas, examples, charts, and downloadable reports. Built for students, labs, classrooms, and accurate practice sessions.

Calculator Input

Enter total pressure, choose a unit, then add component names and moles. Empty rows are ignored.

Total Pressure

Pressure Unit

Decimal Precision

Component 1

Component 2

Component 3

Component 4

Component 5

Component 6

Formula Used

1. Total moles: \( n_{total} = n_1 + n_2 + n_3 + \dots + n_i \)

2. Mole fraction: \( x_i = \frac{n_i}{n_{total}} \)

3. Partial pressure: \( P_i = x_i \times P_{total} \)

4. Dalton's law: \( P_{total} = P_1 + P_2 + P_3 + \dots + P_i \)

The calculator first finds total moles. It then divides each component moles by total moles to get mole fraction. Finally, it multiplies each mole fraction by total pressure to get partial pressure.

How to Use This Calculator

  1. Enter the total pressure of the gas mixture.
  2. Choose the pressure unit you want to work with.
  3. Set the number of decimal places for reporting.
  4. Add gas names for each component row you plan to use.
  5. Enter positive mole values for every included gas.
  6. Click Calculate Mixture to generate the results.
  7. Review the result table, conversion cards, and Plotly graph.
  8. Use the CSV or PDF buttons to save your report.

Example Data Table

Sample mixture using total pressure of 2.50 atm.

Gas Moles Mole Fraction Partial Pressure (atm)
Nitrogen 1.20 0.4800 1.2000
Oxygen 0.80 0.3200 0.8000
Carbon Dioxide 0.50 0.2000 0.5000
Total 2.50 1.0000 2.5000

Frequently Asked Questions

1. What does mole fraction represent?

Mole fraction shows the share of one gas in a mixture. It equals the component moles divided by total mixture moles. All mole fractions together add to one.

2. What is partial pressure?

Partial pressure is the pressure contributed by one gas inside a mixture. Under Dalton's law, each gas behaves as if it alone occupied the container at the same temperature.

3. Can I use any pressure unit?

Yes. This calculator accepts atm, kPa, bar, mmHg, and psi. It converts total pressure internally, then returns partial pressures in your selected unit and also in atm.

4. Do I need every row filled?

No. Empty rows are ignored. Only rows with positive mole values are included in the calculation. This keeps the form flexible for small or larger mixtures.

5. Why do all mole fractions sum to one?

Because each mole fraction is a part of the same whole mixture. When every component amount is divided by the same total moles, the fractions add to one.

6. When is Dalton's law reliable?

Dalton's law works best for ideal gases and many low pressure mixtures. Real gases can deviate when pressure rises or intermolecular forces become more significant.

7. Can I export the results for reports?

Yes. Use the CSV button for spreadsheets or the PDF button for printable summaries. Both options use the result table generated after calculation.

8. What causes invalid results?

The most common issues are missing pressure, negative mole values, or leaving every mole input blank. Enter at least one positive component and a valid total pressure.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.