Partial Pressure Calculator
### Gas Thermodynamics & Dalton's Law of Partial Pressures **Dalton's Law** states that the total pressure exerted by a mixture of non-reacting ideal gases is equal to the sum of the partial.
⚙ Input Values
📊 Results
Embed on Your Website
Copy and paste this code into your website.
<iframe src="https://calcusolve.com/calculator/partial-pressure-calculator?embed=true" width="100%" height="600" frameborder="0" loading="lazy" title="Partial Pressure Calculator"></iframe> ⚖ Scenario Comparison
What This Means For You
Saved Calculations
No saved calculations yet.
Click "Save" to bookmark your current result.
📐 Formula
💡 Practical Example
Calculating the partial pressure of oxygen (20.95% mole fraction) in sea-level dry air at 1.000 atm total pressure: Yields 0.2095 atm, 21.23 kPa, and 159.22 mmHg.
📖 About Partial Pressure Calculator
Gas Thermodynamics & Dalton's Law of Partial Pressures
Dalton's Law states that the total pressure exerted by a mixture of non-reacting ideal gases is equal to the sum of the partial pressures exerted by each individual gas component.
Core Partial Pressure Equations
- Dalton's Law Sum: P_total = P_1 + P_2 + P_3 + + P_n = Σ P_i
- Mole Fraction Definition: x_i = (n_i) / (n_total)
- Individual Partial Pressure: P_i = x_i × P_total = ( (n_i) / (n_total) ) P_total
- Ideal Gas Law Form: P_i = (n_i R T) / (V)
Atmospheric Composition at Sea Level
- Nitrogen (N_2): 78.08\% P_N_2 = 0.7808 atm = 593.4 mmHg
- Oxygen (O_2): 20.95\% P_O_2 = 0.2095 atm = 159.2 mmHg
- Argon (Ar): 0.93\% P_Ar = 0.0093 atm = 7.1 mmHg
- Carbon Dioxide (CO_2): 0.04\% P_CO_2 = 0.0004 atm = 0.3 mmHg
How to Use This Calculator
Enter your Mole Fraction (xi or %) (e.g. 0.2095), Total Gas Mixture Pressure (e.g. 1.0 in atm), Component Gas Moles (ni) (e.g. 2.0 in moles), and Total Gas Mixture Moles (nTotal) (e.g. 10.0 in moles). Results update instantly as you type — adjust any value to compare scenarios.
The Formula
Dalton's Law: Pi = xi * Ptotal
Worked Example
Calculating the partial pressure of oxygen (20.95% mole fraction) in sea-level dry air at 1.000 atm total pressure: Yields 0.2095 atm, 21.23 kPa, and 159.22 mmHg.
Understanding Your Result
Evaluate your result in the context of your specific use case and relevant industry standards or reference values. A single calculated result is a starting point — test two to three scenarios to understand how sensitive the outcome is to your key input assumptions. For high-stakes decisions, verify your result against a secondary source or subject-matter expert before acting.
💡 Mathematical Rigor & Applied Context
- This calculator applies exact mathematical definitions following conventions established by NIST and international standards bodies.
- Rounding errors accumulate across multi-step calculations. For precision-critical work, maintain extra significant figures through all intermediate steps.
- Many mathematical concepts have multiple valid formulations — if a result seems unexpected, verify which convention or definition applies to your context.
- Dimensional analysis (unit tracking) is the fastest way to catch formula errors. Every term in an equation must have consistent, compatible units.
- Numerical methods used in digital calculators introduce floating-point precision limits (~15 significant digits for IEEE 754 double precision).
- For statistical and probabilistic calculations, always specify whether you are working with population parameters or sample statistics — formulas differ.
- Visualizing a problem geometrically or testing with known boundary values (zero, infinity, negative) reveals hidden errors faster than algebraic checking.
- When in doubt, validate your result against a simplified hand calculation or a published worked example from a textbook or standards document.
Results are for informational and educational purposes only. Always verify critical decisions with a qualified professional.