Dalton's Law of Partial Pressures Calculator
Add partial pressures to find the total pressure of a gas mixture, or use mole fractions with total pressure to find individual partial pressures.
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Combined Gas Law
Charles's Law
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Volume of Gas
What is Dalton's Law of Partial Pressures?
Dalton's Law states that in a mixture of non-reacting gases, the total pressure is equal to the sum of the partial pressures of each individual gas. Each gas behaves as if it were the only gas in the container.
The partial pressure of any gas can also be calculated using its mole fraction:
where Xᵢ is the mole fraction (moles of gas i / total moles).
Step-by-Step Example
Given: A container has 0.40 atm of N₂, 0.20 atm of O₂, and 0.10 atm of CO₂. Find P_total.
Applications
- Scuba diving: Understanding partial pressures of O₂ and N₂ is critical for avoiding oxygen toxicity and nitrogen narcosis at depth.
- Atmospheric science: Earth's atmosphere is a mixture of gases, each contributing its partial pressure to the total 1 atm.
- Medical gases: Anesthesiologists use Dalton's Law to calculate partial pressures of gas mixtures delivered to patients.
Frequently Asked Questions
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Dalton's Law of Partial Pressures states that the total pressure of a gas mixture equals the sum of the partial pressures of each individual gas: P_total = P₁ + P₂ + P₃ + ... Each gas exerts pressure independently as if it were alone in the container.
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Partial pressure is the pressure that one gas in a mixture would exert if it occupied the entire container alone at the same temperature. It can be calculated as Pᵢ = Xᵢ × P_total, where Xᵢ is the mole fraction of gas i.
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Mole fraction (Xᵢ) = moles of gas i / total moles of all gases. The sum of all mole fractions in a mixture always equals 1.