Apply Dalton’s law: one gas’s pressure from its mole fraction and the total pressure.
| p_i | – |
Use this calculator for a gas-mixture problem or a dry-air correction when you know x and P_tot.
The calculation is pᵢ = xᵢ × P_tot. Mole fraction is 0–1, not a percent. The same pressure unit comes out as you put in.
This is Dalton’s law for an ideal mixture. It does not apply a fugacity coefficient or a water-vapour correction unless that is already folded into x or P_tot.
Mole fraction x: Mole fraction of the gas, 0 to 1. Dry air oxygen is about 0.21.
Total P: Total pressure in any unit you want back, kPa, bar, or atm.
p_i: Partial pressure of that gas in the same unit as total P.
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