Dalton's Law Calculator Formula
Understand the math behind the dalton's law calculator. Each variable explained with a worked example.
Formulas Used
Total Pressure
p_total = p_a + p_b + p_cMole Fraction of Gas A
mole_frac_a = p_a / (p_a + p_b + p_c)Variables
| Variable | Description | Default |
|---|---|---|
p_a | Partial Pressure of Gas A(atm) | 0.5 |
p_b | Partial Pressure of Gas B(atm) | 0.3 |
p_c | Partial Pressure of Gas C (0 if none)(atm) | 0.2 |
How It Works
Dalton's Law of Partial Pressures
Formula
P_total = P_A + P_B + P_C + ...
Each gas in a mixture exerts pressure independently as if it alone occupied the container. The partial pressure of each gas equals its mole fraction times the total pressure:
P_i = x_i × P_total
Worked Example
A mixture of N₂ (0.5 atm), O₂ (0.3 atm), and CO₂ (0.2 atm).
- 01P_total = P_A + P_B + P_C
- 02P_total = 0.5 + 0.3 + 0.2
- 03P_total = 1.0 atm
- 04Mole fraction of A = 0.5 / 1.0 = 0.50
Frequently Asked Questions
What is Dalton's Law?
It states that the total pressure of a gas mixture equals the sum of the partial pressures of each individual gas. Each gas behaves independently.
What is a partial pressure?
The partial pressure of a gas in a mixture is the pressure it would exert if it occupied the entire volume alone at the same temperature.
When does this law fail?
Dalton's Law works best for ideal gases. It becomes inaccurate at very high pressures or when gases react with each other.
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