Dalton's Law Calculator

What is Dalton's Law of Partial Pressures?

Dalton's Law of Partial Pressures, formulated by John Dalton in 1801, states that the total pressure exerted by a mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases. This fundamental principle is crucial in understanding gas behavior in various fields, including chemistry, meteorology, and engineering.

Formula

The formula for Dalton's Law is:

\[ P_{total} = P_1 + P_2 + P_3 + ... + P_n \]

Where:

• \(P_{total}\) is the total pressure of the gas mixture
• \(P_1, P_2, P_3, ..., P_n\) are the partial pressures of individual gases

The partial pressure of each gas can be calculated using its mole fraction:

\[ P_i = x_i \times P_{total} \]

Where \(x_i\) is the mole fraction of gas i.

Calculation Steps

Let's calculate the partial pressures in a mixture of three gases:

• Total Pressure (\(P_{total}\)) = 5 atm
• Mole fraction of Gas 1 (\(x_1\)) = 0.2
• Mole fraction of Gas 2 (\(x_2\)) = 0.3
• Mole fraction of Gas 3 (\(x_3\)) = 0.5

1. Calculate partial pressure of Gas 1: \[ P_1 = x_1 \times P_{total} = 0.2 \times 5 \text{ atm} = 1 \text{ atm} \]
2. Calculate partial pressure of Gas 2: \[ P_2 = x_2 \times P_{total} = 0.3 \times 5 \text{ atm} = 1.5 \text{ atm} \]
3. Calculate partial pressure of Gas 3: \[ P_3 = x_3 \times P_{total} = 0.5 \times 5 \text{ atm} = 2.5 \text{ atm} \]
4. Verify Dalton's Law: \[ P_{total} = P_1 + P_2 + P_3 = 1 + 1.5 + 2.5 = 5 \text{ atm} \]

Example and Visual Representation

Let's visualize Dalton's Law for our gas mixture:

This visual representation shows:

• The total pressure of the gas mixture (5 atm)
• The partial pressures of each gas, represented by different colors
• How the partial pressures add up to the total pressure