How do you calculate partial pressure using Dalton's Law of partial pressures?

To calculate partial pressure using Dalton's Law of partial pressures, add the pressures of each gas present.

Dalton's Law of partial pressures states that the total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in the mixture. This law assumes that the gases in the mixture do not interact with each other and behave independently.

To calculate the partial pressure of a gas in a mixture, first determine the mole fraction of that gas in the mixture. The mole fraction is the ratio of the number of moles of that gas to the total number of moles in the mixture. Then, multiply the mole fraction by the total pressure of the mixture to obtain the partial pressure of that gas.

For example, if a gas mixture contains 0.2 moles of oxygen and 0.8 moles of nitrogen, and the total pressure of the mixture is 1 atm, the mole fraction of oxygen is 0.2/(0.2+0.8) = 0.2. Therefore, the partial pressure of oxygen is 0.2 x 1 atm = 0.2 atm. Similarly, the partial pressure of nitrogen is 0.8 x 1 atm = 0.8 atm.

It is important to note that Dalton's Law of partial pressures only applies to ideal gases, which have no volume and no intermolecular forces. Real gases deviate from ideal behaviour at high pressures and low temperatures, and corrections must be made to account for this deviation.