Partial pressure

Definition

Partial pressure is the pressure exerted by a single type of gas in a mixture of gases. It is proportional to its mole fraction and the total pressure of the mixture.

5 Must Know Facts For Your Next Test

1. According to Dalton's Law of Partial Pressures, the total pressure of a gas mixture is equal to the sum of the partial pressures of each individual component.
2. Partial pressure can be calculated using $P_i = x_i \cdot P_{total}$, where $P_i$ is the partial pressure, $x_i$ is the mole fraction, and $P_{total}$ is the total pressure.
3. In phase changes, understanding partial pressures helps explain phenomena like evaporation and boiling point changes.
4. The concept of partial pressure is crucial in explaining gas exchange processes in biological systems such as respiration.
5. Henry's Law states that the amount of gas dissolved in a liquid is directly proportional to its partial pressure above the liquid.

Review Questions

• What law explains how to calculate the total pressure from individual partial pressures?
• How do you determine the partial pressure of a gas in a mixture if you know its mole fraction and total pressure?
• Why is understanding partial pressures important in explaining phase changes?

Related terms

Dalton's Law: A law stating that in a mixture of non-reacting gases, the total pressure exerted equals the sum of the partial pressures of individual gases.

Mole Fraction: A dimensionless quantity representing the ratio of moles of one component to the total moles in a mixture.

Henry's Law: A law stating that at constant temperature, the solubility of a gas in a liquid is directly proportional to its partial pressure above that liquid.