Problem 95 - Chemistry: An Atoms-Focused Approach

Question

What is meant by the partial pressure of a gas?

Step-by-Step Solution

Answer

Define partial pressure and explain its importance in a mixture of gases, particularly in biological systems like gas exchange during respiration.

Step 1: Define Partial Pressure

Partial pressure of a gas is the pressure that a gas in a mixture would exert if it alone occupied the same volume at the same temperature. In other words, it is the pressure that each gas contributes to the total pressure of the mixture.

Step 2: Dalton's Law of Partial Pressures

To better understand the concept of partial pressure, we need to discuss Dalton's Law of Partial Pressures. This law states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of each individual gas in the mixture. Mathematically, it can be represented as follows: \[P_{total} = P_1 + P_2 + P_3 + ... + P_n\] Where \(P_{total}\) is the total pressure of the mixture and \(P_1, P_2, P_3, ...\), are the partial pressures of each individual gas in the mixture.

Step 3: Importance of Partial Pressure in Gas Exchange

Partial pressure of gases plays a key role in biological systems' gas exchange processes, such as respiration. In the human respiratory system, the partial pressure is the driving force for the movement of oxygen and carbon dioxide between the lungs and blood cells. A higher partial pressure of oxygen in the lungs compared to the blood drives oxygen to move into the blood. Conversely, a higher partial pressure of carbon dioxide in the blood drives it to move into the lungs, where it can be exhaled. In summary, the partial pressure of a gas is the pressure it contributes to the total pressure of a mixture of gases. It is important for various applications, including gas exchange processes in biological systems.