What is the difference between partial pressure and vapor pressure? In short, partial pressure is the pressure of a gas in a mixture, while vapor pressure is the pressure of a liquid in equilibrium with its vapor. To understand these concepts better, let’s take a closer look at each one.
What is Partial Pressure?
Partial pressure is a term used in chemistry to describe the pressure that each gas in a mixture exerts on the container walls. The total pressure of a gas mixture is the sum of the partial pressures of the individual gases.
- Partial pressure is usually abbreviated as “P” followed by the name of the gas, so carbon dioxide would be written as “PCO2.” The partial pressure of a gas is directly proportional to its mole fraction in the mixture.
- For example, if a container holds a mixture of gases and one of those gases has a mole fraction of 0.4, then that gas will have a partial pressure that is 0.4 times the total pressure of the mixture.
- Partial pressures are also affected by temperature, with higher temperatures leading to higher partial pressures. Partial pressure is an important concept in fields such as atmospheric science and environmental engineering.
What is Vapor Pressure?
Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. Vapor pressure is an indication of a liquid’s evaporation rate. The higher the vapor pressure of a liquid, the faster it will evaporate.
- Vapor pressure is affected by temperature, and as temperature increases, so does vapor pressure. The boiling point of a liquid is the temperature at which its vapor pressure equals the atmospheric pressure.
- When the Vapor Pressure of a liquid is equal to the atmospheric pressure, the liquid will boil. Vapor Pressure can be used to predict how much of a volatile product will be lost to evaporation over time.
- Vapor Pressure can also be used to help design safe containers for volatile products. By understanding Vapor Pressure, we can better control how products are stored and transported.
Difference between Partial Pressure and Vapor Pressure
Partial Pressure and Vapor Pressure are two terms that are often used interchangeably, but there is a distinction between the two.
- Partial Pressure is the pressure that each gas in a mixture exerts on the container walls and is equal to the sum of the partial pressures of the individual gases.
- Vapor Pressure is the pressure of a gas above a liquid surface and is a result of the evaporation of the liquid.
- In order for vaporization to take place, the molecules must overcome intermolecular forces and enter the gas phase.
- The vapor pressure of a liquid is dependent on temperature, with higher temperatures resulting in higher vapor pressure.
Partial Pressure and Vapor Pressure are related, but Partial Pressure specifically refers to mixtures of gases, while Vapor Pressure refers to the pressure exerted by a gas above a liquid surface.
In order to understand the difference between partial pressure and vapor pressure, it’s important to first understand what each term means. Partial pressure is the measure of gas pressure exerted by a particular component of a mixture of gases in contact with a liquid or solid. Vapor pressure, on the other hand, is the measure of equilibrium vapor density above a flat surface containing pure liquid at a given temperature. Now that we have a basic understanding of these two terms, let’s take a closer look at how they differ.
Vapor pressure is always greater than partial pressure because the vapor molecules are constantly escaping from the liquid into the air. This means that as more vapors escape, the vapor pressure will continue to rise until it reaches equilibrium. Partial pressure, on the other hand, depends on both the amount of gas present and its concentration within the mixture. Finally, remember that partial pressure applies only to ideal gases while vapor pressure applies to all types of liquids.