What Is an Isochoric Process?
An isochoric process, also known as an isometric or isovolumetric process, is a thermodynamic process in which the volume of the system remains constant. During this process, other properties like temperature and pressure may change, but the system does not expand or compress.
Section 2: Key Principles of an Isochoric Process
The defining principle of an isochoric process is that the change in volume (ΔV) is zero. Consequently, no pressure-volume work is done by or on the system. According to Gay-Lussac's Law, for a fixed mass of gas at constant volume, the pressure is directly proportional to the absolute temperature. This means if you increase the temperature, the pressure will also increase.
Section 3: A Practical Example
A common example of an isochoric process is heating a gas in a sealed, rigid container. Imagine a pressure cooker with the lid tightly sealed. As you heat the cooker, the volume of the steam and air inside cannot change. The added heat increases the temperature of the gas, causing the pressure inside the cooker to rise significantly.
Section 4: Importance and Applications
Isochoric processes are crucial for understanding the First Law of Thermodynamics. Since no work is done, the change in the system's internal energy is equal to the amount of heat transferred. This concept is fundamental to the operation of certain cycles in internal combustion engines, such as the Otto cycle, and is used in calibrating bomb calorimeters to measure the heat of combustion.