Final answer:
The symbol of a black circle with a cylinder inside indicates 'gases under pressure.' These gases, when compressed, have various uses in medical, industrial, and household settings. Understanding the properties and behaviors of compressed gases is crucial for their safe handling and application.
Step-by-step explanation:
The symbol described in the question, a black circle with a cylinder inside, represents gases under pressure. Compressed gases are substances in the gaseous state that have been pressurized in a cylinder or other container. These gases exhibit significant kinetic energy which allows them to fill the volume of their containers and can be compressed due to the large amount of space between particles. This high compressibility and the ability to expand makes them useful in various applications.
In the medical field, oxygen is often compressed and provided to patients with damaged lungs to assist with breathing. During surgeries, anesthetics may also come in the form of compressed gases. In industrial settings, gases like acetylene and oxygen are compressed for welding applications, creating very hot flames. Common household uses include compressed propane for barbeque grills. Understanding the behavior of compressed gases is essential for their safe and effective use.
Compressing gases can also lead to a change of state. For example, butane gas (C4H10) can be compressed to form a liquid inside a container, such as in a disposable lighter. The pressure increases the attraction between molecules resulting in the formation of a liquid from a gas. Hence, the behavior and application of compressed gases are subject to the principles of chemistry, particularly the study of gases and their physical properties.