States of matter defined

The discovery of supercritical fluids occurred in 1879, when Thomas Andrews actually described the supercritical state and used the term critical point. A supercritical fluid is a material above its critical point. It is not a gas, or a liquid, although it is sometimes referred to as a dense gas. It is a separate state of matter defined as all matter by both its temperature and pressure. Designation of common states in liquids, solids and gases, assume standard pressure and temperature conditions, or STP, which is atmospheric pressure and 0°C. Supercritical fluids generally exist at conditions above atmospheric pressure and at an elevated temperature. Figure 16.1 shows the typical phase diagram for carbon dioxide, the most commonly used supercritical fluid [1]. 

Gas A state of matter defined as a fluid with a vapor pressure exceeding 40 psia at 100° F. Gasolines Mixture of volatile, flammable liquid hydrocarbons used in internal combustion engines. Typical flash point temperature is around -40 °C. 

Gas A state of matter defined as a fluid widi a vapor pressure exceeding 40 psia at 100° F. 

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