Steam vs Vapor

on . Posted in Thermodynamics

matter phasesThe terms "vapor" and "steam" are often used interchangeably, but they can have slightly different meanings depending on the context. 

general explanation

  • Steam  -  Steam specifically refers to water vapor, which is the gaseous phase of water.  Steam is formed when liquid water is heated to its boiling point and undergoes vaporization, converting into a gas.  Steam is commonly associated with the use of water as a working fluid in various applications, such as power generation, heating systems, or industrial processes.  Steam is typically used in a controlled manner, and its properties, such as temperature and pressure, are often specified.
  • Vapor  -  In a broad sense, vapor refers to the gaseous phase of a substance that is typically a liquid or solid at room temperature and pressure.  Vapor can be formed through evaporation or sublimation, where the substance changes from a liquid or solid phase to a gas phase.  Examples of vapor include water vapor (gaseous water), gasoline vapor, or vaporized alcohol.  Vapor may not necessarily be saturated or at a specific temperature and pressure.

While all steam is vapor, not all vapor is steam.  Vapor is a more general term that refers to the gaseous phase of any substance, whereas steam specifically refers to the gaseous phase of water.  When discussing water in its gaseous phase, the term "steam" is commonly used.


Steam vs Vapor - Difference between Similar Terms

Terms Steam Vapor
Definition Steam is simply water vapor Vapor is the gageous state of any substance
Flammability Non-flammable Vapor of flammable substance is flammable
Temperature Steam exists above 100C at standard pressure Existance of vapor depends on the boiling point and volatility of the substance
Uses Generation of electricity, soil sterilization, heating buildings, etc. Perfumes, mist formation, production of mercury-vapor lamps to generate light, etc.
Visibility Typically invisible Some substance produce colorful vapor while others form colorless or invisible vapors


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Tags: Steam Vapor