Vaporization

Examples of Vaporization in the following topics:

• Humidity, Evaporation, and Boiling

  • The amount of water vapor the air can hold depends on its temperature.
  • The capacity of air to hold water vapor is based on vapor pressure of water.
  • The vapor pressure of water at 100ºC is 1.01×105 Pa, or 1.00 atm.
  • (b) As the temperature rises, water vapor enters the bubble because its vapor pressure increases.
  • (c) At 100ºC, water vapor enters the bubble continuously because water's vapor pressure exceeds its partial pressure in the bubble, which must be less than 1.00 atm.

• Evaporation

  • Evaporation is a type of vaporization of a liquid that only occurs on the liquid's surface.
  • With sufficient heat, however, the liquid would quickly turn into vapor.
  • Evaporation of water occurs when the surface of the liquid is exposed, allowing molecules to escape and form water vapor; this vapor can then rise and form clouds.
  • This vapor density and the partial pressure it creates are the saturation values.
  • They depend only on the vapor pressure of water.

• Latent Heat

  • Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces.
  • Even more energy is required to vaporize water; it would take 2256 kJ to change 1 kg of liquid water at the normal boiling point (100ºC at atmospheric pressure) to steam (water vapor).
  • A phase change we have neglected to mention thus far is sublimation, the transition of solid directly into vapor.
  • The opposite case, where vapor transitions directly into a solid, is called deposition.
  • The system is constructed so that no vapor evaporates while ice warms to become liquid water, and so that, when vaporization occurs, the vapor remains in of the system.

• The Evaporating Atmosphere

  • Likewise, every once in a while a vapor molecule collides with the liquid surface and condenses into the liquid.
  • The water vapor in it changes phases.
  • Collisions between water molecules in the atmosphere allows some to condense and some to remain in vapor.

• Convection

  • If the water vapor condenses in liquid droplets as clouds form, heat is released in the atmosphere (this heat release is latent heat)  .
  • Water vapor carried in by convection condenses, releasing tremendous amounts of energy, and this energy allows air to become more buoyant (warmer than its surroundings) and rise.
  • Cumulus clouds are caused by water vapor that rises because of convection.

• Mass Spectrometer

  • First, the sample undergoes vaporization by intense heat.

• Phase Changes and Energy Conservation

  • These amounts of energy are the molar heat of vaporization and molar heat of fusion.

• Speed of Sound

  • The vapor cone is made just before it reaches the speed of sound and is caused by a sudden drop in air pressure.

• Momentum Transfer and Radiation Pressure Atom

  • As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus.

• Greenhouse Gases and Global Warming

  • The gases in the atmosphere, primarily CO2 and water vapor are highly absorbent in the infrared part of the spectrum.