CONTACTING OF GASES AND SOILDS

Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases. The following figure illustrates the microscopic differences.

Microscopic view of a gas.	Microscopic view of a liquid.	Microscopic view of a solid.

Note that:

• Particles in a:
• gas are well separated with no regular arrangement.
• liquid are close together with no regular arrangement.
• solid are tightly packed, usually in a regular pattern.
• Particles in a:
• gas vibrate and move freely at high speeds.
• liquid vibrate, move about, and slide past each other.
• solid vibrate (jiggle) but generally do not move from place to place.

Liquids and solids are often referred to as condensed phases because the particles are very close together.
The following table summarizes properties of gases, liquids, and solids and identifies the microscopic behavior responsible for each property.

Some Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for the Behavior
gas	liquid	solid
assumes the shape and volume of its container particles can move past one another	assumes the shape of the part of the container which it occupies particles can move/slide past one another	retains a fixed volume and shape rigid - particles locked into place
compressible lots of free space between particles	not easily compressible little free space between particles	not easily compressible little free space between particles
flows easily particles can move past one another	flows easily particles can move/slide past one another	does not flow easily rigid - particles cannot move/slide past one another

Solids, liquids and gases - Read

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Introduction

Solids, liquids and gases have different properties.

Liquids and gases can flow. Solids keep their shape. Gases can be squashed.

This section includes:

• Solids
• Liquids
• Gases

• Pag

Solids

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• Solids stay in one place and can be held.
• Solids keep their shape. They do not flow like liquids.
• Solids always take up the same amount of space. They do not spread out like gases.
• Solids can be cut or shaped.
• Even though they can be poured, sugar, salt and flour are all solids. Eachparticle of salt, for example, keeps the same shape and volume.
• Heating some solids can turn them into liquids.
  
• Cooling a liquid can turn it into a solid.
  

  Examples of Gas to Solid

  

  There are three states of matter: solids, liquids and gases. In many cases, the same element can exist in all three states.

  Phase Transitions

  When matter changes from one state to another it is called a phase transition. Examples include:

  • Gas to solid phase transitions are known as "deposition."

  • Gas to liquid phase transitions are known as "condensation."

  • Liquid to gas phase transitions are known as "vaporization."
  • Liquid to solid phase transitions are known as "freezing."
  • Solid to liquid phase transitions are known as "melting."
  • Solid to gas phase transitions are known as "sublimation." In most cases, solids turn into gases only after an intermediate liquid state.

  There are many examples of matter going through each of these transitions. 

  Examples of Gas to Solid (Deposition)  

  Under certain circumstances, gas can transform directly into a solid. This process is called deposition.  

  • Water vapor to ice - Water vapor transforms directly into ice without becoming a liquid, a process that often occurs on windows during the winter months.
  • Physical vapor to film - Thin layers of material known as "film" are deposited onto a surface using a vaporized form of the film.

  Examples of Gas to Liquid (Condensation)  

  • Water vapor to dew - Water vapor turns from a gas into a liquid, such as dew on the morning grass.  
  • Water vapor to liquid water - Water vapor fogs up glasses when moving into a warm room after being in the cold
  • Water vapor to liquid water - Water vapor forms water droplets on the glass of a cold beverage.

  Examples of Liquid to Gas (Vaporization)  

  • Water to steam - Water is vaporized when it is boiled on the stove to cook some pasta, and much of it forms into a thick steam.  
  • Water evaporates - Water evaporates from a puddle or a pool during a hot summer’s day.

  Examples of Liquid to Solid Phase Transition (Freezing)  

  • Water to ice - Water becomes cold enough that it turns into ice.  In fact, every known liquid (except for helium) is known to freeze in low enough temperatures.  
  • Liquid to crystals - Most liquids freeze by a process that is known as "crystallization," whereby the liquid forms into what is known in the scientific world as a "crystalline solid."

  Examples of Solid to Liquid (Melting)  

  • Solid to liquid - Melting occurs when something that is solid turns back into a liquid; it is the opposite of freezing.  
  • Ice to water - Ice melts back into water when it is left out at temperatures above the freezing point of 32 degrees.  
  • Rocks to lava - Rocks in volcanoes can be heated until they are molten lava.
  • Metal to molten liquid - Metals such as steel and bronze can be molten down. They can also be reformed as solids.

  Examples of Solid to Gas (Sublimation)  

  • Dry Ice - Solid carbon dioxide is known as "dry ice" and sublimates at room temperature.
  • Freeze-drying - Water can be sublimated in a food product by using a vacuum.

  Now you have some examples of gas to solid and can better understand how transitions occur between different states of matter.