States of Matter
We look at five states of matter on the site. Solids, liquids, gases, plasmas, and Bose-Einstein condensates (BEC) are different states that have different physical properties. Each of these states is also known as a phase. Elements and compounds can move from one phase to another when specific physical conditions change. For example, when the temperature of a system goes up, the matter in the system becomes more excited and active. If enough energy is placed in a system, a phase change may occur as the matter moves to a more active state.
Think about it this way. Let’s say you have a glass of water (H2O). When the temperature of the water goes up, the molecules get more excited and bounce around a lot more. If you give a liquid water molecule enough energy, it escapes the liquid phase and becomes a gas.
Have you ever noticed that you can smell a turkey dinner after it starts to heat up? As the energy of the molecules inside the turkey heat up, they escape as a gas. You are able to smell those volatile molecules that are mixed in the air.
It’s About the Physical"Phase" describes a physical state of matter. The key word to notice is physical. Things only move from one phase to another by physical means. If energy is added (like increasing the temperature) or if energy is taken away (like freezing something), you have created a physical change.
When molecules move from one phase to another they are still the same substance. There is water vapor above a pot of boiling water. That vapor (or gas) can condense and become a drop of water in the cooler air. If you put that liquid drop in the freezer, it would become a solid piece of ice. No matter what physical state it was in, it was always water. It always had the same chemical properties.
On the other hand, a chemical change would build or break the chemical bonds in the water molecules. If you added a carbon (C) atom, you would have formaldehyde (H2CO). If you added an oxygen (O) atom, you would create hydrogen peroxide (H2O2). Neither new compound is anything like the original water molecule. Generally, changes in the physical state do not lead to any chemical change in molecules.
Or search the sites for a specific topic.
- Phase Change I
- Phase Change II
- BE Condensate
- Mixtures I
- Mixtures II
- Solutions I
- Solutions II
- Mixture Ex.
- More Topics
Liquid Lakes on Titan (NASA/JPL Video)
Source: Angewandte Chemie/Wiley
Useful Reference MaterialsEncyclopedia.com:
NYU.edu (What is matter?):
Books on Amazon.com:
- Prentice Hall Chemistry (Wilbraham)
- Chemistry (McMurry)
- Chemistry: The Molecular Nature of Matter and Change (Silberberg)
- Books on States of Matter