Chemistry

Physical Chemistry

There are 3 states of matter:  solid, liquid, gas
Changes of state:

Something that is solid at room temperature but turns to liquid when heated is molten. (i.e. candle wax)
Solidification is the change of state from liquid to solid of a substance which is a solid at room temp. and atmospheric pressure.
Melting is the change of state from solid to liquid (usually caused by heating).
Freezing is the change of state from liquid to solid caused by cooling a liquid. 
Fusion is the change of state from solid to liquid of a substance which is solid at room temp and pressure.  (similar to molten)
Evaporation is a change of state from liquid to gas due to the escape of molecules from the surface.
Liquefication is a change of state from gas to liquid of a substance which is a gas at room temp and pressure.  (i.e. liquid hydrogen)
Condensation is a change of state from gas to liquid of a substance which is a liquid at room temp and pressure
Sublimation is the change of state from solid to gas on heating, and from gas to solid on cooling - a liquid is never formed. 


Elements, Compounds, and Mixtures - Oh MY!
An element is a substance which cannot be split into a simpler substance by a chemical reaction.  (i.e. Hydrogen, Helium, etc...)
A compound is a combination of 2 or more elements bonded together in some way.  It has different physical and chemical properties from the elements it is made of.  (i.e. Water = H2O....Hydrogen and Oxygen are combined to form a compound).

A mixture is a blend of 2 or more elements and/or compounds which are not chemically combined.  The proportions of each element or compound are not fixed and each keeps its own properties.  A mixture can usually be separated into its elements or compounds easily by physical means.

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