States of Matter

Solids Neither take the shape or volume of container Atoms are very close together –Not very compressible Atoms vibrate in place but don’t “get anywhere”

Liquids Take the shape but not the volume of container Atoms are very close together –Not very compressible Molecules can “get around” –This produces diffusion

Gases Take shape and volume of container Molecules are far apart –So gases are compressible –Molecules moving about 1000 mph Molecules can “get around” quickly –So gases also show diffusion Gas pressure is molecules colliding with walls of container

Liquid Crystals Intermediate phase –Between liquid and solid It is a liquid, but has crystalline properties Used extensively in LCD’s

Molecules Group of 2 or more atoms bound together Diatomic, triatomic, etc → billions of atoms Homoatomic – O 2, H 2, N 2 Heteroatomic – H 2 O, NH 3, CO 2, CO Limit of physical subdivision Smallest unit of a compound 10 million known /week Natural vs synthetic Diatomic or polyatomic

Chemical Formulas Specify composition of substance Symbols with subscripts For ionic compounds (non-molecular or extended network) – gives ratio If parentheses, treat like math Assumed - 1

Metals Some can be quite toxic –Mercury –Nickel Some thought to be toxic have been found to be essential to life in small quantities –Chromium

Alloys Mostly solid solutions – homogeneous mixtures Two main kinds –Interstitial alloys – steel –Substitutional alloys – brass and bronze

Alloys Mostly solid solutions – homogeneous mixtures Two main kinds –Interstitial alloys – steel –Substitutional alloys – brass and bronze Non-homogeneous –Small crystals –Like solder

Websites of Interest Do some exploring

H3 – C , 18, 20, 23, 24, 28, 34, 44, 47, 48, 55