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Matter, Solutions, & Solubility
I. Phases of Matter
A. The main differences in solids, liquids and gases is:
how close their particles are, the speed of the particles & type of motion
• B. kinetic molecular theory – particles of matter are in constant motion & the speed of the particles increases w/ increased temp
• 1. In solids, the particles are very close together, touching each other and packed tightly enough that the particles cannot move at all except to rotate on their axes & vibrate.
• a. SOLIDS - have definite shape and definite volume
• *usually HIGH density• *expands only slightly when heated• *almost incompressible because
particles are packed very close together.
• Crystalline - repeating geometric pattern–covalent network–metallic– ionic–covalent molecular
• Amorphous - no geometric pattern
decreasingm.p.
Types of Solids
Ionic(NaCl)
Metallic
• 2. In liquids, the particles touch each other constantly but can slide past each other as the liquid FLOWS.
• a. LIQUIDS – *have definite volume but not definite shape
• *usually SLIGHTLY less dense than solids
• *expand more than solids when heated• *almost incompressible; • *takes the shape of its container• *flows – viscosity refers to how quickly or
slowly a fluid flows or changes shape
B. Liquid Properties
• Surface Tension–attractive force between particles in a
liquid that minimizes surface area
Liquid Properties• Capillary Action–attractive force between the surface of a
liquid and the surface of a solid – paper towels!
water mercury
• 3. In gases, the particles are completely independent and do not touch each other continually.
• b. GASES - have no definite shape & no definite volume
• *very LOW density• *expand greatly when heated
• *highly compressible• *take the shape of the container • *flow• *particles are completely independent
and do not touch each other except when they bump into each other.
• 4. phase changes• a. melting/freezing – solid to liquid &
liquid to solid• b. boiling/condensating—liquid to gas
gas to liquid• c. sublimation/deposition—solid to
gas & gas to solid
Liquids vs. SolidsLIQUIDS
Stronger than in gases
Y
high
N
slower than in gases
SOLIDS
Very strong
N
high
N
extremely slow
IMF Strength
Fluid
Density
Compressible
Diffusion
Hydrogen Bonding
• Intermolecular forcesof attraction between
molecules
• Bonds exist withinmolecules
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 442
Water is an exception to the rule!Water becomes more dense as it gets colder UNTIL it reaches 4C – it is MOST dense at 4 C. As it gets colder (3 C & lower) it expands & so gets less dense. That is why ice floats in water!