Phases of Matter - Chp. 15 pp. 363-379

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Phases of Matter - Chp. 15 pp. 363-379

• Easiest way to describe matter
• Solid- definite volume and shape
• Liquid-definite volume and indefinite shape
• Gas-indefinite volume and indefinite shape

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Submicroscopic level - (cant see even with a
microscope)

• Solid-attractions between atoms and molecules are
  strong
• enough to hold them in a fixed position.

Water- (snowflake)
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Submicroscopic level - (cant see)

• Liquid- molecules slip past one another like
  marbles in a bag

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Submicroscopic level
(CANT SEE)

• Gas- molecules bounce off one another

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Physical and Chemical Properties

• Physical properties-describe the physical
  attributes of a substance
• color
• Hardness
• Specific Heat Capacity- the heat required to
  change the temp. of a unit mass of a substance by
  1? (how fast things heat up)
• EX. Gold- yellowish, soft, dense at
• room temperature.

• density
• texture
• phase (solid, liquid or gas)

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Surface Tension

• Caused by the attraction between molecules.

Which one?
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Physical change-

• Physical change- change in some physical property
  of a substance
• Ex. Melting Ice, boiling water, freezing water
• All substances are still water (It maintains its
  chemical identity)

Solid Phase
Gas Phase
Liquid Phase
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Phase Changes-

• Evaporation-
• Liquid to gas
• Sublimation-
• solid to gas
• Condensation-
• gas to liquid
• Melting-
• solid to liquid
• Freezing-
• liquid to solid

(Vaporizing)
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Endothermic-absorb heat
Exothermic- release heat

• Melting
• Boiling
• Sublimation

• Freezing
• Condensation

(Vaporizing)
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Endothermic-absorb heat
Exothermic- give off heat
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Chemical properties- the tendency of a substance
to transform into another substance

• Chemical change- atoms rearrange and switch
  partners
• Iron atoms break apart and combine with oxygen
  atoms
• Ex. Iron Rust
• Ex Grape juice Wine
• Sugar molecules rearrange to make alcohol
  molecules.

Fe
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Chemical change

• Chemical change means there is a new chemical
• Physical change means there are just new
  attributes
• Hard to tell the difference because there is a
  change in appearance for both changes in many
  cases.

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Elements, Compounds and Mixtures
H2
H2O
H2O NaCl
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Element- consisting of only one
type of atom

• 118 elemental materials
• 90 naturally occurring elements
• EX H, O, C, B, He, O2, H2,

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Compound- atoms of different elements attached to
one another

• EX Sodium (Na) atoms Chlorine (Cl) atoms
• Sodium chloride (NaCl)
• Table Salt

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Chemical Formula- represents a compound

• EX
• NaCl Sodium Chloride salt
• H2O dihydrogen monoxide
• H2O2 ?
• MnO2 ?

dihydrogen dioxide
Manganese dioxide
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Mixtures- elements and compounds, compounds and
compounds or mixture of elements

• Sea Water mixture of H2O and a variety of salts
• Air Mixture of N2, O2, and other gases
• Can separate mixtures by knowing the physical
  properties of the mixtures components.
• Boiling pts.
• Melting pts.
• Color