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
Submicroscopic level -
(can’t see even with a microscope)
• Solid-attractions between atoms and
molecules are strong
• enough to hold them in a fixed position.
Water(snowflake)
Submicroscopic level - (can’t see)
• Liquidmolecules slip
past one
another like
marbles in a
bag
Submicroscopic level
(CAN’T SEE)
• Gas- molecules bounce off one another
Physical and Chemical Properties
• Physical properties-describe the physical
attributes of a substance
– color
– density
– Hardness
– texture
– phase (solid, liquid or gas)
– 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.
Surface Tension
• Caused by the attraction between
molecules.
Which one?
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 it’s
chemical identity)
Liquid Phase
Gas Phase
Solid Phase
• Evaporation- (Vaporizing)
Liquid to gas
• Sublimationsolid to gas
• Condensationgas to liquid
• Meltingsolid to liquid
• Freezingliquid to solid
Phase
Changes-
Endothermic-
Exothermic-
absorb heat
• Melting
release heat
• Freezing
• Boiling (Vaporizing)
• Sublimation
• Condensation
Endothermicabsorb heat
Exothermicgive off heat
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
Fe
– Ex: Grape juice
Rust
O
Fe
Fe
O
O
Wine
– Sugar molecules rearrange to make alcohol molecules.
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.
Elements,
H2
Compounds
H2 O
and Mixtures
H2O + NaCl
Element- consisting of only one
type of atom
• 118 elemental materials
• 90 naturally occurring elements
EX: H, O, C, B, He, O2, H2,
Compound- atoms of different
elements attached to one another
EX: Sodium (Na) atoms &
Chlorine (Cl) atoms
Sodium chloride (NaCl) =
Table Salt
Chemical Formula- represents a
compound
• EX:
• NaCl – Sodium Chloride – “salt”
• H2O – dihydrogen monoxide
• H2O2 – ? dihydrogen dioxide
• MnO2 – ? Manganese dioxide
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…