Chp. 15 pp. 363-379
Atom- the smallest component of an element having the chemical properties of the element
Molecule- 2 or more atoms held tightly together
I.
II.
III.
Phases of Matter
a. Easiest way to describe matter
b. Solid- definite volume and shape
c. Liquid- definite volume and indefinite shape
d. Gas - indefinite volume and indefinite shape
e. Submicroscopic level (can’t see)
i. Solid-bonds between molecules are strong enough to hold them in a fixed position.
ii. Liquid- molecules slip past one another like marbles in a bag
iii. Gas- molecules bounce off one another
Physical and Chemical Properties
a. Physical properties- describe the physical attributes of a substance
i. color
ii. hardness
iii. density
iv. texture
v. phase
vi. Surface Tension – caused by the attraction between water molecules (Hydrogen Bonds)
vii. Specific Heat Capacity- 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.
b. Physical change
i. Physical change- change in some physical property of a substance
1. Ex. Melting Ice, boiling water, freezing water
a. All substances are still water
(MAINTAINS IT’S CHEM. ID)
b. Phase Changesi. Evaporation- Liquid to gas
ii. Sublimation- solid to gas
iii. Condensation- gas to liquid
iv. Melting- solid to liquid
v. Freezing- liquid to solid
c. Chemical properties- the tendency of a substance to transform into another substance
i. Chemical change- atoms rearrange and switch partners
1. Ex. Iron
Rust
Iron atoms break apart and combine with oxygen atoms
2. Ex: Grape juice
Wine
Sugar molecules rearrange to make alcohol molecules.
b. Substances change (DO NOT MAINTAIN CHEM. ID)
3. Chemical change means there is a new chemical
4. Physical change means there are just new attributes to the same chemical
5. Hard b/c there is a change in appearance for both phys. and chem. changes.
Elements, Compounds and Mixtures
a. Element- only one type of atom
i. EX: H, O, C, B, He, O2, H2,
b. Compound- atoms of different elements attached to one another
i. EX: Sodium (Na) atoms and Chlorine (Cl) atoms
Sodium chloride (NaCl) = Table Salt
c. Chemical Formula- represents a compound
i. EX: NaCl, H2O, MnO2
d. Mixtures- elements and compounds,
compounds and compounds or
mixture of elements
i. EX: Sea Water = mixture of H2O and a variety of salts
Air = Mixture of N2, O2, and other gases
ii. Can separate mixtures by knowing the physical properties of the mixtures components.
1. Boiling pts.
2. Melting pts.
3. Color…